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THE AGE AND GROWTH. 
OF SALMON AND TROUT 
IN NORWAY 


AS SHOWN BY THEIR SCALES 


. BY 


KNUT DAHL 
Translated from the Norwegian by lan Baillie 


EDITED BY 


J. ARTHUR HUTTON 


AND 


H. T. SHERINGHAM 


LONDON: Aenea 
THE SALMON AND TROUT ASSOCIATION, 
| FISHMONGERS’ HALL, E.C. 


«4 Ly aia: AABN LONG ERO ME ae 


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CONTENTS. 


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INTRODUCTION 


OBAP. 
I. Mezrnops or Ticvuietaiabna 


1. Salmon Scales 
(a) The Scales of Parr and Smolts before wien: 
(0) The Scales after Migration 


(c) The Scales after Salmon have demand to tig River. 
Formation of Spawning Mark . 


2. Trout Scales : 
The Spawning Mark : ‘ , ; s 
3. General Observations on the Use of Scales as a means towards the 
Determination of Growth 


II. On Satmon 


1. The Age and Characteristics of Parr and Smolts before Migration 
2. The Salmon after Migration : 

(a) The Ago of Smolts at the Period of Migration 

(>) The Age of Salmon after Migration 

(c) The Growth of Salmon after Migration . 


(d) The Relative Occurrence of the Different Yoar-Clasces in 
Different Localities 


(e) The Distribution of the Year- Classes 


III. On Trovr i : . ; : ‘ ‘ 
A. Instances of Sea-Trout and of the Rivers to which dens have Access . 


B. Instances of Trout from Waters to which Gea-Trowt have no 


Access 
1. Lake Mjgsen Trout 
2. Trout from other Lakes 


IV. GneRAL CoNncLusIONs AS TO THE PROBLEMS CONNECTED WITH THE 
GrowrH ofr SALMON anp TRovuT 


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INTRODUCTION. 


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Dorine the years 1898—1902, I carried out a series of investigations 
relating to the life-history of Salmon and Trout. The results were issued 
under the title of “ @rret og Unglaks” in 1902, and were afterwards 
published in English in the “‘ Nyt Magasin for Naturvidenskaberne ” 
B. 42, 1904, under the title of “‘ A Study on Trout and Young Salmon.” 

The main result of my numerous investigations and experiments was 
briefly this: that salmon of sizes between 16 cm. and 45 cm., or in other 
words salmon between the smolt stage and the grilse stage, were practically 
not to be found in those waters in which our salmon fisheries were carried 
on, that is to say in the rivers and fjords and among the outer islands along 
the coast. What had generally been supposed to be immature salmon were 
really sea-trout. This I was able to prove by rearing small salmon in salt 
water until they attained the requisite sizes, when they were found to be 
different from fish which had previously been considered immature salmon, and 
further confirmation of this was obtained by catching and examining quantities 
of sea-trout and showing that there were no small salmon among them. 
I finally sueceeded in ascertaining that immature salmon, in an earlier stage 
than grilse, are caught in the mackerel nets along our south coast far out at 
sea, and this discovery I have subsequently been able to confirm by further 
instances, of which I gave a brief description in 1906 ‘‘ Nyere oplysninger 
om Unglaks og dens Opholdssteder,” Norsk Fiskeritidende, 12te hefte, 
1906. 

As a result of these discoveries, when the new law with reference to 
salmon-fishing was passed in 1905, regulations were made exempting sea- 
trout fishing from certain restrictions, amongst others the obligation of a 
minimum mesh in non-stationary appliances (seines and gill nets). These 
restrictions had previously rendered such sea-trout fishing all but illegal 
everywhere, and had merely been imposed with the object of protecting the 
immature salmon that were supposed to constitute a portion of the catches 
made by this mode of fishing for sea-trout. 

During the discussion on this law it was even proposed to do away 
with all restrictions as to size of mesh in the case of salmon also. However, 
it was eventually decided to adhere to the minimum size of mesh previously 


vi _ INTRODUCTION. 


prescribed, viz.,5°8 cm. The principal argument put forward for retaining 
this minimum size of mesh, or, indeed, any prescribed size, was that it 
would result in the protection of small grilse, or at least such grilse as it 
was thought better to spare, with a view to their becoming of greater benefit 
to the fisheries on their subsequent return from the sea as larger fish. 

This argument carried with it so much weight that it became in my 
opinion a matter of the utmost importance to discover a suitable method of 
acquiring the fullest possible information on the questions of the salmon’s 
age, and rate of growth, and as to its life history generally. 

My previous investigations had also frequently brought me into contact 
with many problems relating to the marked tendency to variation shown by 
all the varieties and species of the Salmonidae, and especially to the 
remarkable disposition to variation possessed by all the numerous forms of 
trout. It has long been recognised that both salmon and trout may vary 
exceedingly in different localities, a difference which is often strikingly 
apparent in the size of the fish. For example, in the case of salmon it was 
well known, and it has also been proved by actual measurements, that along 
certain parts of the coast they were larger than at others, and, further, it was 
known that trout in certain lakes and streams attained considerable 
* dimensions; whereas in other waters, perhaps in the immediate vicinity, 
they barely succeeded in passing the limit at which they became sufliciently 
large for eating. 

This remarkable and long-recognised tendency to variation on the 
part of the fishes of the salmon species was accounted for, in various ways, 
by different investigators. 

As I have shown at length in my introduction to “ @Orret og Unglaks,” 
Linneus, when composing his “ Systema Nature” was evidently impressed 
by this tendency towards variation, and endeavoured to draw up a classifi- 
cation of the separate species of the salmon family, (salmon, sea-trout, 
burn-trout, mountain-trout, lake-trout, etc.) while later investigators, 
inspired by the same idea, have endeavoured to establish the existence of 
even agreater number of separate species. This practice was in fact carried 
so far, that actually the young of the ordinary salmon were described, and 
for a long time were known as an independent species (Salmo salmulus). 

However, the employment of a larger amount of material for the study 
of the species resulted in a perhaps rather exaggerated disposition to reduce 
their number, and the leading men of science at the end of last century, 
notably the two Swedes, Smitt and Liljeborg, reduced the whole family to 
merely two species, namely, salmon andtrout. Smitt even looked upon the 
trout as merely a variety of one main species, the Salmon (Salmo salar). All 
varieties of salmon and trout were thus held to be sub-species of one or more 
main species. 


INTRODUCTION. | vii 


Since that time opinions as to the causes in the variation in these 
species have chiefly followed two directions. According to one theory a 
number of local races exist, more or less widely distributed, and their 
peculiarities are based on the ordinary laws of selection and heredity. The 
other theory lays greater stress on the question of food supply. The : 
assertion has been put forward that peculiarities in shape and colour may 
easily be explained as being merely due to environment. The variation in 
size, which is undoubtedly the most striking and characteristic dissimilarity 
is explained as being due to different conditions of food supply. Others 
again are of opinion that these variations are due to both race and 
environment. 

For a fuller understanding of the subject it is absolutely necessary 
that one should be able to determine the age and rate of growth of the 
different fishes in their natural state in different localities, and it was for 
this reason that I considered it advisable to investigate the matter fully with 
a view to the classification of salmon and trout according to their age. 

The works published since 1899 by Hoffbauer, Reibisch, Heincke, and 
Stuart Thompson seemed to show that a classification of this kind was 
feasible in the case of carp, plaice, and several of the gadidae. In some 
cases by means of the scales and in others by investigating the bones it 
was demonstrated that there existed periodic forms of growth in summer 
and in winter, and that this difference was indicated by annual growth- 
rings in these parts, similar to the rings found in trees. 

Investigations into this question were inaugurated in 1904 under the 
supervision of Dr. Hjortat the Norwegian Fishery Institute, and Dr. Damas, 
and I devoted special attention to the age of the gadidae, first by studying 
their otoliths, and afterwards by examining their scales, which were found 
to lend themselves admirably to the purpose. Subsequently we extended 
these researches to many other species of fish, amongst others both sprats 
and herrings, and the results obtained have been most satisfactory. A 
summarised account of the history and literature of this work has been 
published by me in the “ Internationale Revue der Gesammten Hydrobio- 
logie and Hydrographie,” Bd. 11, 1909, under the title of ‘‘ The Assessment 
of Age and Growth in Fish.” 

The success attending our efforts led me in 1905 to extend my investi- 
gations to the scales of trout and salmon which showed a distinct annual ring 
formation. I was induced to proceed further with my investigations by 
the publication in the same year of the first published work on salmon 
scales, and which appeared as a contribution from Mr. H. W. Johnston in 
the “23rd Annual Report of the Fishery Board for Scotland.” 

From the University, to which I applied for support in carrying out 
systematic investigations, I received a grant during the years 1906 and 


viii INTRODUCTI ON. 


1907, which enabled me to obtain material sufficient to demonstrate that 
very important results might be obtained by collecting material on a larger 
scale, and more fully investigating the age and growth of the salmon stock 
in Norway. | 

In the autumn of 1907 I was requested by the Agricultural Department 
to submit a scheme for such investigations, and, in accordance with my 
proposals, the necessary funds have been annually placed at my disposal by 
the Storthing. 

In order to obtain material for investigation which would fully represent 
the salmon which are caught in our various fisheries in Norway, I selected 
three different parts of the coast, namely the Christiansand district, the 
Trondhjem district, and East Finmarken. Thanks to the courtesy of 
Herr Tobias Tobiassen of Christiansand and of Messrs. M. Thams & Co., 
Trondhjem, I have been able to collect examples of scales from the 
different ice-houses during the salmon-fishing season, either from the whole 
catch dealt with at the ice-houses, or from as many fish each day as it 
was possible to arrange for. These gentlemen have also very kindly 
allowed me access to their books, thus enabling me to obtain very 
valuable statistics throwing light on the representative value of the samples 
collected. I have further obtained from various other localities, partly 
through the kindness of private individuals and partly thanks to the 
assistance of fishery officials, samples of material throwing light on different 
side-issues, and I have also collected during my travels considerable 
numbers of samples of parr and smolts from the different rivers. 

With the progress of my studies on the salmon’s age it became 
increasingly evident that it was necessary and desirable to attempt at the 
same time a careful investigation into the age and growth of the trout and 
its many varieties. With this object in view I collected examples of trout 
and sea-trout scales from a number of localities ranging from Finmarken to the 
southernmost parts of Norway. Most of them I collected personally, though 
many private individuals interested in the subject gave me valuable assistance. 

From abroad and especially from Great Britain, I received much 
valuable help. Mr. Calderwood, the Fishery Inspector for Scotland, 
rendered me assistance on several occasions, and Dr. Holt was kind enough 
to send me over from Dublin a large saraple of Irish salmon scales. Mr. J. 
Arthur Hutton of Manchester also gave me invaluable assistance. His 
splendid micro-photographs of salmon scales are already known from his 
excellent papers on the subject, and he has now done me the favour of 
placing his technical experience at my disposal, and has kindly executed all 
the micro-photographs of scales from which the illustrations in this work 
are taken. I am also largely indebted to this gentleman for arranging and 
kindly supervising the English edition of the present paper. 


INTRODUCTION. | ix 


For comparison with our own fish I obtained from Denmark and 
Bavaria examples of trout, some captured in their wild state and others 
artificially reared. Some of these I collected myself in the course of 
a short journey during the autumn of 1909, and the rest were sent to me 
later. In this connection I have to thank Herr Smidt-Nissen of Ejstrup, ' 
Herr Pedersen of Vamdrup, the Bavarian Fishery Association, and 
Dr. Plehm of the Royal Bavarian Fishery Experimental Station in Munich, 
who was kind enough to collect samples for me. 

I likewise collected during my travels a few small samples of char and 
grayling for purposes of comparison. 

As regards the collection of material, I desire further to state that each 
fish was as a rule weighed and measured, and where possible the sexual 
organs were also examined. The data thus obtained were written down on 
an envelope in the case of every fish, and a sample of its scales was scraped 
off and placed inside the envelope in which they were dried. The sample 
of scales was taken whenever possible, from above the lateral line and a 
little behind a perpendicular line drawn from the posterior edge of the 
dorsal fin. 

The length of salmon was always measured by taking a line from the 
tip of the upper or lower jaw to the end of the median ray of the caudal fin. 
This method of measurement was adopted so as to accord with the previous 
measurements of salmon taken in Norway. 

In the case of trout and other fish it was found necessary for various 
reasons to measure the length from the tip of the snout (upper or lower 
jaw) to a perpendicular line drawn between the flukes of the caudal fin when 
spread out naturally, that is to say I employed the method adopted by 
Heincke for measuring herrings which has since come into general use in 
the International Ocean Researches for measuring all fish with forked 
tails. 

What follows has been arranged in such a manner that all important 
determinations of length and weight in relation to size and age are set down 
in tabular form in the Appendix. I shall begin by discussing the method 
employed and its possibilities, and then, by a comparison of the data con- 
tained in the tables, endeavour to elucidate the various problems connected 
with the age, growth, and general life-history of the different fish, in so far 
as these are affected by the knowledge obtained from the methods adopted. 


KNUT DAHL. 
BERGEN, 23rd May, 1910. 


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THE AGE AND GROWTH OF SALMON 
AND TROUT IN NORWAY. 


CHAPTER I. 
METHODS OF INVESTIGATION. 


1. Tue Soaues or Sanmon. 


Tue use of Salmon Scales as a means to the study of the age and other 
biological conditions of the fish is due, so far as I can ascertain, to Mr. 
H. W. Johnston. In three papers published in the Annual Reports of the 
Scottish Fishery Board for 1904, 1906, and 1907, he has succeeded in 
establishing the fact that periodic growth takes place in the scales of salmon, 
and that groups of rings are formed in each year, and that it is possible by 
counting the number of these to ascertain the age of nearly every individual, 
and to form an opinion regarding its life history. In the first article he 
relied mainly on scales taken from fish caught at various seasons of the 
year, and he succeeded in demonstrating by the study of these scales that 
various growth zones in the scales were formed in different periods of the 
year. In his later papers he was able to throw additional light on the 
subject from the investigation of scales of marked fish, and of ‘fish whose 
age was known. Mr. Johnston further made it clear that the scales of 
mature fish, which had returned to the river from the sea, were affected to 
a most remarkable extent by their sojourn in fresh water. When these fish 
returned to the sea after spawning and new growth was developed, the 
consequences of their stay in the river were shown by a permanent and 
ineffaceable scar on each scale, which Mr. Johnston termed the “ Spawning 
Mark.” His investigations have been supplemented and popularised by 
other English writers, notably Mr. Calderwood and Mr. Hutton.* 

In view of what had already been definitely proved, I decided to restrict 
my investigations towards ascertaining whether the same conditions applied 
also to Norwegian salmon, and also if possible to supply methods of 
investigation which might lend themselves to statistical analysis. 

* The latter author has also recently made a special study of salmon from the River 
Wye in England. 
AT. 1 


2 THE AGE AND GROWTH OF SALMON AND TROUT. 


The points on which I thought it important to obtain further information 
were the following :-— 

1. The growth of the scales of salmon-parr and smolts prior to 
migration. . 

2. The first growth of the scales in the sea. 

8. The formation of the annual rings in relation to the seasons of the 
year. 

4. The question whether all spawning fish were so affected by their 
stay in the river, that a “spawning mark ” would invariably be found on 
the scales of every salmon which had spawned. 

For the sake of those readers who may not have access to the publica- 
tions mentioned, I will endeavour, even at the risk of repeating what may 
have been previously published elsewhere, to describe the structure of the 
scales as found by me in my investigations on Norwegian salmon. 


(a.) Scales of Parr and Smolts prior to migration. 


If we examine the scale of a smolt or parr under the microscope we see 
at once that it consists of a transparent plate of an irregular elliptical 
shape, and that the under surface is smooth. The anterior portion, which 
is embedded in a pocket or fold of the skin, is characterised on the outer 
surface by a series of concentric elliptical rings, which are parallel with the 
outer edge of the scale. On the posterior or exposed portion of the scale, 
and which is the only portion that is visible before the removal of the 
adjacent and overlapping scales, these concentric lines or rings become, and 
especially with increasing age, most irregular and indistinct. 

A good illustration of the formation and growth of the scales during 
the first summer of the parr’s life was obtained from a number of specimens 
reared in 1898 in the State Hatchery at Haugsund, in Eker. I give below 
the results of the examination of six selected individuals, ten to twenty 
scales being examined in each case :— 


Number of Rings. 
Length in cm. Date Killed. Average. 
Minimum. Maximum. 

8 1/6 1 1 1* 
3°5 1/7 2 5 4° 
45 1/8 4 6 4°8 
55 1/9 4 8 6:2 
6 1/10 6 8 74 
10 1/11 12 19 16 


* The scale consisted of a very small plate, the edge of which may be regarded as 
identical with the first ring. 


METHODS OF INVESTIGATION. 8 


These parr were hatched in March, 1898, and killed during the course 
of the summer. 

From this we see clearly that the formation of rings advances with the 
growth of the parr during the course of the summer, and that the scales 
develop with the growth of the fish. ; 

The accompanying figure (Fig. 1) illustrates the scale of the largest 
parr. If we examine it closely we note that all the inner growth rings go 
regularly, and practically without a break, around the whole of the scale. 
It is not until we come to the three outer rings that we find that the ring 
formation begins to be broken. These latter 
rings are only perfect on the anterior portion 
of the scale (the upper portion of the figure), 
and elsewhere they are merged in the edge 
of the scale. It should not be forgotten that 
this fish was killed in the late autumn. 

As a rule rings formed in the summer 
are unbroken around the circumference of the 
whole of the scale, though occasionally one 
may meet with scales of which the summer 
rings are notalwayscomplete. This probably 
arises from the fact that all growths do not 
proceed simultaneously, and that therefore 
the different portions of the scale have not 
always the same uniform rate of growth. It 
is more than likely that this is due to some 
variation in rate of growth in length and in 
girth. In autumn and winter the growth 
generally decreases or ceases entirely, and all ae renee 10 a 3 ee 
the scales I have seen show a similar edge fy gy reg Ba : 
to the one illustrated. This eodbieyw Lap rane Crier 
is also retained during the whole of the winter, and such little growth 
as does take place is shown in the production of narrower rings close 
to the edge of the scale. After the winter, when development begins 
again, the ring formation of the new season does not entirely coincide with 
the last formed rings of the preceding season, and the new growth is shown 
by the formation again of entire and unbroken rings. Itis therefore’as a rule 
easy to recognise the winter rings formed during the period of stagnation 
between the two growth-zones. The chief characteristics of this period of 
stagnation are the pronounced branching or ramification of the rings, and 
also the fact that they are narrower and lie closer together, so that a mag- 
nified representation of a scale shows a narrow and more darkly shaded 
belt. This narrow winter-band has also a different optical refractive 

1—z 


4 THE AGE AND GROWTH OF SALMON AND TROUT. 


power, as will be seen with a microscope by using different methods of 
illumination. 

This difference in the appearance of the summer and winter growth on 
the scales can be easily seen by examining them at different seasons of the 
year, but I considered it advisable to investigate the scales of parr of 
known age. 

From the State Hatchery at Haugsund I obtained examples of parr 
hatched in April, 1907, reared there and finally killed in the middle of 


Fic. 2.—Parr 13 cm. Hau d. Fic. 3.—Parr 13 cm. Hau d. 
Hatched April, 1907. illed Hatched April, 1907. ‘Killed 
middle of December, 1908 middle of December, 1908 (mag- 
(magnified). nified). 


December, 1908. These fish had, therefore, lived for two summers and a 
portion of the second winter. The accompanying figures (Figs. 2 and 3) 
show the scales of two of them. It will be seen that the structure of the 
scales corresponds fully with the seasons during which the fish have lived. 
In the centre of each we find a growth-zone, consisting of relatively unbroken 
broad rings corresponding to the first summer. Surrounding this we find a 
band of narrow branching rings depicting the slackened rate of growth 
during the first winter. Then again surrounding this inner core we find 
similar growth-zones corresponding with the second summer and half of 


METHODS OF INVESTIGATION. 5 


the second winter, and which show a repetition of the characteristics of the 
first year’s growth. I examined altogether ten of these parr, and the 
scales of all showed growth-zones and winter-bands similar to those 
illustrated. . 

Further in the examples I have examined of parr and smolts which 
have grown under natural conditions, and which were caught in spring, 
summer, and autumn, I have found no difficulty in distinguishing the 
appearance of the scales at the various seasons of the year. 


Fic. 4.—Parr 12cm. Softeland May 25, 1909 Fic. 5.—Parr 10cm. Softeland June 11, 1908 
(magnified). . (magnified). 


The three next illustrations (Figs. 4, 5, and 6) depict the scales of parr 
caught in the Softeland River in the Os district, in May, June, and October. 
They show clearly how the summer’s growth is indicated on the scales. For 
example, in Fig. 4 we see that the winter-band, formed during the second 
year of the parr’s existence, lies close to the edge of the scale and that only 
two new broad rings, denoting summer growth, had been formed. The June 
scale (Fig. 5) shows that these broad summer rings have increased in 
number, whereas the October example (Fig. 6) clearly indicates the fact that 
the formation of broad summer rings had ceased, and the narrow branching 


6 THE AGE AND GROWTH OF SALMON AND TROUT. 


winter rings are present, showing the commencement of the third winter of 
the fish’s life. 

The beginning and the duration of winter naturally vary in different 
rivers and districts, and consequently there will be considerable variation 
in the formation of the broad rings indicating summer growth. It seemed 
to me for the present to be unnecessary to devote much valuable time to the 
investigation of fish from numerous localities in order to establish this fact. 
What I considered of more importance, as I have endeavoured briefly to 
prove, was that the growth of the 
parr is very different in summer 
and winter, and that the seasons 
leave ineffaceable marks on the 
scales, which consequently enabled 
one to state the number of winters 
and summers which the fish has 
spent in the river. 


(b.) The Scale after Migration to 
the Sea. 


When the parr becomes a 
smolt and migrates from the river 
to salt water it meets with abso- 
lutely different conditions. In 
what manner are these conditions 
indicated on the scales ? 

In order to illustrate this 
question I give a drawing of por- 
tion of a scale of a young salmon 
(Fig. 7). This fish was caught as 
a smolt with many others at the 

Fra, 6.—Parr 12.em. Softeland middle ot Mouth of the Gula River at the 

October, 1908 (magnified). end of June, 1900. It was then 

between 10 cm. and 15 cm. long. 

Together with others it was placed in a large salt water tank at the 

Trondhjem Biological Station, and kept there until October 18, 1901. 
When it was killed it was 29°5 cm. in length. 

Naturally the surroundings one could give it were not so favourable as 
it would have obtained in the sea, but in spite of this it had grown much 
more rapidly than any parr living at liberty in fresh water would have done. 
In the portion of its scale shown in Fig. 7 we clearly see the three winter- 
bands denoting its life in the river as a parr. Immediately after the com- 
pletion of the third winter the fish was placed in the aquarium, and the 


METHODS OF INVESTIGATION. 7 


rapid growth which then ensued is clearly depicted in broad and strongly 
marked growth rings formed during the first summer in salt water. 
Surrounding these is a band of narrow branching rings corresponding to 
the winter spent in the aquarium, during which period the fish took only 
very little food. Finally we find a wide belt of broad, well-marked rings, . 
corresponding to the growth during the second summer in the aquarium. 
Tt is evident, therefore, that the rings on the scale correspond exactly with 
the conditions under which 
I knew the fish had lived 
from the moment when it 
first came into my hands. 

That the growth of the 
fish referred to above and 
also of the other small 
salmon reared at Trondh- 
jem was considerably less 
than would have taken 
place under natural condi- 
tions is a fact of which 
I have been aware for 
some considerable time, 
but more especially so 
now that Mr. Johnston’s 
investigations have been 
published. 

To put the case briefly, 


he discovered that grilse 
from 45 ecm. and upwards Fic. 7.—Grilse 29°5 cm. 4 unripe. Reared in a Salt 


in length and weighing a Peace te from June, 1900, to October 18, 1901 
kilogram or more had 
spent only one winter in the sea, whereas larger salmon had spent two or 
three, or in exceptional cases four winters in salt water, and also that the 
annual winter bands were as a rule clearly shown. In addition to the 
investigations which he had carried on for several years, he obtained further 
confirmation of his conclusions from the well-known marking experiments 
which were carried out on the River Tay in Scotland. Several thousand 
smolts were marked when migrating in the spring of 1905 by means of fine 
silver wire placed in the dorsal fin.* 

A number of these fish were recaptured, and on examination of their 
scales he was able to establish the fact that the structure and markings 


* Of. W. L. Calderwood, ‘‘ The Life of the Salmon,” Chapter 11. 


8 THE AGE AND GROWTH OF SALMON AND TROUT. 


corresponded exactly with the known life of the fish. ‘Those recaptured 
as grilse in 1906 had two summer-zones and one winter-band formed subse- 
quently to migration, whereas the scales from fish recaught in 1907 had 
two summer-zones and two winter-bands when caught in the spring, and 
an additional summer-zone when caught later on in the year. 

I have found identical summer-zones and winter-bands on the scales of 
Norwegian salmon, and I have also discovered that according to the size of 
the fish they may show from one to four winter-bands subsequent to 
migration. 

It was therefore of great interest to investigate the scales of the small 
grilse which are frequently caught in the mackerel nets in the Skagerack. 
These fish varied in size in May and June from 386 cm. to about 45 cm., and 
the scales show that all these fish have spent one summer, one winter, and 
part of a second summer in salt water. 

It was even of greater interest to discover salmon in a less advanced 
stage of growth in the Sandeid Fjord in Ryfylke, and which were sent me 
by Herr Landmark, the inspector of fisheries. The examples sent consisted 
of nineteen individuals, varying in length between 22 cm. and 27 cm., and 
were caught between July 28 and August 28 in 1908. Their scales showed 
markings similar to the one illustrated in Fig. 8 (Plate I.), which was photo- 
graphed from the scale of a fish 26cm. in length. In the centre is clearly 
shown the poor growth made in the river prior to migration, but 
surrounding this we find a zone of wide and well-marked rings, without any 
branching or contraction in their formation. 

If, however, we compare Fig. 9 (Plate II.), which represents the scale of 
an ordinary grilse 57 cm. long and weighing 1°9 kilos, we find that it has 
two summer zones and one winter band subsequent to migration. Further, 
if we compare Fig. 10 (Plate III.), which is similarly reproduced from the 
scale of a salmon 76 cm. in length and 43 kilos. in weight, we find two 
winter-bands and three summer-zones after migration. Fig. 11 (Plate LV.) 
represents the scale of a salmon of 10°5 kilos. and 96 cm. long, and here 
we find after migration three summer-zones, three winter-bands and the 
commencement of a fourth summer-zone at the edge of the scale. Finally, 
in Fig. 12 (Plate I.), which depicts the scale of one of the largest salmon I 
have been able to get hold of, we find surrounding the central portion of the 
scale, which indicates the life of the fish up to the smolt stage, four, and 
possibly five, winter-bands with the corresponding summer-zones. Now if 
we compare Figs. 9, 10, and 11 we easily perceive that in 9, which was 
caught on July 8, in the Topdalsfjord, the winter-band is some distance 
from the edge of the scale, whereas in 10, which was caught in the same 
place, but on May 27, the last winter-band lies much closer to the edge. 
In 11, which was caught on June 9 in Finmarken, where summer begins 


METHODS OF INVESTIGATION. _ 9 


much later, the last winter-band i quite close to the edge of the scale. We 
also find the same to be the case in the scales of the large fish (Fig. 12) 
caught in the month of May. Itis therefore evident that in Norway also 
the ring formation at the edge of the scale corresponds to the period of the 
year when the fish was caught. After examination and analysis of the » 
scales of several thousand salmon, I find that in the majority of the large 
fish caught at the beginning of the season the last complete winter-band 
lies close to the edge of the scale, whereas in small fish caught at a later 
period the summer-zone outside the previous winter-band is always broader 
and contains a greater number of rings. 

This fact is further illustrated by the following table, which contains an 
analysis of the various positions of the last winter-band in relation to the 
edge of the scale, and is based on the examination of 262 salmon caught 
along the Mandal coast from May to July, 1909. This analysis is based on 
an approximate estimate of the relative width of the summer-zone lying 
between the last completed winter-band and the edge of the scale, and must 
therefore not be taken as absolutely accurate. It clearly indicates, how- 
ever, that the formation and growth of the summer-zone takes place during 
the summer months, and that this zone increases in width as the season 
advances. It also shows that in a number of fish caught in May, and even 
in June, the winter-band lies close to or is actually on the outer edge of the 
scales. 


ANALYSIS OF THE SCALES OF 262 SALMON FROM THE CoAST NEAR MANDAL. 


Number and Percentage of Scales on which the Last Winter- 
band was Situated. 
Number of 
Month. Salmon 
i On the edge. | Near the edge. foo theeiae. Far 00 ure 
End of May _. 22 2 (9%) | 11 (50%) | 5 (283%) | 4(18% 
First half of June. 63 1 (2%) Ms (29%) 51%) | 12(18% 
Last half of June. 84 _ 4 (5%) reid 60 (72% 
First half of July. 93 _ 11 (12% 82 (88%) 


It is most exceptional for any salmon to be caught in the seain Norway 
during the winter months, and it was therefore impossible to obtain material 
in order to ascertain the appearance of the scales during the winter season. 
I therefore requested Dr. Holt to send me from Dublin the scales of a 
number of salmon caught in Ireland during the early spring and summer of 
1909. This material has been examined and analysed as above in order to 
ascertain the position of the last winter-band. The results are given in the 
following table :— 


10 THE AGE AND GROWTH OF SALMON AND TROUT. 


NUMBER AND PERCENTAGE OF SCALES ON WHICH THE LAST WINTER-BAND 
was SITUATED. 


Month. “salmon : On the edge. | Near the edge. amie oe Far by the 

Janua 3 3 (100 
Pevensey 11 11 tog} 
March 20 | 20 (100% 
April . 20 15 752) 3 15%) 2 (10%) 

ay . 12 2 (17%) | 4 (33%) | 6 (50% 
June . 8 1 (12%) | 1 (13%) | 6 (75% 
July 6 — 1 (16%) 2 (384% 3 (50%) 


Here we find that the last winter-band lies close to the edge of the scale 
throughout January, February, and March, and it is not until April that a 
few fish begin to show the commencement of summer growth at the edge 
of the scales. In May, June, and July the summer-zone becomes larger 
and larger, in exactly the same manner as we found to be the case with 
Norwegian fish. 

In my opinion these investigations have made it pretty clear that the 
narrow, close-lying, branching rings are in fact winter-zones, whereas the 
summer-zones are formed of broad, boldly-marked and less branching rings 
which lie further apart. Atany rate, the formation of these two different 
series of growth-rings or zones takes place in the winter or summer half 
of the year respectively. 

If one examines Figs. 9 to 11 (Plates II., ITI., IV.) it will be evident that 
one can easily and unmistakably distinguish the different annual rings 
ata glance. This is, however, not always the case, and a certain amount 
of practice is required if this method of examination is to be employed 
for statistical purposes. In addition, it is necessary that any analysis 
made should be based on as large an amount of material as possible, 
so that in doubtful cases one can obtain assistance from the bulk of the 
specimens examined, and also render the few errors of analysis which may 
arise of little importance by the overwhelming weight of the quantity 
examined. 

One of the chief difficulties and especially to beginners, is the fact that — 
scales may sometimes become slightly displaced in the process of growth, 
and consequently present a distorted picture of the subsequent growth in 
relation to what has previously taken place. In the next place there may 
occur with some individuals secondary checks in the ring formation during 
summer growth, and which are indicated by two or three rings or more 


METHODS OF INVESTIGATION. — 11 


being contracted and closer together. These contractions may be due to 
checks or irregularities in the whole growth of the fish, or to variations in 
the relative rate of growth in length or girth. It is easy to understand that 
a fish which grows so rapidly and which consequently requires such an 
enormous amount of food is very soon affected by any period of scarcity, | 
and it is evident that any such check in growth will be more or less clearly 
indicated on the scales. In the same way a transition from rapid growth 
in girth or thickness to a state of growth relatively more pronounced in 
length would manifest itself by a narrowing of the growth rings at the 
sides, and also in the front portion of the scales. These narrowings or 
contractions in the ring formation which appear in the summer-zone are, 
however, much less distinct than the winter-band, and one soon learns 
how to distinguish one from the other with certainty. That they are in no 
way connected with the winter is evident from the appearance of the scales 
from marked fish of known age, which were examined and depicted by 
Johnston.* 

In order to ascertain more fully the significance of these secondary 
checks, I made an analysis of the frequency of their occurrence in a large 
number of salmon caught in the summer of 1909 in the neighbourhood of 
Randgsund and Flekkero (Christiansand). Out of these I picked out only 
those fish which had one winter-band subsequent to migration. In the 
following table I have divided them into two classes, those with and those 
without the secondary check (see next page). 

It will be seen that the fish whose scales show this secondary check are 
of exactly the same average length as those without it. This could not 
possibly have happened if this secondary contraction of the rings gave the 
same indications as to age as shown by the winter-band. 

There is yet another difficulty which should be mentioned, as it is 
likely to cause considerable trouble to the inexperienced. In scales taken 
from nearly every fish one will find a greater or less number absolutely 
different from the others. Such scales have this remarkable feature that 
the structure of the growth-rings and the season-zones can be easily traced 
from the outer edge of the scale for a greater or less distance inwards 
towards the centre,and as far as this portion of such scale is concerned 
they are exactly like other typical scales taken from the same fish. There 
is, however, this difference, that at a greater or less distance from the outer 
edge of the scale all regular ring-formation disappears, and the central 
portion of the scale, which will be of varying extent as the case may be, 
consists of a large clear space consisting of a number of irregular stripes 


* «Twenty-sixth Annual Report of the Fishery Board for Scotland (for 1907),” 
H. W. Johnston. The Scales of Salmon, Figs, 1 and 2. 


12 THE AGE AND GROWTH OF SALMON AND TROUT. 


Anatysis oF 75 Satmon From Fiexkere and Ranpgsunp, 1909. 


Number of Fish with- Number of Fish with 
ee ae out the Check. ; the Check. 


i 
~J 
Be 


or Or 

o> OU 

_ 
DeFDrFONWNPATOON Ob 


» ert | bo 2 > oro | ro | | | 


Total 47 
Average Length 54°7 cm. 54°7 cm. 


and rings. Up to the present these scales have received but little attention, 
and they have generally been depicted and described as scales with 
“expanded growth centres.” As a matter of fact they are scales which 
have been formed in place of those which have been lost.* As has beer 
previously pointed out, the growth rings are formed only on the outer edge 
of the scale and on the outer surface. It is therefore evident that when a 
scale is torn off or lost rapid growth of an indeterminate nature takes place, 
and fills up the original scale pocket which acts as a matrix, and afterwards 
the formation of the ordinary ring-growth takes place around the cireum- 
ference of this inner plate of indeterminate growth. From that time onwards 
the ordinary ring-growth proceeds in like manner to that which is being 
simultaneously added to the other scales. At the same time the scale 
pocket or matrix of every scale on the fish is simultaneously increasing in 
size. It will be evident that this is the case if we examine a scale, the 
central portion of which has at some period of the fish’s life been displaced 
without being actually lost. The accompanying drawing (Fig. 18) shows 
an example of this. 

The illustration shows the central portion of the scale of a full-grown 


* Attention was drawn to this point by Mr. Hutton in his last paper. 


METHODS OF INVESTIGATION. 13 


salmon. We see the two years comparative poor growth in fresh water, 
and surrounding the second winter-band a few of the broad rings are shown 
which were formed in the richer feeding ground of the sea during the first 
summer after migration. Shortly before the innermost winter growth was 
completed, during the first year of life in fresh water, the scale must have | 
been pushed backwards and sideways, and thus displaced from its original 
position. The posterior edge of the scale has been worn away or re-absorbed, 
and has, as it were, adjusted itself to the shape of the original scale pocket 
or matrix. In that portion of the matrix left empty by the displacement 


Fic. 13.—Salmon, 70 cm. long, 3-9 kilos. Mandal, June 29, 1909 (magnified). 


of the scale we see that no regular ring-formation has taken place, but it 
has been filled up by growth of an undefined and indeterminate nature, 
corresponding to the blank space previously occupied by the anterior 
portion of the scale. Outside this growth ring-formation has proceeded 
in the normal manner. If the scale had been lost the whole of the 
space within the matrix would have been filled with indeterminate and 
abnormal growth. 

The occurrence of such scales is not, however, of importance, provided 
that one is aware of their existence, and care is taken to select for examination 
only such scales as have perfect centres. 


14 THE AGE AND GROWTH OF SALMON AND TROUT. 


(c.) The Scale after the Salmon’s Return to the River and the Formation of 
the Spawning Mark. 


Johnston has clearly and unmistakably shown that the sojourn of the 
salmon in fresh water and the spawning which afterwards takes place may 
have a most remarkable effect on its scales. The scales of spawned or 
spent fish (kelts) which were examined by him were found, in consequence 
of river life and the act of spawning, to be much frayed or worn away, 
either because of the terrible emaciation of the fish or through partial 
re-absorption during the fasting which they undergo in fresh water. This 
wear and tear or re-absorption mainly affects the posterior and upper and 
lower portions of the scales. This is well shown in Fig. 17 (Plate VI.). 
Here we see that large portions of the posterior, as well as the upper and 
lower portions of the scale, are, as if were, eaten away, and to such an 
extent that the posterior portions of a number of the growth-rings are 
broken off. When the fish returns to the sea after spawning and feeding, 
and growth begins again, the new ring formation does not follow the line 
of the old ring formation, but is formed in the usual manner parallel with 
the outer edge of the broken scale, and in some cases one may find the new 
growth-rings running in a direction almost at right angles to the old ones. 
This is clearly shown in Fig. 18 (Plate VII.).. In the gap between the 
broken edge of the kelt scale and the subsequent new growth, a scar is 
formed which is retained throughout the rest of the fish’s life. If it again 
returns to the river and spawns for a second time, and again returns to the 
sea and further feeding takes place, we find a second scar or “ spawning 
mark,” as it has been termed by Johnston. A scale with two such spawning 
marks is shown in Fig. 19 (Plate VII.). 

That this is the case has been fully demonstrated by Johnston from the 
examination of the scales of fish which were marked after spawning. Some 
of these marked fish were recaptured as clean fish, and the scales were sent 
to him for examination. In every instance an undoubted “spawning 
mark” was found on the scales, and he has thus established beyond all 
possible doubt the fact that the ‘‘ spawning mark ” is the result of spawning, 
and that when such a mark is found on the scales of any fish it affords 
unmistakable proof that the fish had previously spawned. 

The number of fish examined by Johnston was, however, too small 
to make it absolutely certain that it was impossible for a fish to 
spawn without a scar or spawning mark being left on its scales, and until 
such proof had been obtained one could not form sound conclusions by 
statistical analysis of the proportion of previously spawned fish to the 
general stock in any river. 

I therefore obtained the scales from a large number of salmon caught 


METHODS OF INVESTIGATION. 15 


in fresh water, and mainly from spawned fish, or those about to spawn. I 
then studied the appearance of the scales, and particularly as to the extent 
to which they were affected by the sojourn in the river and the act of 
spawning. \ “tf 

The edges of every scale taken from a clean well-fed fish caught in the | 
sea, Or just after entering the river, resembles the one shown in Fig. 9 
(Plate II.). Such scales I have classified as ‘“‘ unworn.” Those which on 
examination showed that they were affected by sojourn in fresh water have 
been divided into four classes, viz., “slightly,” “‘ moderately,” ‘‘ much,” and 
‘‘ excessively worn.” ‘These various stages are illustrated in Figs. 14, 15, 
16 and 17 (Plates V. and VI.). The following table gives the results of 
these investigations :— 


Condition of the Wear of the Scales. 


Place and Month; Number - 
an PT Gules Slightl Moder- | Much Exces- 
7 y: ately. i sively. 
2 & 
SE & | Skogan- July 12 7 4 1 a — 
& £2 |varre, Laks-| August 4 — -- 3 1 _ 
S Sp | elv, 1909 | September 2 _ = ~ 2 — 
Pam 


Oy 
| 
_ 
© 
& 


Leerdal October 35 


‘ River, 1909 702 —_— 18 23 20 9 
a 
— 
29 ~=« | Etne River, 

| 5 1907 November 11 | — 1 3 4 3 
& 
ce 

Drammen 15d atm oF MS Ls 15 


River, 1909| December | jo 9 we prs a 


[o>] 
ns 


An examination of this table reveals the following facts :— 

In the fish examined in the summer prior to the spawning season (see 
the examples from Skoganvarre) the scales are found to be more and more 
“worn” as the autumn approaches, On the other hand, of the fish 
examined during the spawning season (the examples were taken from parent 
fish used for artificial hatching) not one single individual has scales which 
are unaffected. The extent to which the scales are worn is considerably 
larger with the male fish than with females, and it is also more noticeable 
during the later months of the year. It is probable, therefore, that the 
wearing of the scales would be even more advanced by the time the spent 
fish left the river as kelts and again returned to salt water and regained 


16 THE AGE AND GROWTH OF SALMON AND TROUT. 


suitable conditions of nourishment. It is, however, the fact that not a 
single salmon had its scales unaffected by its stay in the river and the act 
of spawning, and therefore, of all the fish examined every single one would 
throughout its future existence show on its scales absolute indications of 
having spawned. 

I consider it therefore as absolutely proved that practically every single 
fish which survives the ‘act of spawning, and again regains the feeding 
grounds of the sea, will possess a ‘‘ spawning mark,” and it equally follows 
that the occurrence or non-occurrence of this mark may be utilised as a fairly 
certain indication as to whether a fish has previously spawned or not. 


2. Tue Scaues or Trout. 


The scales of all varieties of trout show a very close resemblance to 
the structural conditions and peculiarities previously described in relation 
to the scales of their near relation, the salmon. I will therefore avoid any 
lengthy description, but will briefly mention a few of the main points which 
are of importance for the investigation of trout scales. 

The formation of the scale begins about midsummer, in the first year 
of its life, and, as is the case with salmon by the formation of a minute 
plate. As this plate increases in size concentric growth-rings are formed 
around the edge in the same manner as with salmon. 

Some examples of young trout caught in August, 1907, in a Nordland 
stream, showed the following maximum number of growth-rings on the 
scales :— 

Of 2 individuals, 3°2—8°3 cm., 1 ring (small plates). 


1 ss 8°5 om., up to 2 rings. 

1 ” 35cm, , 38 ,, 

4 mn 8°7, 3°8, 3°8, 8°9 cm., up to 4 rings. 
1 3°8 cm., up to 5 rings. 


1 ” 40cm., , 6 ,, 

In summer the rings are farther apart, and in winter closer together, 
and more branched, and similar to what was described in connection with 
salmon. 

We can prove this by examining scales from fish caught at different 
seasons of the year, and also by studying artificially-reared fish of known 
age. I have examined several examples of artificially-reared fish, and have 
found that the markings on their scales correspond exactly with the seasons 
during which the fish have lived. As an example I have given two 
illustrations of the scales of these fish (Figs. 20 and 21). 

When we compare the growth-zones and the consequent age of the fish 
as shown by the scales, we find that in each case this is in complete 
agreement with the known life of each individual. 


METHODS OF INVESTIGATION. 17 


It is therefore quite clear that the summer-zones and winter-bands on 
the scales of trout are respectively formed in the corresponding seasons, 
which affect their growth, and that these zones indicate annual epochs in 
the life of the fish. If, therefore, we count the number of these zones, we 
can ascertain the age of the fish. A more lengthy explanation is, I think, 
unnecessary, but I would . 
merely refer my readers to 
the more detailed account 
previously given.in connec- 
tion with salmon. 

As the trout scale is, 
relatively to the fish’s size, 
smaller than that of the 
salmon, and as the majority 
of trout are small fish, it is 
evident that in most cases 
their scales are very small. 
This renders it difficult at 
first to count the number 
of winter-bands, especially 
when we are dealing with 
small fish of considerable 
age. However, a certain 
amount of practice enables 
one to do this accurately. 
An Abbe drawing attach- 
ment is of very great assist- 
ance, for with if one can 
project the enlarged image 


of the scale on to the table PIED Ghar 

. axon. FIG. 20.—Trout 21:5 cm. Biological Station, Bergen. 
by the side of the micro- “Kot three winters after hatching. Killed March 1, 
scope. If we place a strip 1907 (magnified). 


of thin cardboard with its 

left bottom corner in the centre of the image, we can mark on its edge 
with a pencil the exact situation of each winter-band, and we shall find 
that by this method counting is both easier and more accurate. Most of my 
countings have been done in this way. 

In the case of fish which have attained a relatively great age, it may 
happen that the determination of the bands near the edge of the scales may 
be exceedingly difficult. Frequently in such cases the edges of the scales 
have become thickened, and may be seen to contain several bands, without, 
however, one’s being able to ascertain their number. In cases like these it 

8.T. 2 


18 THE AGE AND GROWTH OF SALMON AND TROUT. 


is naturally quite out of the question to determine the age beyond a certain 
number of years. 

When one examines the scale of a salmon one notices at once that on 
migration to the richer feeding grounds of the sea a great change takes 
place in the conditions of growth. The slow-growing scale of the migrating 
smolt appears in the centre of the larger scale of the mature fish, like a 
small island of narrow growth- 
rings surrounded by the wider 
and boldly-marked rings which 
are formed in salt water. We 
can therefore easily distinguish | 
the boundary line on each scale 
indicating the transition to other 
conditions of nourishment. 

With trout, on the other 
hand, which have spent all their 
life under uniform conditions, 
as, for instance, typical burn 
trout, we find the poor growth 
of the scales continued from the 
early stages up to a considerable 
age. 

Other trout, however, whose 
early life has been spent under 
unfavourable food conditions and 
which at a later stage of life may 
have entered into more favour- 
able environment, show on their 
scales a sudden transition and a 


consequent increase in the width 


PEMschad eine cb ae geri oor of the growth rings, and this is 
October 1909 (magnified). similar in character to what we 


have observed in the transition 
stage of salmon. These characteristics we find on the scales of sea trout and 
also of trout from a number of lakes, about which I will later give fuller par- 
ticulars. No trout, however, even under the most favourable conditions, as 
we shall see later, ever grows so fast as a salmon, and consequently the best 
growth-zones found on trout scales are never as broad or as well marked as 
those of salmon. Still,in the majority of cases the differences between 
unfavourable and favourable environment are clearly indicated on the scales, 
and therefore, as a rule, we can determine the period when the transition 
from slow to more rapid growth took place. As an instance of this I would 


METHODS OF INVESTIGATION. | 19 


refer the reader to the characteristic scales depicted in Figs. 22 and 28 
(Plate VIII.). 

The spawning mark, which in the case of salmon we found to be a 
result of and also a clear indication of spawning, sometimes occurs also in . 
the case of trout, but its appearance is generally of a different character. 
In salmon it is the result of the excessive emaciation which this large and 
rapidly-growing fish experiences owing to the terrible fasting and privations 
connected with a sojourn of many months in fresh water prior to and after 
spawning. Most trout spawn amidst surroundings and food conditions similar 
to those to which they are accustomed, and their spawning journey, as a rule, 
is short and unaccompanied by serious privations. Consequently, in most 
of the smaller forms of trout we find no spawning marks on the scales, 
even though the fish are of considerable age and have spawned on many 
occasions. On the other hand, we sometimes find one or more spawning 
marks on the scales of trout, whose growth has been considerable as com- 
pared with the food conditions which prevail in those surroundings where the 
spawning grounds are situated, and whose spawning journey is long and 
arduous. As an instance of this we may mention large sea trout and also 
very large lake trout, such as are found in the Mjosen Lake and also in the 
lakes of Bavaria. Such spawning marks, however, of which an illustration 
is given in Fig. 24 (Plate IX.), as far as I can ascertain, do not always 
appear on the scales as a matter of course as is the case with salmon, 
and, in my opinion, cannot be depended on as reliable evidence of the 
frequency of spawning. 

In investigations as to the age of fish and especially with reference to 
estimates of the rapidity of growth, great care is needed when such spawn- 
ing marks are found ; and, further, if they are difficult to read one must 
endeavour to avoid mistakes, which might easily creep into an analytical table 
if one’s material were not handled in a critical manner. 


8. GENERAL OBSERVATIONS ON THE Usm oF Scaues AS A Mmans or 
DETERMINING THE GRowTH oF F isu. 


If we wish to study the rate at which salmon or trout grow, it is 
necessary to investigate the ages of a sufficiently large number of fish and 
to divide them into year-classes according to length or weight. We then 
find that the various year-classes include fish varying very much in size, 
and, in order to get an idea of the general rate of growth, we must calculate 
the average size or weight for each year-class, and on these averages we can 
base an opinion of the rate of growth. 

For this purpose a large amount of material is necessary, with a con- 
siderable amount of labour for its investigation. As will be seen later, the 

2—z2 


20 THE AGE AND GROWTH OF SALMON AND TROUT. 


statistical analyses which I have drawn up are based upon the investigation 
of a very large number of specimens of both salmon and trout. 

The amount of data necessary in order to obtain reliable statistics 
largely depends on the number of divisions into which our material has to 
be separated in the course of our investigations. 

In the case of salmon the material examined consisted of many 
hundreds of fish, and I consider it beyond doubt that the data obtained are 
sufficient in quantity to be of distinct statistical value. 

So far as trout are concerned my material generally consisted of about 
50 to 150 individuals from each locality, and in order to ascertain whether 
the quantity examined was sufficient in number to avoid error I compared the 
results of two separate examinations from specimens taken from the same 
locality, either simultaneously or in different years. The results are given 
in the following tables :— 


(1) ANALYsIs oF TROUT FROM THE MgiNnBucT River, AGDENES (Cf. Table X-XIII.). 


Average length of the different year-classes incm. Number of specimens in 
No. of each averagein(  ). 
Date. fish. 


2nd. 8rd. 4th. 5th, 6th. 7th. 


July 9,1908 | 51 | 13-9 (29) | 17°5 (10) | 22-7 (5) | 25-7 (3) | 28°6 (3 32 (1) 
July 4, 1909 | 62 | 13°6 (13) | 19°3 (39) | 23-4 (5 : 


Difference . é 03 18 0°7 06 1:9 


(2) ANALYSIS oF TROUT FROM KROKAA NEAR BRONNGY 
(Of. Tables XX XIII., XX XITIs.). 


Average length of the different year-classes in cm. Number of specimens in 
each average in ( 


No. 0 
Date. fish. 


8rd. 4th. 5th. 6th. 7th, 8th. 


July 21,1907| 79 12°5 (2 14°5 "3 17:2 ti 18 ay 21 { 
August 8,1907} 32 12°3 17°2 (11) | 19°3 (7) 20°7 (3 27 (1) 


Difference . e 0:2 0°5 0 1°83 0:3 


The specimens in the third table were caught with nets at either end 
of the lake about 500 metres from the shore. 
An examination of these figures shows that it is only in a few cases 


METHODS OF INVESTIGATION. 91 


(3) ANALYSIS oF TROUT FROM BERGSTSVAND, OSVASDRAGET, IN THE Os DisTRIcT 
(Of. Tables XXV., XXVI.). 


Average length of the different year-classes incm. Number of specimens 
No. of in each average in ( 
Date, fish. 


2nd. 8rd. 4th. 5th. 6th. 


May 10,1909 | 132 7-2 (5) | 13:3 (50) | 169 (44) | 21-7 sh 249 (8) 
May 19,1909 | 155 95 (4) | 139 (73) | 177 20 (24 . 


Difference : ; 23 0°6 0°8 1°7 271 


that we find absolute agreement, and even then it may be merely due to 
coincidence. Whether the examples examined be fairly large or relatively 
small in number our tests invariably show some discrepancy in the average 
length of the different year-classes. For these discrepancies there may be 
various reasons. They may be due to actual variation in the size of the 
fish owing to the catches not having taken place at the same time or locality. 
They may be due to the difference in the number of specimens in each 
sample, or there may have been mistakes in measurement. These dis- 
crepancies, however, are, after all, only small, and the probable error to 
which one is exposed in basing growth determinations on samples of 50 
to 150 individuals does not amount to more than 1 cm. in those year- 
classes which are represented by a few individuals, and in those classes 
which are better represented the error is less, and does not amount to more 
than 5 to 6 per cent. at most in the total length of the fish. 

For exact determination of the rate of growth it is evident that a larger 
amount of material is necessary, but the comparisons above clearly show 
that the examination of even 50 individuals and upwards can furnish results 
which are quite useful in arriving at general conclusions as to the rate of 
growth in various localities. 

I have, however, for various reasons, considered it advisable to ascer- 
tain whether the examination of even a smaller number of individuals might 
not provide equally serviceable results for the purposes of comparison. To 
a certain extent this question is of theoretic interest in considering generally 
variations in growth. It would be of immense practical utility if we could 
take a few fish from any lake and form a reliable opinion as to their growth 
and as to the usual course of growth in that particular lake. If this were 
possible it would naturally make it far easier to obtain a definite comparison 
of the various conditions of growth in different waters. 

I must again insist on the fact that the scales are permanent structures, 


22 THE AGE AND GROWTH OF SALMON AND TROUT. 


and when once acquired are, except in the case of accident, retained 
throughout life. 

It is therefore evident that the actual number of aids on a fish is 
constant, and practically remains the same however old the fish may be. 
As an example I may mention the fact that the number of scales on salmon 
or trout on any particular portion of the body (as, for instance, on a slanting 
line drawn from the posterior edge of the adipose fin to the lateral line) is 
always found to vary within fixed limits in the case of every single trout or 
salmon which may be examined irrespective of age. 

It therefore follows that the scale increases in size with the growth of the 
fish, and that this increase is proportionate to the increased size of the fish. 

Seeing therefore that the growth of the scale is proportionate to the 
growth of the fish, it should be possible to calculate how long a given fish 
was on the completion of each winter of its existence by taking measure- 
ments of the various growth-zones shown on the scales. Such measurements 
would have to be made on the anterior portion of the scale which grows in 
a regular manner and where the periods of winter and summer can be 
differentiated, The measurement should be taken first from the centre of 
growth to the anterior edge of the scale, then from the centre to the last 
completed winter-band, then from the centre to the winter before, and so 
on. On comparing the measurements thus obtained in relation to the total 
length of the fish when caught it should be possible to calculate the length 
it had on the completion of each winter-band. 

I give below a description of the method which I have adopted, and 
which is practically the same as the one that has gradually been adopted 
at the Fishery Directors’ Laboratory for similar investigations of the 
scales of other fish, principally herrings and sprats. The method and 
apparatus have been described in detail by Mr. E. Lea in the “ Publications 
de Circonstances du Conseil International pour |’Exploration de la Mer.” 
It is therefore unnecessary for me to give a full description, and I merely 
give the main outlines of the method of investigation adopted. 

By means of the Abbe drawing apparatus an image of the scale is 
thrown on the table, the long axis of the scale being kept parallel with the 
right-hand side of the microscope, and care being taken that the image is 
always in the same line of orientation. A strip of thin cardboard about 
8 cm. broad and of suitable length is then placed with its bottom left-hand 
corner on the centre of the projected image, and so that the left edge lies 
along the long axis of the scale. On the edge of this strip the position of 
each winter-band and finally the anterior edge of the scale are marked 
with pencil. (See the sketch in Fig. 26.) 

The exact amount of magnification is of no importance as the measure- 
ments obtained are merely relative. 


METHODS OF INVESTIGATION. 28 


The measurements thus obtained have been used for calculating the 
size of the fish at the time when the growth of each winter-band was com- 
pleted. The calculations have been made by taking the measurement from 
the centre to the anterior edge of the scale as equivalent to the total length 
of the fish, and from this the value for each winter-band can be arrived at | 
by a proportionate calculation. The calculation is made by means of an 
apparatus constructed by Mr. Lea and myself, by which the proportionate 
values of each winter measurement are graphically shown, and by its use 
we have been able to accomplish the 
work rapidly and accurately. The 
apparatus and the method of using it 
have been fully described by Mr. Lea 
in the paper mentioned above. 

In this way I have calculated the 
lengths of a number of fish on the com- 
pletion of the first, second, third, &c., 
winter - bands, and the results thus 
obtained are shown in the analytical 
tables of the fish examined by this 
method. 

If one can obtain satisfactory results 
by the adoption of this method the 
advantages are obvious. If, for example, 
I obtain a collection of fifty fish equally 
divided amongst five different year- 
classes, it is evident that by ordinary 
methods I have only ten examples on 
which to base my calculations for the 
average length of each class. On the 
other hand, by adopting this other 
method I am able to make far more Fic. 26. 
observations. If, therefore, this method 
is sound 4a relatively smaller number of examples would be sufficient to 
enable one to draw up an equally serviceable growth-curve, and we should 
be able to avoid having to collect such a large number of specimens, and 
so avoid the enormous amount of time and labour involved in the collection, 
examination, and analysis of one’s material. 

Tam quite aware that one may adduce reasons for believing that the 
length of the scale (the anterior or differentiated portion) may not grow in 
a manner absolutely proportionate to the total length of the fish. Amongst 
other things, I have found that in the case of trout a slight alteration occurs 
with agein the relative size of the head and the tail in comparison with 


24 THE AGE AND GROWTH OF SALMON AND TROUT. 


the scale-covered portion of the body. This difference, however, is not large, 
at any rate in the case of fresh-water trout.* 

There is also some uncertainty in connection with the exact demarca- 
tion of the winter-band, as this is not an exact line, but consists of a 
collection of very narrow growth-rings lying close to one another, whose 
position it is necessary to define. 

It is therefore evident that this method may suffer from several small 
errors, but after some practice and with careful investigation these errors 
will tend to disappear. | 

My main object, however, has been to endeavour to prove by practical 
means whether calculations based on this method of examination will enable 
us to draw up a growth-curve as reliable as one obtained by ordinary methods 
of analysis of age and size, and whether we can accordingly arrive at 
sound conclusions as to the rapidity of growth by the examination of 
comparatively few individual specimens. 

In order to make this point clearer I will give the results of a few 
analyses which I have made. 

Out of a number of examples of salmon from Lister I selected the forty- 
six fish which had spent one winter in the sea, and measured the length of the 
scales from the centre of growth to the anterior edge of the same, and also 
the length from the centre to the boundary of the central portion of the 
scales formed in the river before migration to the sea. By means of the 


* In some fresh-water trout I have measured the total length of the fish, and also 
the length of the scale-covered portion of the body, reckoning from the angle formed 
where the gill-cover leaves the cranium. By dividing the total length of the fisk by the 
length of the scale-covered portion I obtain a coefficient denoting the relative dimensions 
of the two measurements. If no alterations take place in the relative proportions of 
these two measurements this coefficient would (excluding errors) be constant in fish of 

all sizes. 


Total Length in cm. cio 27 lh Coefficient. 
3°58 2°32 1°54 
3°81 2°51 1°51 
3°84 2°52 1°52 
3°90 2°60 1°50 
9-70 6°60 1°47 

12°90 8°70 1°48 
15°00 9°70 1°44 
15°50 11°40 1:40 
21°10 15°60 1°35 
21°10 15°00 1°41 
21-60 15°50 1°39 
22°70 16°90 1°41 
25°00 17°50 1°42 


METHODS OF INVESTIGATION. — 25 


values thus obtained I endeavoured to calculate the length of the fish at 
the time of migration as smolts, and with the following results :— 


Smolt Length in cm. Number of Individuals. © 


— 
1 


Average length 13 cm. Total 46 


The values thus obtained of the length of these fish when they migrated 
as smolts are exactly similar to what we know of the general length of 
smolts when they migrate to the sea. They vary in length, as a rule, 
between 9 cm. and 15 cm., and may occasionally reach 20cm. The average 
length, viz., 18 cm., is a little higher than that which I have found in 
the Trondhjem district, but later investigations have shown that in the 
south the average length of the smolt is rather higher than in the north. 

In the case of trout, as previously mentioned, I have examined a 
number of individuals and have classified them, both by analysis of age 
according to size, and by calculating their size on completion of each 
winter-band by means of measurements taken from their scales. The 
results of these comparative investigations have been tabulated by means 
of growth-curves like the one shown below. 

The abscissa axis is divided into winters and months, with a line for 
every second month. The ordinate axis is divided into centimetres indi- 
cating the length of the fish. For the sake of comparison, both here and 
subsequently in all similar curves and tables, I have assumed that the 
growth of a trout begins on April 1, as this date may be. taken as the 
average date of hatching throughout ‘the whole country. In the same way 
January 1 is reckoned as mid-winter. 

In the diagram shown below, the dotted line has been drawn through 
the points indicating the average length ascertained for each year-class by 


26 THE AGE AND GROWTH OF SALMON AND TROUT. 


classification of age according to size.* It thus represents the growth-curve 
as indicated by one year only, the reliability of which we have already 
investigated, and which I will call the ‘‘ empiric curve.” 

The unbroken line has been drawn through the points indicating the 
values obtained by calculating the length of all the fish examined at the 
completion of the first, second, and third, &c., winter-bands and without 
reference to the year of birth.f This I call the “ calculated curve.” 


om. ry T 
25 : | H+ + 


20 


*K 


15 


10 


1 2 Hee 5 6 7 8 Vintre 


beregnet kurve 
sasscseseeeee EC TMpiTISK Kurve 


Fic. 27.—Comparison between an “ Empiric” and a “ Calculated” Curve of the 
owth of 108 trout caught in the River Chaigijok above Rasti Lombola, 
Eciealy, Finmarken, July 15 to 20, 1909. 


At each observation point on the curve I have put down the number of 
examples on which the average values are based. 

We will now examine a comparison based on the above. 

It is easy to see that there is remarkably close agreement between these 
two curves, so close in fact that it is difficult to imagine any closer coinci- 
dence, and especially so when we consider the numerous small mistakes 
which may occur in connection with the calculations on which these curves 
are based. 

It should also be remembered that neither of these curves should really 
run in straight lines from the observation points, which in the “ empiric 
curve” are during the summer and in the “calculated curve” in the mid- 
winter life ofthe fish. In actuality both these curves should run in waves 
with their minimum points in winter and the maximum points in summer. 
This must, of course, follow from the fact that feeding and growth are much 


* Of. Table XXXYV. + Of. Table XXXvVe. 


—* ——_— 


METHODS OF INVESTIGATION. 27 


less in winter thaninsummer. For this reason alone itis not to be expected 
that these curves, which are drawn in straight lines from point to point, 
would absolutely coincide with one another. 

Kither curve may therefore be said to give a reliable. picture of the 
rate of growth. It is even probable that the one given by the ‘‘ calculated — 
curve” is the more reliable, owing to the fact that it is based on a far 
larger number of observations, and especially in the case of the earlier 
year-classes, which are the most difficult to obtain in their natural 
state. 

I have drawn up similar comparisons of “ empiric’”’ and “ calcu- 
lated ” curves for severallocalities. In each case I have found remarkably 
close agreement, but I do not consider it necessary to reproduce them 
here in the form of illustration. Anyone who wishes can easily chart the 
curves for himself from the average figures which will be found worked 
out in the various tables, as for instance in Tables XXII., XXIIz., XXIII., 
XXIIs., XXXIV. and XXXIVs, 

In onder to show clearly to whatan extent “ calculated” growth-curves 
can be founded on a comparatively small amount of material we will 
examine more closely the material on which the “calculated” curve for 
Chaigijok is based. (See Table XXXVs.) 


Calculated Average Length in cm. on the Completion of each Winter-band. 


Chaigijok above Rasti Lombola 
July 15—20, 1909. 


1 2 3 4 5 6 § 8 


First 33 fish 10—17 cm.|5 (33) 
Next 33 ,, 17—20 ,, |4°7(33 


(33) 12°83 (24) | 14-2 (19) | 15:5 (2) 


9°3 
9°3(33) | 13-2 (33) | 16-3 (32)| 17-8 (17 
ns 32 ,, 20-28 ,, |4:9(32) |9°7(32) | 13-8 (32) | 17°5 (32) | 18-9 (30) | 20°9 (15) — 
Last 10 ,, 23—26 ,, |4-9(10) |9-7 (10) |13°8 (10) | 15-9 (10) | 19:8 (10) | 22-2 (10) | 23°8 (7) 24-2 (2) 
Allthe 108 ,, 10—26 ,, | 4:9 (108) | 9°5 (108) | 13-2 (99) | 16-4 (93) | 18°6 (59) | 21-4 (25) | 23-8 (7) | 24-2 (2) 
10 ,, measuring 
14—25 cm.|5 (10) |9°6(10) |13°1 (9)|16-1 (8)}19°1 (6)]20-7 (2) | 23-2 (1)| 24-3 (1) 


In the accompanying table I have divided the examples into four groups 
of various and increasing sizes of fish. For each of these groups the 
average figures have been calculated of the length of each year-class. In 
addition I have given the average length for each year-class based on an 
examination of all the 108 individuals under investigation. Finally, I have 
selected at random* ten fish out of the whole sample, and the average 
length figures for these are given separately in the bottom line in the table. 


* This selection was made by a lady who had no knowledge of the subject, and who 
was merely asked to cross out 10 of the total of 108 numbers. The numbers chosen were 
11, 19, 31, 37, 50, 61, 70, 84, 92, and 105. 


28 THE AGE AND GROWTH OF SALMON AND TROUT. 


The number of observations on which each average figure is based is given 
in brackets. 

If we compare the average lengths for each of the groups into which 
our material has been divided with the average lengths based on the whole 
of the 108 fish, we find the following :—Taking chiefly small fish for our 
calculations, such as are contained in the first three groups, we find that 
the average length very closely approximates to that based on the whole of 
our material, at any rate as far as the younger year-classes are concerned. 
It is only in the later years, and especially in the last year, that the figures - 
are less reliable. It will further be noted that as we include larger and 
larger fish in our investigations the more the figures for the later years 
coincide. If, however, we compare the figures based on the ten largest 
fish, and also those of the ten selected at random, together with the average 
of the whole of the 108 fish we find most remarkable agreement. The 
differences only amount as a rule to a few millimetres, or exceptionally to 
one centimetre. It is evident, therefore that the errors which might arise 
from basing one’s calculations on only a small amount of material are not 
likely to exceed 5 or 6 per cent. 

It appears, therefore, that one would be justified in basing calculations 
as to the rate of growth on only a small amount of material, provided, | 
however, that the individuals are fairly distributed amongst the various | 
sizes of fish occurring in a lake, or that they are selected from a few of 
the largest fish to be found there. | 

A careful analysis of other similar calculations shows on the whole the 
same characteristics as the material from Chaigijok, and I give here a 
similar classification of fish taken from the Sanna Lake, near Harstad.* 

(See Table XXXTYs.) 


; inter-band. 
pe Re ECAR Calculated average length in cm. on the completion of each winter d 


Harstad, 


August 8, 1909. 1 2 3 4 5 6 7 8 9 10 ll 
First 83 fish 

13-24em. . | 5°4 (83)| 8°8 (22)/13 (22) | 17°6. (14) | 20°8 (4) 
Next 383 fish 

24-29 em. | 4:3 (83)| 83 (83)|12°5 (88)/19 (33) | 23°6 (20) | 25:5 (2) 
Next 33- fish . 

29—84em. | 4°8 (88)| 9-3 (83)| 18-3 (88) | 18-1 (38) | 25-2 (38) | 29°4 (17) | 32°5 (2) 


Last 16 fish 
84—49 cm. ° 
All the 115 fish 
13—49cm..__. | 4°9 (115) | 8°9 (108) | 18 (104) | 18°4 (96) | 24°6 (73) | 30°5 (34) | 36-2 (12) | 41°7 (7) | 44°4.(5) | 46 = (2) | 48-2 (1) 
11 fish measuring 
16—47 em. -|4°9 (11)|9°7 (10)} 142 (10)}18 (9)/26 (5)|81°5 (4)} 42-2 (1) | 43°8 (1) | 45°38 (1) | 46°41) 


4-9 (16)|9°1 (16)|13°4 (16)|19 (16) | 25°7 (16) | 32°4. (15) | 37 (10) | 41°7 (7) | 44°46) | 46 (2) | 48°2 (1) 


This analysis, in its general features and results, is absolutely similar 
to what we found in our classification of the fish from Chaigijok. Again 


* The fish taken at random were selected in the same way as those from Chaigijok. 
The numbers were as follows: 9, 22, 30, 38, 50, 62, 69, 81, 90, 102, 113. 


METHODS OF INVESTIGATION. | 29 


we find that the last three groups agree most closely. With one solitary 
exception the differences are, as a rule, very small, and hardly ever exceed 
a small percentage of the average length of each year-class. Between the 
average of the whole of the material examined and the corresponding 
averages for the eleven fish selected at random, it is only in one instance, | 
viz., the seventh class, that we find a difference of about 16 per cent. This 
exception may, however, be due to the fact that the figures for the last four 
winters of the eleven fish group are based on one single individual, and 
cannot, therefore, be taken as an average representation. 

The results obtained from these investigations seem to me to prove 
sufficiently that we can obtain fairly reliable illustrations of the rate of 
growth from calculations based on a comparatively small amount of 
material. It is hardly necessary to add that the specimens should be 
selected with judgment, and also with some knowledge of local conditions 
and of the maximum size of fish frequenting the waters under investiga- 
tion. The results should also not be pressed too far or without allowance 
for possible sources of error. Still, it is important to know that for all 
practical purposes it has been found possible to form a fair idea of tne rate 
of growth of fish in any particular locality by merely examining a 
comparatively small number of individuals. 


CHAPTER IL 


ON SALMON, 


Tue material on which I have based the statistics of my investigations 


of the salmon’s age and growth is as follows :— 
1. Parr and Smolts. (Cf. Table I.). 


1908. Skaugdalselv Rissen . 52 fish. 
Orkla - 104 ,, 
Oselv ‘ F ; 59 ,, 

1909. Laksely, Finmarken . 2 Ware 

Total . 2 286 fish. 
2. Salmon and Grilse. (Cf. Tables III.—XIIL). 
1908. Neighbourhood of Christiansand, Season 
1908 ; ‘ 4 : . 676 fish. 
Moltuen Icehouse, Imsterfjord, Season 1908 261 ,, 
Orkla (lower water) Season 1908 244 ,, 
East Finmarken, July 1908 89 ,, 
Total 1908 . 1,270 fish. 
1909. Neighbourhood of Christiansand, Season 
1909 . c ; ; ; ; 1,614 fish. 
Moltuen Icehouse, Imsterfjord, Season 1909 184 ,, 
Bugenes, South Varanger, up to com- 
mencement of July, 1909 285 ,, 
Total 1909 . 2,088 fish. 


In addition I have collected a few other examples from various places. 
All of these have been analysed with reference to the comparative length 
for age, and also in most cases as regards the weight. The results of this 


analysis are given in the tables in the Appendix. 


(1.) Tue Acre anp CHARACTERISTICS oF Parr AND SmoLrs 


Prior to MicRArIon. 


In Table I. I have drawn up the analysis of all the parr and smolts 
which I have examined. I have investigated as to the size, age, sex, and also as 


ON SALMON. 31 


to how far the sexual organs were developed, i.e., whether the fish would 
spawn in the following autumn. Disregarding the question of size they are 
divided in the following table according to their age and the state of the 
sexual organs. : 


Of these the following had completed 
\3 
Faed 1 Winter. 2 Winters. 3 Winters. 4 Winters. 5 Winters. 
oA 
District. Bg 
ga| ¢ + hig BOA ati = Seats Uk ik AP Rb erp P ge RRs LU 9 ee Nis 
é 3 E E : E 
n.|on) x. lon) |m.jor}mfor}" | e,|on) x. jo) * |e. on) a. jon) |e jon nJon! 
Oselv 59|1|)8|—|17|26| 9] 8|—| 14] 31 EA By SEG eee | RO LR Hey AY SVR) (Pica Pe PA OS ee 
Orkla web) et) 8] eo) | Babee paeter lst ot} er lirp— pape} — poe pay ee 
Laksely .| 71} —1—{|—|—|—|—| 2]/—] 118 1/—{1] 4})32] 2}/—j20/68}1}/—|—|— 


UR. Unripe, i.e., sexual organs not matured. 
R. Ripe or ready to spawn in autumn. 

As the above fish were caught between July and September, it is 
evident that the age when migration would take place would have to be 
increased by another winter, as they must spend another winter in the 
river before they could migrate as smolts in the following May or June. 

As regards the relative proportion of fish of different ages the table 
cannot give any conclusive evidence, since all the fish were caught either 
with fly or hook. For that reason the smallest class of fish would not be so 
fairly represented as the older and larger fish. In most places it is 
impossible to catch the fish in any other way. The same objection applies 
also to drawing any conclusions as to the relative size of the various ages, 
which one can, however, study with the help of the tables in the appendix. 

Our table shows us two things clearly. | 

First, we must note a very distinct tendency for the fish to remain 
longer in the river in the northern regions than further south. We have 
further confirmation of this, as will be seen later from the other tables. 

Secondly, on investigating the sexual organs we find a remarkable 
circumstance. The female fish were all without ova, but of the males a not 
inconsiderable number were ripe. From the swollen milt it was evident 
that many of these would spawn in the ensuing autumn. 

That these small male fish were really ripe was confirmed by examining 
similar male fish in the late autumn. They then had free running milt, 
which on microscopic examination was found to contain living spermatozoa. 

The table also shows clearly in what proportion the sexually developed 
male fish are distributed among the various year-classes. 

We see that in the Oselv there was only one ripe male among the fish 
which had completed their first winter, whereas among the two-winters fish 


82. THE AGE AND GROWTH OF SALMON AND TROUT. 


there are about as many ripe as unripe. Among the three-winters fish all 
the males are ripe. 

In the Orkla some of the two-winters fish are ripe, and among the 
three-winters fish there are as many unripe as ripe. . 

In Finmarken these conditions are postponed until a year later. With 
reference to the age at migration, the only conclusion we can draw from the 
table are as to the maximum age up to which the parr remain in the river. 
In order to find out the age of migration it would be necessary to catch the 
smolts when migrating, and to study their age. Here one immediately 
meets the difficulty, that in certain cases it is a question whether the fish -’ 
has or has not the migratory colouring. In my opinion it is therefore a 
safer method to obtain one’s information by examining the central portion 
of the scales of larger fish, and this is the method I have adopted. — 

With reference to the time of the year when migration takes place, my 
previous investigations, both with salmon and sea trout, pointed to the fact 
that the main period of migration is during the spring, when the rivers are 
flooded with melting snow. At the same time during the summer one could 
find fish with the migratory dress (i.e., with more or less silvery coating), 
especially in the lower reaches of the river. I concluded, therefore, that 
migration also took place during the course of the summer. 

Further investigations showed that “ silveriness” is not an absolute 
proof that migration will immediately take place, for I have found amongst 
other things that male fish with well developed'milt, caught during the summer, 
can be fairly silvery in colour. The assumption of the silvery coating can 
thus apparently begin a long time before migration. 

In the Trondhjem district the largest migration took place in June. 
Further south May seems to be the most important month. 

In the Oselv in 1909 I fished with a net to catch smolts for marking. 
For this purpose I chose a suitable place in the river about 100 metres long. 
The net was sufficiently long to sweep the whole breadth of the small river, and 
this place was fished for a considerable time almost every day. The smolts 
were migrating continuously, and at the height of the run no falling off 
was noticed in their numbers, even though we made cast after cast in the 
same water, and school after school came down through the same reach. 
The netting began on May 10, whentit was noticed that there was a 
considerable number of bright and large fish migrating, but towards the 
end of the month the catch fell to a minimum in spite of all attempts that 
were made. The numbers caught were as follows :— 


May 10 and 11 ; : . 613 fish. 
13 ,, 15 ‘ 5 » «) Sera 
16.4 23g , ‘ oi SLA 


CY g armuaaes S ieee 2 


ON SALMON. , 338 


The few which were forthcoming at the end were nearly all quite 
small, and of the typical bluish brown and copper coloured shades, which 
characterise the growing parr. The migration of the class of fish caught 
in the earlier part of the month was apparently over. We tried in other 
places but we did not find it worth while continuing. 

It is therefore not probable that there is any large migration during’ 
the summer, though odd fish may occur. Examination of the central 
portion of the scales of larger fish also shows that only a few have any 
signs of summer growth in the river after the last winter prior to 


migration. 
2. SALMON AFTER MIGRATION. 


As I mentioned before, in dealing with the methods of investigation 
which I have adopted, with the help of a microscope the scales reveal the 
following facts. 

We can easily distinguish the boundary line which marks the entrance 
into salt water. If we study the central portion of the scale (the river life) 
with higher magnification we can count the number of winters the fish has 
spent in the river. For example, compare Figs. 9b, Plate II., 10b, 
Plate III., 11b, Plate IV., which represent enlargements of the oenteal 
portion of the scales. 

Further, it can be seen how many winters the fish has completed in 
the sea after migration, and also whether the fish has a spawning mark 
or not. 

As an example of the methods I have adopted let us examine Table VIII., 
which contains the analysis of 1612 salmon from Christiansand in the 
season of 1909. As will be seen from the table, I have arranged the fish 
according to their length in centimetres, and in a separate column I have 
noted how many fish belong to each class. 

I have examined the scales of each class microscopically, and have 
determined how long each fish has lived in the river prior to migration, 
and how long it has lived after migration, and also whether it has previously 
spawned (i.¢., whether it has a spawning mark). According to the results 
of this examination the fish have been classified under the various headings. 
Fish which are returning to spawn for the first time are denoted in ordinary 
figures, but those which show a spawning mark, and which have conse- 
quently spawned on a previous occasion, are denoted in brackets. In the 
same way each centimetre or length-class is dealt with in turn until the 
whole are completed. 

The headings of the table are arranged so as to make it clear whether 
the fish have completed one, two, three, four, five, or six winters subsequent 
to migration. Under each of these main headings the fish are again divided 

8.T. 8 


34 THE AGE AND GROWTH OF SALMON AND TROUT. 


by sub-headings, showing whether they migrated when two, three, four, or 
five winters old, and how large they were on the date of capture. In the 
final column is given the size and the total number of fish caught of each 
year-class divided according to the number of winters completed subsequent 
to migration. 

At the foot of the table we have the total of the various sub-divisions, 
together with their average length. 

From this table we can read the following :— 

The number of years of river life before migration. 

The years of sea life before spawning. 

The relative occurrence of previous spawners. 

The average length in centimetres of the various age-classes. 

From the arrangement of the dating at the head of the column we can 
also readily tell the year when the fish were hatched. 

In a similar manner the same material has been divided and arranged 
according to the fish’s weight (see Table XI). 

All averages are reckoned from the original tables, which were after- 
wards arranged for printing purposes, so that the length classes were in 
divisions of 8 centimetres, and the weight classes of 7 hectograms. 

In the same way the whole of the material has been arranged in 
separate tables for each locality. 

From these tables we can obtain information on the two following 
points in the life history of the fish which I now propose to discuss 
separately, and which I shall endeavour to further elucidate with the help 
of other material in my possession. 


(a.) The Age of the Smolt at Migration. 


In the table below I give the total number of fish from each of the 
various districts, examined in 1908 and 1909, and in the separate columns 
is shown how many of these migrated after an age of two, three, four, or 
five winters. 


1908. 
Of which on Migration the following Number and Percentage had 
’ Number Completed 
District. Examined. 

2 winters. 8 winters. 4 winters. 5 winters. 
Christiansand -| 667 223 (33°5 %)| 408 (61 %) 34 (5 % 2(4 9 
Tréndelagen . .| 498 66(18 %)| 359(72% 68 (14 % 5 (19 
Ost-Finmarken . 87 7 (8 %)|  52(60% 24 (27% 4(5% 


ON SALMON. 35 


1909. 
Of which on Migration the following Number and Percentage had 
‘ Number mole 
District. Examined. : 

2 winters. 8 winters. 4 winters. 5 winters. 
‘Ohristiansand «=. | -: 1612 || 296 (18 %)| 1097 (68 2» 207(13 %)| 12(1 %) 
Trgndelagen . , 184 11 (65 % 124 (67 % 48 (26 %) 1(4 ) 
@Ost-Finmarken . 284 7 (25% 133 (47 %) | 124 (48°5 %) 0(7 %) 


A close examination of these tables shows that the age of the smolts at 
migration varies between two and five winters. In the south the smolts 
are generally young, but the farther north we go the more pronounced is 


the tendency for the fish to remain longer in the river before migration. 


This is clearly seen from a comparison of the percentage of the different year- 
classes, and we also find that in both tables the main features are identical. 

It will be remembered that it was previously pointed out that a direct 
examination of fish caught in the rivers in the same districts (see p. 31) 
showed that the river life tended to lengthen as we proceeded northwards, 
and we have now been able to confirm and strengthen this theory by other — 
methods of investigation. 


(b.) The Length of the Salmon’s Life after Migration. 


The two following tables show in condensed form the results of my 
analysis of the salmon and grilse caught in 1908 and 1909 :— 


1908. 
Number Of which the following number had completed after jiterios 
District. of fish 
Examined. 1 winter. | 2 winters. | 3 winters. | 4 winters. | 5 winters. | 6 winters. 
Christiansand . 676 239 | 366 (17) | 26 (25 (3) — _ 
Trgndelagen . : 505 47 | 318 (2)} 127(9 1 (1) ~- — 
@st-Finmarken . 89 16 21 48 (1 2 (1) no — 
1909. 
Number Of which the following number had completed after migration 
District. of fish 
Hxamined. 1 winter. | 2 winters. | 3 winters. | 4 winters. | 5 winters. | 6 winters. 
Christiansand .| 1612 618 | 855 (34) | 51 (49) (4) — (1) 
Trondelagen . P 184 44 75 54 (4 (5) 2 
Ost-Finmarken .| 284 — 24 227 (7 3 (18) 5 — 


3—2 


86 THE AGE AND GROWTH OF SALMON AND TROUT. 


Maiden fish which have not spawned are shown in ordinary figures; 
those with a spawning mark are placed in brackets. 

These tables tell us several things of great importance. 

Firstly we notice that the salmon does not live many years after 
migration. Most of the fish have spent from one to three winters in the sea. 
A salmon, whose scales show more than four winters after migration, is an 
extraordinary exception. 

In the same way the tables show us that the large majority of the fish, 
on which our fisheries depend, consists of fish which have not spawned 
before and which are entering the river for the first time to spawn. It will 
also be noticed that these maiden fish are not all of one age, but may 
have spent from one to four winters in the sea before they attained sexual 
maturity. 

This clearly shows that the salmon, which in each year are the material 
for our fisheries, and which are making their way up to the rivers, are not 
the whole of the fish in existence. They form only a portion of the various 
year-classes to which they belong, a portion which is on the point of becom- 
ing sexually mature, and which, as it were, has broken away from the rest 
for the purpose of spawning. This is made even clearer by an investigation 
of the sex of the fish. It was impossible for me to include such investiga- 
tions with my analysis of age ona large scale, for it would have necessitated 
cutting each fish open, the expense of which would have been prohibitive. 
I have, therefore, been compelled to restrict myself as far as this point is 
concerned to investigations on a small scale. 

In Table XIV., I have given the results of such investigations. I cut 
open and examined the sexual organs of forty-eight small salmon caught in 
the district between Trondhjem and Finmarken in the beginning of July. 
All the fish which had completed only one winter in the sea, as will be seen 
from the table, were males. The hen fish were only to be found when I 
came to examine fish which had spent two winters in the sea. 

As will be seen from all the tables the fish which have spent one winter 
in the sea vary in length between something over 40 centimetres and about 
67 centimetres, and by measurement alone we were therefore able to dis- 
tinguish a good many of the one winter old fish (see for example Table VIII.). 

Now we have a number of measurements taken from a good many 
rivers of the size of parent fish, which had been obtained for hatching pur- 
poses, and which after spawning had been used for marking experiments. 
In these measurements the sexes have been carefully distinguished. Herr 
Landmark, the Government Fishery Inspéctor, has kindly lent me his list 
of these measurements. 

With the help of these I have compiled all the available measurements 
relating to the size of each sex from the Aaensire, Laerdal and Drammen 


ON SALMON. 37 


rivers (see Tables XV. and XVI.). These tables show clearly that an over 
whelming majority of the fish under 58 centimetres length are males. In 
some years there can be more females of this size, but over a period of years 
far and away the larger number are males. As will be seen, fish of this 
size consist almost entirely of those which have spent only one winter in 
the sea, although there may be some fish of two winters age among them. 
It is quite possible that it is just these latter fish which are females. 

We can therefore safely conclude from these tables that the salmon 
which we catch and which have only spent one winter in the sea are almost 
entirely males. 

And, when this is compared with what has previously been set forth, 
it provides us with a striking proof that the salmon which, after one, two, 
or three winters in the sea, approach the coast, and which form the material 
for the fisheries in our waters, form only a portion of the year-classes to 
which they belong. They consist of that portion torn away from the others 
by force of the spawning instinct. 

Let us now again examine the tables on -p. 35. If we compare the 
proportion of maiden fish to those which, as seen from the spawning mark, 
have previously spawned, we find that the number of the former is far and 
away the larger. If we arrange the latter in the form of percentages for 
the various districts in the two years under examination we obtain the 
following tables :— 


Percentage of Fish with ‘‘ Spawning 
Mark.” 


1908. 1909. 
Christiansand ‘ ; 8 °/, Sy 
Trondhjem .  . . ii 6°, 
Kast Finmark . ; 2°, 10 °%/, 


As is clearly shown, only a very small portion of the whole have 
spawned before and are returning to spawn for a second time. 

It would appear, therefore, that the operation of spawning is a factor 
which has serious effect in shortening the fish’s life, or, indeed, in abruptly 
ending it, and this is easily understood when one thinks of all the dangers 
the fish has to pass through during its spawning journey, and among which 
by no means the least are the snares and traps of mankind. The violent 
changes of conditions to which it is subjected during its long journey, 
during the long fast in fresh water, and during the labours in the actual act 
of spawning, are bound to be fatal in their effects. Many die, many are 
like living corpses when they again make back to the sea, and they must 


88 THE AGE AND GROWTH OF SALMON AND TROUT. 


undoubtedly remain for a long time in an emaciated and weak condition 
before they reach the surroundings which can provide them with the 
powerful nourishment which they require.* 

The importance of the spawning journey as a factor of destruction in 
the life of the salmon is shown more clearly when one takes into considera- 
tion the number of fish whose scales show two “spawning marks.” In the 
whole of my material, which consist of 8,350 individuals, I have found only 
three specimens whose scales showed two spawning marks, that is to say, 
only three individual fish which had survived the second spawning. 

In order to throw further light on this question I have examined my 
material with a view to discovering the period when the spawning mark is 
formed. 

Those salmon which in the summer approach our fjords and rivers, 
and whose scales show one, two, three, or more winter-bands after migration, 
spawn in the autumn or winter, and consequently are in the second, third, 
or fourth or corresponding winter after migration. The winter in which 
spawning occurs can, as has been previously shown, be determined by 
examination of the scales, with possibly a few exceptions. After a series of 
investigations I have drawn up the following tables :— 


1908—1909. 
Number and Percentage of Fish whose Scales showed a 
Number of wning Mark in Winter a’ ion. 
Be 8 ish th Spa @ Mark in Winter after Migrat: 
Mark. ond. srd. 4th. 

Christiansand 183 124 (98) 9 (7) 
Trendelagen 25 14 (56) 9 (86) 2 (8) 
Mst-Finmarken . 81 8 (26) 20 (65) 8 (9). : 


This table shows us first that the salmon’s age on the first spawning 
is generally greater in our examples from northern than from southern 
districts. Secondly it makes it clear that it is chiefly the fish which have 
spawned at an early age that return to spawn for asecond time. The great 
majority of the fish which in the summer are two and three winters old 


* The following note is given as an illustration of the food taken by salmon. In the 
year 1909, between June 30 and July 2, I opened and examined the stomachs of 49 grilse 
caught between Trondhjem and Finmarken. In 26 cases the stomachs were empty or 
contained only an indefinable pulp. In 17 fish I found herrings up to 20 cm. in length, 
and in some cases the stomachs were absolutely crammed with these fish. In three cases 
the contents consisted of capelan (Mallotus villosus). In two cases I found the stomachs 
were full of Euphausids, partly mixed with pelagic amphipods. In one case the stomach 
was crammed with the pelagic amphipod (Parathemisto oblivia). 


ON SALMON. 89 


and which spawn for the first time in their third and fourth winter, very 
seldom reappear in the form of fish with a spawning mark. 

This evidently points to the fact that few of the older fish survive 
more than one spawning. 

With reference to the duration of time which elapses before a fish 
which has once spawned again returns to spawn, the study of the scales 
with spawning marks affords useful information. With certain reservations 
one can read from the scales how many summers and winters have elapsed 
since spawning occurred. To illustrate this I have drawn up the following 
table, which shows the length of absence after the first spawning. These 
figures must not be regarded as absolutely correct, but they are sufficiently 

so for comparative purposes :— : 


1908—1909. 
Number of Number and Poneeee Sp pest eee Absence after the 
District. Baaentnn 
Mark. _1 summer. 2 summers. 3 summers, 
Christiansand . 183 | 52 (88) 79 (60) 2 (2) 
Trendelagen 25 6 (24) 19 (76) 
Mst-Finmarken . 81 1 (8) 28 (90) 2 (7) 


Here, too, we seem to be able to trace a difference between the northern 
and southern districts as regards the variation in the fish’s absence after 
the first spawning. 

Let us now sum up briefly what we have learnt from our investigations 
as to the age of the salmon after migration. 

Everywhere throughout the country where our investigations have 
been conducted we find that our material is composed as follows :— 

By far the largest majority consists of fish which have never spawned 
and which have remained in the sea from one to three and exceptionally 
four winters, and which are therefore in their second to their fifth summer 
after migration. 

These fish spawn in the second to the fifth winter after migration, and 
apparently only a portion of them—chiefly composed of the younger fish— 
survive the spawning journey and the actual spawning. This little band of 
survivors returns again to the sea, and some of them after the lapse of one 
year, others after two years, and very few after three years interval, return 
to spawn for the second time. Only an infinitesimal portion of these, 
about one in a 1,000, have shown that they have returned to spawn for the 
third time. 


40 THE AGE AND GROWTH OF SALMON AND TROUT. 


Let us now consider :— 


(c.) The Salmon’s Growth after Migration. 


Tables III. to XIII. contain all the information which our investigations 
are able to give concerning this question. If we examine the different tables 
we find that the individual fish which belong to each year’s class vary very 
much in size within certain limits. At the same time these variations 
arrange themselves in more or less regular Galton curves. 

In order to obtain a useful illustration of the growth which each single 
age-class has made, we must turn our attention to the average sizes, which 
have been calculated for each age-group, both as regards length and weight. 

By means of these averages I have compiled the following tables of the 
results of my analysis for the years 1908 and 1909. 

The tables contain the average length and weight which I have found in 
my analysis of salmon which had lived one, two, or three winters subsequent 
to migration. Maiden fish and those with spawning marks are treated 
separately. In a separate column for each year’s class I give the number 
of fish on which the averages are based. Everyone can therefore judge for 
himself how much reliance should be placed on them. 

I have omitted from the tables fish of more than three winters after 
migration, as their number is so small that an average based on so small: 
an amount of material would have but little value. 


Number and Average Length and bi gun of Fish which after Migration 


have Liv 

Locality. Year. 1 winter. 2 winters. 8 winters, 

Le Weight L Wei Li h Weigh 
No. ana in Baoan: No. Pye ies in hen rd No. npg in kena ol 
MAIDEN FIsH. 

wad 1908] 239] 56-2 } 168 | 366] 73:2 | 39°7 | 26] 98-7 | 111°6 

Christiansand -|j999| 618| 54:9 | 17-1 | 855| 73 41 51) 91°3 | 89-4 

1908} 28] 549 | 17:9 |166| 762 | 50°9 | 56] 95:6 | 105-9 
Moltuen . -/ 1909] 44| 561 | 19:5 | 75| 754 | 49:1 | 54| 94-9 | 100°8 
Geile to. 71 19061 - 307° Be 18:2 |151]| 81 59 71| 969 | 105 

mae i , | 1908] 16} 583 | 20:5 |. 21) 76:8 | 49-1 | 48] 93:3 | 963 
East Finmark -/j999/ —| — — | 24] 73-9 | 44:2 1227] 891 | 79-9 

With Spawnine MARKs. 

“Pe 1908} —} — — | 17] 655 | 27-4 | 25] 74 411 
Christiansand .|j999/ |  __ — | 34] 61-2 | 299 | 49] 751 | 42-7 
see yooa Sk La 3] 605 | 255 | 7| 82 67°5 

ec Be ‘O04 Siti evs ae) eee a 4°] 888 18°5 
Orkla. -) «) {24 2008} —— [2s — a3 |, Same Crees tek, Re 2] 88 83°5 

: OG eae igs ets. | od hese ae 1| 79 53 


ON SALMON. | 41 


If we examine this table we find that the average weight we have found 
for the various age classes is different in the different localities. If we 
disregard the question of the correctness of these average figures, and also 
the fact that the fish in the corresponding age-class may not all have been 
caught in exactly the same period (perhaps also may not have been hatched 
or may not have migrated at exactly the same period of the year),* we still 
find that salmon of correspondin e-classes are not of the same size 
throughout the whole country. Nor ay of the same size in different 


years. | 
If we put this in tabulated form it becomes clearer. 


Fish wirnout Seawninc Marx. che 
Variation in the Average Weight and es of Fish which after 
Migration had Live 
1 Winter. 2 Winters. 8 Winters. 
. 1908 54°9—58°3 73°2—81 93°3—98°7 
ORE A GI.) pong te Ree 56 73 —754 | 891—94°9 


nee 1908 | 168—205 | 397—59 96-3—111°6 
Weight inhectogr.| jo99 | 47-1195 | 41 —491 | 79°9—1008 


An exact determination of the growth of salmon for the whole country 
can therefore not be obtained on the basis of this material. We cannot do 
more than say that the growth appears to vary within the limits mentioned 
above and shown in this table. 5; 

If we examine the table on page 40 we find also that the relation between 
length and weight is different in different localities. Herr Landmark has 
previously endeavoured to demonstrate this fact by weighing and measuring 
salmon whose age was unknown. Now that we can separate the fish into 
groups according to their age this difference is confirmed, but it is not a 
difference of great magnitude. 

It was hoped that one could establish the fact of race characteristics 
with the aid of the variations which a comparison of weight and length 
showed to exist in various localities. If we examine the table carefully it 
appears that there is not much probability of this. 

If we examine the one winter old fish from Christiansand, where the 
material was largest and the most reliable, we find that in 1908 they were 
56°2cm.in length and weighed 16°8 hectos, whereas in 1909 they were 


* With a fish which grows so rapidly as the salmon considerations of this sort are 
bound to affect the average. 


42 THE AGE AND GROWTH OF SALMON AND TROUT. 


much shorter and nevertheless were heavier. This is also the case if we 
examine the two winters old fish from the same locality. The yearly varia- 
tion in the proportion of weight to length in the same district can therefore 
be so large that one year may show just the contrary to another year. It 
would therefore involve us in many difficulties if we attempted to establish 
this proportion as a means of studying the question of race. 

There is yet another point, on which the average figures which we have 
collected in our table on page 40 give us clear elucidation. That is the 
proportion between the growth of maiden fish and that of fish whose scales 
have spawning marks, and which, therefore, have returned to fresh water 
on a@ previous occasion to spawn. 

As an example let us take the figures shown in the table for Christiansand 
in 1909. 


Average Length and Weight of Salmon which after Migration 
had Completed 


2 Winters. 8 Winters. 


Length in cm. | Weight in hectogr. | Length in cm. | Weight in hectogr. 


Fish without spawning mark| 78 41 91°83 88°4 


Fish with spawning mark .| 61°2 22°9 T5'1 42°7 


This table shows us quite clearly what a serious check the spawning 
journey and the actual spawning itself put on the growth and the weight of 
the fish. Whereas two winters old fish which have never spawned are 
78 cm. long and weigh 41 hectos, fish of a corresponding age, but which 
have spawned in the previous winter, are not more than 61°2 cm. long and 
weigh only 22°9 hectos; and whereas a three winters old maiden fish is 
91°83 cm. in length and weighs 88°4 hectos, a salmon of the same age, but 
which has previously spawned, whether in its second or third winter, is 
only 75°1 cm. in length and weighs on the average not more than 
42-7 hectos; that is to say, little more than a maiden fish which has been 
a year lessin the sea subsequent to migration. 

This clearly shows how great is the retrograde influence on the growth 
of the salmon of the act of spawning and of the difficulties and privations 
connected therewith. 

It is easy to see that this must be the case, for while one salmon 
remains in the river for many months, fasting and becoming emaciated, on 
the other hand the unripe fish of corresponding age remains in the sea, 


ON SALMON. : 43 


feeding and growing, and until it greatly surpasses in weight its contem- 
porary in the river. 

And if such a fish spawns and survives to regain salt water, a long time 
must elapse before it can recover merely the weight it has lost in the river 
and until it can begin to increase in size over its original weight, when it 
first left the sea for the act of spawning. Consequently it can never reach 
the normal weight for maiden fish of corresponding age. 

The whole of the material in my tables shows the same conditions, and 
I have merely selected the above as a characteristic example. 


‘(d.) The Fielative Occurrence of the Different Age-Classes in Different 
Localities. ; 


It has long been known that the salmon of the north and those of 


the south—for example, from the neighbourhood of Trondhjem or of 


Christiansand—are different in size. In the north they are considerably 
larger than in the south. | 

Herr Landmark has proved this by a large number of measurements, 
and in my investigations, with the help of several firms, I have collected 
a quantity of material which clearly proves the correctness of this theory. 

In a number of the icehouses where fish are bought there exist statistics © 
spread over many years giving the total catch and weight of grilse (fish 
under 3 kilos) and of salmon (fish of 3 kilos and over) which have passed 
through each fish-house. 

I have collected the statistics which I have obtained from the Christian- 
sand and Trondhjem districts, together with those of the fish caught with 
rod in the State-owned rivers in Finmarken. (See table below.) 

The table shows us two facts. In the first place the quantity of grilse 
in proportion to salmon decreases as we proceed northwards. Secondly, 
the average size of both grilse and salmon increases the farther north we 
go. This is especially the case with salmon. 


Grilse. Salmon. 


eae Years. Number | Average| Number | Average 
of fish Weight of fish Weight 
Weighed. | in kilo, | weighed. | in kilo. - 


Randgsund and Flekkerg rs ay 


Association, Christiansand . 1895—1909 | 38,012 1°9 | 38,006 49 
Moltuen Icehouse, near Trondhjem . .| 1898—1908 3,387 21 6,173 6:9 
Utvorden Icehouse, Namsenfjord -| 1898—1908 5,010 2°3 | 13,027 6'8 
Rod fishing on salmon rivers, 

Finmarken . 3 ; - | 1898—1909 152 — 495 9-2 


44 THE AGE AND GROWTH OF SALMON AND TROUT. 
The number of years and the quantity of fish which are included in 


these statistics are so large, both for the Christiansand and for the Trondhjem 
districts, that there is no room left for doubt that the difference which we 


LG Laksens gjennemsnitsvege t aarene WI8-1908. 
A commana frame ee ved Kristiansand. 
| —~- Moltuen ( Trondhjemsfyord). 
bs } --—-—-— —»— Utvorden (Namsenfjord :). 
\ 
if) 
ut 
Bout 
La 
\\ 
\\ Pal 
\ 6 
ZS + FL Le. 
i} "Ae \, 
\\ ya & ra r. 
tt 7A sens AS SR eT 
Zo ne zs L ay \ il X 
\\ a PE st\ es 
a3 aE 
ca \ Z 
fi \ 
LL “\ 4 
/ ES 
6.0 A TCT 
as 
ALT 
35 
3.0 ave Zz — a 7 x re ns 
~ Pci v 7 © 
4.5 " 
098 1899 1900 1004 71902 1903 700% 1905 1006 1907 1008 


the years 1898 to 1908. 


Fic. 28.—Annual Average Weights of Salmon (fish of three kilos and upwards) at 
Christiansand, Moltuen (Trondhjems fjord), and Utvorden (Namsen) during 


find between these two districts must be regarded as a permanent charac- 


teristic of the difference which is generally found between the catches in 
these different localities. 


A yearly variation is noticeable both in the proportion of salmon to 
grilse as well as in the average weight. 


ON SALMON. | . 46 


As regards the annual fluctuations in the average weight we find most 
remarkable coincidences between the various districts, as will be seen from 
the curves in the accompanying chart. (See Fig. 28.) 

In the first place we notice that the yearly variations in the average 
weight of the fish are so considerable that they must be an important factor 
in the annual yield of the fisheries. Secondly, we must note that these 
variations follow one another with considerable regularity. It is obvious 
that there must be some common cause responsible for the regularity with 
which in the various years the average weight rises or falls simultaneously 
in districts which areso remote from one another, 

In Finmarken the statistics are less convincing. It has been difficult 
for me to obtain even this small amount of material from the Lakselv, 
consisting of the fish which the lessee had caught in the State waters in 
the years 1898 to 1909. 

We have statements alsofrom a number.of icehouses, both in Nordland 
and Finmarken, but unfortunately they are of no use for a direct com- 
parison, as the division between grilse and salmon in this district is arranged 
on a different system from that prevailing in other parts of Norway. As 
mentioned before, throughout the rest of the country the division between 
grilse and salmon is reckoned as 8 kilos, whereas in the northern districts — 
it varies from 3°5 and 4 kilos in Nordland and Tromse up to 6 kilos in 
Finmarken. This renders a direct comparison impossible, and one can 
only form approximate estimates. 

Nevertheless, the following statistics obtained from the ice-houses in 
Norskholmen, Tana, and Bugenes, in Sydvaranger, for the years 1903 to 
1908 are characteristic of Hast Finmarken. 


Locality. “under @kilos. | of and over 6 kilos. 
Norskholmen Tana . 1633 1670 
Bugenes-Sydvaranger 3063 3023 


As will be seen, these figures leave one in no doubt that actual grilse 
(1.¢., fish under 3 kilos) are far less numerous than salmon. 

In the districts between Trondhjem and West Finmarken the propor- 
tion varies considerably in different localities, and there are places where we 
find that fish under 8 kilos are the most numerous, as, for instance, in the 
small fjords around the Vestfjord, and possibly also on the outer side of 
Sere. 


So far as the southern coast is concerned, I should not like the 


46 THE AGE AND GROWTH OF SALMON AND TROUT. 


statistics previously given to be taken as representing anything more than 
the localities to which, they refer. It is well known that the catches in 
certain places—for example, in Jaederen—sometimes consist almost entirely — 
of grilse. 

The tables given above must therefore only be regarded as typical 
examples of the fact, which long experience has shown to be correct, that 
salmon in the north are larger than those in the south, 

What, therefore, is the reason of this difference ? 

If one fish is larger than another we are naturally inclined to think 
that it is because it is older. 

Let us therefore again examine the statistics which have been compiled 
from the material which we have examined from Christiansand, Trondhjem, 
and Kast Finmarken. 

For the purpose of comparison let us arrange the various age-groups 
according to their percentage. (See the accompanying table.) 


Percentage of Fish which after Migration had Lived 


Year. District. 
1 winter. 2 winters, 8 winters. | 4 winters. | 5 winters. | 6 winters, 
1908 |Christiansand | 368 % 56°7 % 75% 0-4 % _— fa 
—. |Tréndelagen 93% 634% 269 % 04% — rae 
— |@st-Finmarken| 17:9 % 23°7 % 551% | 34% — =e 
1909 |Christiansand | 382% | 552% 62% | 03% pat 0-1 
— |Trgndelagen 24 % 40°7 % 315 % 27% 1:1 % fi 
— |@st-Finmarken — 92% 82:4 % 74% 18% es 


An inspection of these tables clearly shows that the salmon in the 
Trondhjem district are distinctly older than in Christiansand, and that a 
similar difference is noticeable between Trondhjem and East Finmarken. 

It must, however, be noted that the material from East Finmarken is, 
unfortunately, not large, and there is also the disadvantage that it does not 
represent the whole season. The examples of 1908 were caught in the 
middle of July, and therefore at a time when the actual season for large 
salmon is over, and which is generally characterised by the predominance 
of small salmon and grilse. This table, therefore, probably gives too high 
a relative value to the younger fish. In 1909 the buying of fish at the 
Bugenes Ice-house in Sydvaranger was discontinued at the beginning of 
July, and consequently put an end to my collection. For the same reason 
as before, the material collected in this season overrates to some extent the 


larger and older fish. 
Neither of these two examples above can therefore be regarded as 


ON SALMON. | 47 


absolutely representative of the general stock of fish in each year, but 
taken together they leave no doubt that the salmon in Hast Finmarken 
are distinctly older than those in the neighbourhood of Trondhjem. 

Our investigations therefore seem to indicate clearly that the salmon 
caught in the north are, on the average, considerably older than those caught 
farther south, and that thisis one of the chief reasons of the difference in size 
which has so long been recognised. 

Let us now inquire whether the average weight of the various year 
classes can also be regarded as a contributing factor to the difference in the 
size of the fish in the various districts. For this purpose we may compare 
the average weights previously given in the table on page 40. 


Average Weight in hectogrammes of Maiden Salmon which after Migration 
had lived 
Locality. 1 winter. 2 winters. 8 winters. 

1908. 1909. 1908. ~ 1909. 1908. 1909. 
Christiansand . : ; 16°8 17°1 39°7 41 111°6 88°4 
Moltuen . , ; 3 17:9 19°5 50°9 49-1 105°9 100°8 

Orkla , ; 18°1 —_— 59 — 105 — 
Ost- Finmarken ; -| 20% — 49°1 44:2 96:2 79°9 


As we see from this table, there is some difference in the average 
weight of salmon of the corresponding year-classes in the different localities. 
Possibly this is due to an actual difference in conditions, or it may be that 
it is merely the result of chance. With so rapidly a growing fish as the 
salmon, the date of capture must have an important influence on the 
average weight; and for this reason, when instituting a comparison between 
the different localities, we must not place implicit confidence in the results 
obtained. 

As we see, the difference is not so great, nor is it sufficiently regular to 
explain fully this variation which we have previously shown to exist in the 
various districts (cf. page 48) even though it may possibly be a contributing 
cause. 

In the same way we notice in the tables an annual variation in the 
average of salmon belonging to the same year-classes. This is, however, 
not important enough to explain the large annual variations which we 
found in the average weights of fish over 8 kilos. (Seepage 44.) 

It is most probable that annual variations in age-composition in this 
respect play avery important rdle. That such variations do exist is appa- 
rent if we examine the tables in which the age groups are arranged according 


48 THE AGE AND GROWTH OF SALMON AND TROUT. 


to the percentage (see page 46). Here we see that the percentages of the 
different age-classes vary from year to year, but we can only arrive at a 
sound conclusion as to the extent of this variation by continuous investi- 
gations spread over several years. 

What is the meaning of the greater age » tial we find in comparing 
our examples from the north with the south? Does it indicate that salmon 
have atendency to migrate northwards as they get older, or does it indicate 
that northern salmon take longer to become mature, and that it is only 
when they are older that they approach the coast and proceed up the 
rivers ? 

It is impossible to reply with any degree of certainty, but the circum- 
stances are exceedingly striking and deserve further study. 

I will only merely mention the fact that the materials I have collected 
seem to indicate that both the above-mentioned factors may contribute 
their share. 

As will be remembered in our discussions on the age of the smolts 
before migration, and as to the occurrence of the spawning mark in reference 
to age, we found the following facts. The smolts remain longer in the 
rivers in the north than in the south, and if we investigate the age of fish, 
when the spawning mark was first formed upon their scales, we find that 
they must on the whole have been older, which moreover directly follows 
from the fact that the stock of fish generally is older. After spawning, 
the salmon, as far as we can discover (see page 39), also remains longer in 
the sea in the north than in the south, before it returns to spawn for the 
second time. It would seem as if all the functions of the fish are more 
retarded the further northwards we go. Ordinary physiological considera- 
tions would lead one also to expect this, and there can be little doubt that 
this condition must to some extent make itself felt. 

In order to elucidate the question of the wanderings of the salmon I 
have endeavoured to ascertain whether the markings carried out by Herr 
Landmark afford any indications. These markings were almost all made on 
spawning salmon, that is to say, fish whose chances of survival, in the light 
of what. we have discovered, could only be regarded as small. That is 
presumably the reason why of the many thousands of salmon which 
were marked so few fish have been subsequently recaptured.* 


* During the years 1893 to 1895, 6708 fish were marked in the rivers, principally 
spent fish and kelts, and only 221 fish in all have been recaptured. Of these 221 salmon, 
43 were caught again before they had migrated to the sea, 54 were recaptured in the sea, 
and 112 on their return to fresh water, and in the majority of cases in the same 
rivers where they were originally marked. During the same period 140 clean fish were 
marked which were caught among the islands along the coast. Of these 23 were recap- 
tured, and in all cases in the same season in which the marking took place. (Landmark, 
‘* Merkning af Laks,” Norsk Fiskeritidende, 1905, p. 487.) 


ON SALMON. 49 


Laks merkel 0g gyenfangel 
t s7oen, andetsleds end 


t den elvemunding 
eller fjord, hvor elven 


munmader. 


Fic. 29.—Map of Southern Norway, showing the Migrations of Salmon which were 
marked as Kelts in various rivers (Drammen, Sire-Aa, Figgen and Sand), and 
which were recaptured in the sea elsewhere than in the mouth or fjord leading 
to the river where the fish were originally marked. 


8.T. 4 


50 THE AGE AND GROWTH OF SALMON AND TROUT. 


As is well known, Herr Landmark’s marking experiments indicated 
that many fish have a great tendency to return to the river where they were 
marked, but all the same a fair number may go to other places. On the 
map of Southern Norway (Fig. 29) I have indicated the tracks followed by 
those salmon which have been recaptured in the sea elsewhere than in the 
river mouths or in the fjords leading to those rivers in which they were 
marked. These are, therefore, the only fish which can give us any indica- 
tion of where those fish go which do not return to the river in which they 
were marked (see Fig. 29). 

We see at once from this map that most of the tracks have a noticeable 
tendency towards the north. I have drawn a line from the place of marking 
to the place of recapture, and naturally we know nothing further of the 
wanderings of the fish between these two places. 

Naturally, we cannot draw any sure and final conclusions from this, 
but taken in connection with what we saw of the age distribution of salmon 
along the coast, these wanderings are both interesting and instructive. 

That they do take place is an established fact. That they must play 
a certain part in the remarkable age distribution of the fish along the coast 
cannot be denied, even if for the present we are not in a position to say 
precisely what weight we should attach to them. 

In this connection it will also be interesting to compare the distribution 
of the salmon fisheries along our coasts. For this purpose I have divided 
up the coast into three divisions :— 

1. From the Swedish frontier to Jaederen (to the Stavanger Amt). 

2. From Jaederen to Stat (to the Romsdal Amt). 

8. From Stat to the Russian frontier. 

For each of these three districts I have put down from the Fishery 
Inspector’s statistics the weight of salmon caught in the years 1880 to 1906 
in the whole of the fisheries both in the rivers and the sea. In the accom- 
panying table I have given the results in round figures, together with 
the proportion between the separate yield from river and sea. 

It is possible that the figures obtained are not strictly comparable, 
owing to the fact that it is only in recent years that the sea fishing has been 
developed in the northern districts, whereas river fishing has been going 
on for along time. In the same way difficulties arise as to the comparison 
of the statistics from other parts of Norway.* - 

However, if we take the figures as they are our table gives us the 


following. 
We see that in the south the river fisheries are of much greater 


* For example, we have disregarded the fact that the leasing of rivers for sport 
fishing, i.e., as opposed to netting or trapping, is much more extensive in the north and 
west than in the south. 


ON SALMON. 51 


importance compared with those in the west and north. If we regard 
the relative importance of the yield of the river fishing in proportion to the 
whole catch as an indication of the intensity of spawning, it would seem that 
relatively there is far more spawning in the south, but we also find that 
spawning results in a relatively far larger total yield as we proceed 
northwards. 


1880—1906. 
Yield of River Fishing | Yield of Sea Fishing |Proportion between 
in kilos. in kilos. River and Sea. 
Swedish Frontier to Jaederen . . 2,212,000 3,767,000 1—1'7 
Jaederen to Stat . f . P 1,161,000 5,552,000 1—4'8 
Stat to Russian frontier . 3 ; 2,288,000 8,920,000 1—3°9 


It is impossible without further information to say whether it is a fact 
that some of the fish which are hatched in the south go northwards when 
older, or whether it is that the southern fish return to spawn when they are 
younger and smaller, whereas the northern fish only return to spawn when 
they are older and heavier (and in this way each individual smolt would 
eventually give a larger result in weight). For the present this must remain 
an open question. It is most likely, after what we have seen, that both 
causes are operative, but, in any case, this remarkable geographic 
distribution of yield in our salmon fisheries has had new light throw 
upon it, and that, too, from a source which has not hitherto been 
available. 

(e.) Distribution of the Year-Classes. 


As I have stated previously, and as will be seen on examination of the 
tables in the Appendix, the smolts are not all of the same age, nor have 
they all spent an equal time in the sea when they return for the first time 
to spawn. 

Some return sooner, others later, quite independently of the age at 
migration. 

This circumstance is a matter of great importance to the general stock 
of salmon, as we shall see later. 

In the following table I have arranged all the fish I have investigated 
from Christiansand, 'T'rondhjem and Hast Finmarken in 1908 and 1909, - 
according to district and year of birth. 

When we examine the table carefully it is evident that the fish which 
we have to deal with in our fisheries in any one season, and of which the 
majority are on their way to the rivers to spawn for the first time* are born 

* Fish with spawning marks are also included, but as was seen before, they are only 


a very small proportion—2 to 10 % of the total catch. 
2 


52 THE AGE AND GROWTH OF SALMON AND TROUT. 


Of which the following number were born in 
Locality. Year. | eer 

1906. 1905. 1904. 1908. 1902. 1901. 1900. 

Christi 1908 | 667 | — | 118 | 196 | 290 58 ee a 
tiansand . | 1999 | 1,612 98 622 | 678 | 186 25 1 2 

1908 | 498 | — 11 66 | 268 | 149 | 19 | — 

Trendelagen .| 1999 | 184 |. 6 | 32 | oe | 67 | 2 | 2 | — 
: 1908 87 | — ik, 11 22 39 | 12 3 
Ost-Finmarken | i999 | 984 | — 1 17 | 121 | 112 | 98 | 5 


in quite different years, and originate from a series of different spawnings 
the effects of which have been spread over six or seven successive years. 

There has been a very widely-spread belief that the results of a successful 
smolt year or spawning year after the lapse of a definite interval of time— 
as to the length of which there were many different theories—would again 
show themselves in the form of a year of plentiful salmon or large catches. 
As can now be seen, the results of any one spawning—good or bad—are 
spread over the catches of six or seven years, and in such a manner that it 
seems improbable that we shall be able by means of statistics to show any 
remarkable difference in the effects of the different spawnings. In any case, 
in attempts to solve this problem we should have to reckon with so many 
doubtful points that the results would be most untrustworthy. A closer 
examination of the table shows this most clearly. Amongst other things it 
is at once evident that similar conditions do not prevail in the south and in 
the north, owing to the fact that in various years different year-classes con- 
stitute the bulk of the catch in different localities. 

What, however, must at once strike one, is the remarkable manner in 
which this distribution of the product of each year’s spawning must operate 
for the preservation of the species. When the results of any one spawning 
are spread over the catches of so many years, and when they are scattered 
so heterogeneously during different years throughout the various districts, it 
must in the highest degree tend to work as a sort of insurance for the species, 
and as a division of the risk attached to each individual fish. 


CHAPTER III. 


ON TROUT. 


Anyone who knows the manifold variety of forms which trout may 
assume in Norway, and the immense number of streams and lakes with 
totally distinct conditions of existence in which they are found, will be aware 
of the impossibility of attempting a geograpHical classification of the age 
and growth of trout on similar lines to those we have followed in the case 
of salmon. 

As a preliminary step, therefore, and merely as an introduction to the 
study of trout-forms, I decided to collect a number of examples for an 
initiatory comparison of characteristic forms to further a comparison 
of the stock in various characteristic localities. 

In the first place I have endeavoured to obtain material which would ~ 
enable one to make a comparison between sea-trout and fresh-water trout in 
their many “forms,” such as burn-trout and trout from lakes where the fish 
“are not big,” trout from “ good” lakes where the fish are large, and finally 
the largest of all our trout forms the Mjesen or ‘‘ Hunner” trout. In 
the second place I have made an attempt to investigate the stock in waters 
to which both sea-trout and inland trout have access, and also at places 
where the fresh-water form only is found, and where access 'from the 
sea is impossible. 

As I shall point out later, all the differences which lend themselves to 
demonstration may be reduced to variations in age and growth, and these 
differences vary very considerably in separate localities, while there may 


be intermediate stages of every sort and kind. 


The old division into burn-trout, mountain trout, lake trout, etc., 
appears, therefore, of little use as a basis for discussion, nor would a classi- 
fication according to growth and manner of growth be feasible without 
elaborate proof; I shall therefore confine myself to showing by means of 
some characteristic instances the results of my investigations, and afterwards, 
in a later chapter, deal with the growth and manner of growth of our sal- 
monidae, and consider which types it might be possible to classify separately. 

I have put down in tabular form in the Appendix only as much of 
my material as was necessary for evidence, and which was too voluminous 
to be included in the text. 


54 THE AGE AND GROWTH OF SALMON AND TROUT. 


A. Instances of Sea Trout and of the Rivers to which they 
have Access. 


Sea trout, like salmon, spend the early years of their life in rivers 
or fresh-water lakes. The duration of their stay there, before migrating 
to the sea, varies just as it does for salmon, and the young smolts are 
not all of equal age. 

This circumstance we can investigate in two ways. 

We can investigate the age of the young fish that live in the rivers, 
and so get in certain cases an idea as to the duration of their stay there, but 
we are faced here with a complication. For whereas no salmon attain any 
considerable size before repairing to the sea, and as the females never, to 
my knowledge, develop their ova before they migrate to salt water, we find 
in many streams quite different conditions in the case of trout. 

_ In many streams where sea trout are found, trout may be met with which 
attain considerable size and age and even maturity without having migrated 
to the sea, and it is often very difficult therefore to say whether we are 
dealing with the young of the sea trout, or whether the young fish we find 
do not also include the offspring of fish that have never repaired to the sea ; 
since by their outward appearance it is impossible to distinguish them. 

The scales of the sea trout, however, show growth conditions resembling 
those of the salmon. In the river they develop slowly, in the sea extremely 
rapidly. We can accordingly, in most cases, detect the boundary line on 
the scale, which denotes the transition from poor to good growth, and 
we can note the number of winters which the fish has completed prior to 
migration. 

As I did in the case of salmon, so also with trout I have endeavoured 
to obtain information by studying the scales with regard to the length of 
time which the fish have spent in the river previous to migration. 

In Table XVIL., I have put down the results of an analysis of 192 sea 
trout, taken from unsorted catches with the drag net that were sold to 
a fish dealer in Trondhjem on June 26 and 27, 1909. 

This analysis has been worked out and arranged in the same way as 
was done on page 28 in the case of salmon. 

If we take the results of this analysis, as regards age of migration, we 
get the following :— 


Of these the Following had Completed previous to Migration 


Number of fish 
Examined. 


2 winters. 8 winters. 4 winters. 5 winters. 6 winters. 


192 25 78 67 21 1 


ON TROUT. | 55 


Here we meet once more with an age distribution similar to what we 
found to be the case with salmon smolts from the same district, that is to 
say, the majority are three to four years old when they repair to the sea. 

The tables in my previous publication ‘‘ @rret og Unglaks”’ gave some . 
interesting information as to the size of these sea trout smolts, as I measured 
a number of them when they were actually migrating from the rivers of 
the Trondhjem district in May and June. Their length varied between 
10 cm. and 20 cm. . 

For purposes of comparison I have also made out the following 
calculation of the sizes of the young fish at the time of migration from 
measurements of the scales of the sea trout referred to in Table XVII. 
I selected in this connection the 118 fish which had lived one winter 
subsequent to migration. 


Caleulated Length Number of oe Of these the Following had Lived previous to Migration 
: pareve 2 winters. 3 winters. 4 winters. 5 winters. 
10 1 1 — — — 
11 5 2 8 — — 
12 7 4 8 — — 
13 13 2 9 2 — 
14 19 2 7 10 _ 
15 18 1 7 10 —_— 
16 13 — 8 4. 1 
17 12 1 8 7 1 
18 11 1 5 4 1 
19 5 — 2 2 1 
20 7 — a 4 3 
21 2 —= — 2 — 
22 1 — —~ 1 —_ 
23 — -— — — — 
24 —_ —- —- — 
25 2 — — 1 1 
26 2 a — 1 1 
Total : 118 14 AT 48 9 
Average lengthincem. . 13°1 14°8 16°8 20°1 


From the above we see that the calculated lengths of the sea trout 
smolts range from 10 cm. to a little over 20 cm., being about the same extent 
of variation which I previously found in the actual measurements of smolts 
caught at the mouths of the rivers of the Trondhjem district, but we 


56 THE AGE AND GROWTH OF SALMON AND TROUT. 


can now classify the sizes according to the different age-classes which 
migrate. Hach of these classes, as will be seen, has its own limits of 
variation, the average size invariably increasing with age. 

It is also worth noting that some of the fish which migrated at a later 
period of life appear to have been of considerable size when they left the 
river for the sea. 

If we now turn our attention once more to Table XVII., we find, as was 
the case in the corresponding tables for salmon, valuable information 
regarding the fish after its first journey to the sea. 

It must be remembered that the table only refers to saleable fish. The 
limit below which fish are unsaleable is about 20 cm., so that the majority 
of the young fish which migrated in May and June for the first time 
in their lives are of course excluded. We merely get a few of the largest of 
them in the first group, i.e., those which have not completed a winter after 
migration, and which consists of those sea trout that have just quitted 
the river. It follows that neither number nor average size in the case 
of these fish is of any quantative value for determining the total stock. 
On the other hand, the older groups (one winter, two winters, three winters, 
etc., after migration) are fully represented in the catches, and both numbers 
and sizes have therefore a definite value for determining the composition 
of the stock and the growth of the fish. 

Summarising the information obtained from the table we get the 
following :— 


For the 174 Fish that had Lived after Migration 


1 winter. 2 winters, 8 winters, 4 winters. 
Number of fish. ; ’ ‘ 118 45 5 6 
Average lengthinem. .. : 30°1 38°8 47°7 55°7 
Average weight in hectograms 2°7 56 11 14°8 


In the matter of the numbers of individuals in each age-class there is 
here much that reminds one of what we found in the case of salmon, The 
sea trout caught by the nets consist mainly of fish that have lived from one 
to four winters subsequent to migration, fish of higher ages occurring only 
exceptionally. At any rate, in my search for large sea trout I have rarely 
met with individuals that had attained greater age. 

What value must be ascribed to the relative distribution of the whole 
stock among these four age-classes is another question. It is quite probable 
that other samples may show higher figures for the older classes, Still I 
feel quite convinced that the older classes are generally characterised by a 
diminishing number of individuals. The bulk of the sea trout brought to 


—- 


ON TROUT. 57 


market in Norway are always about 20cm. to 40 cm, in length, as can be 
verified by examining all the measurements made in this country. 

In order to form an idea as to how the general stock in the Trondhjem- 
fjord compares with the examples taken from the catches of the fishermen 
referred toin Table XVII., I have made the following summary of my catches 
in that district during the years 1898—1900, which was published in 
tabular form in Orret og Unglaks. 

The summary indicates that the larger and older sea trout occur in 
relatively small numbers, and that the figures given in Table XVIL., rather 
over-estimate than under-estimate the frequency of the larger and older fish. 


Number of Fish in Number of Fish 
Length in em. Dahl's Catches investigated in 
1898—1900. Table XVII. 

10—20 563 — 
20—30 - 659 81 
30—40 118 - 85 
40—50 39 20 
50—60 8 5 
60—70 — 1 
Total 1387 192 


Interesting information with regard to growth is also given in our 
summary on page 56, and more especially as regards the figures for 
length and weight of fish which had completed one and two winters after 
migration. These figures are based on so large a number of observations 
that they may be accepted without reserve. The values for fish that had 
lived three and four winters after migration may be less convincing, but 
they give a tolerably sound indication of the rate of growth. 

As regards the growth of sea trout in other parts of the country, I 
have as yet but little information, and it is quite possible that the growth 
may differ to some extent in different localities. 

The only placefrom which Ihave any material which admits of comparison 
is Utskarpen in Ranenfjord (see Table XIX.) and comparing the figures we get: 


Average Length in cm. of Fish which after Migration had Lived 


1 winter. 2 winters. 8 winters. 4 winters. 


Trondhjem Fjord, 
June 26th—29th 30°1 38°8 47 ‘2 557 
Utskarpen, Ranenfjord - 
September 1st—10th 33°3 41°4 — = 


58 THE AGE AND GROWTH OF SALMON AND TROUT. 


Remembering the fact that these samples from Utskarpen have been 
taken two months later in the season than the samples from the Trondhjem- 
fjord, and also in a different year, we are entitled to say that the average 
lengths are in fairly close agreement. Consequently if the growth is so 
similar in districts so remote from one another, we are justified in assuming 
that these values are fairly characteristic, at any rate for the northern parts of 
the country. This assumption, moreover, is confirmed by various small 
samples which I have occasionally had the opportunity of examining. 

How matters stand in the south I have not yet sufficient material to 
say, though a few samples from the Os river near Bergen and from the 
Sendeled river at Riser show no essential difference from what I have 
described in the case of the northern streams. 

With regard to maturity in sea trout, both prior to and subsequent to 
migration, our sample from the Trondhjem-fjord unfortunately does not tell us 
anything, since we were unable to make the necessary examination of the fish. 

I have, however, obtained valuable information from a large sample 
obtained from Utskarpen in Ranen. 

In Tables XVIII. and XIX., Ihave made an analysis of the samples that 
were taken between 1st and 10th September, 1907, partly in the Dalos 
river at Utskarpen and partly in the sea at the mouth of the stream. 

Table XVIII. includes all the fish which were caught in the Dalos river, 
and which, both by their appearance and from the structure of their scales, 
may be said never to have quitted it. 

The table shows us that it is only exceptionally that the river contains 
fish which are more than six winters old, and which have not been to 
the sea. Consequently we are dealing here practically solely with those 
age-classes which characterise the sea trout smolts. Their size, too, as 
we notice, varies between 10 cm. and 25 cm., exactly what was found to 
be the case with the migrating sea trout in the Trondhjem-fjord. 

By means of the table we can make out the following summary of 
sex and maturity in relation to age. 


Number of Fish September 1—10, 1907. 


Age in winters. ri g 


Mature. Immature. Mature. Immature, 


© & Or C bo 
Ll lL Hot 


|| | aa 


ON TROUT. 59 


Ié will be noticed that there are no mature fish among any of the 
individuals which are only two or three winters old, and that males and 
females occur in about equal numbers. It is only in the older groups, 
from four winters upwards, that we meet with maturity, and these mature — 
fish are, without exception, males. The older females have migrated. 
Thus we meet here with conditions quite analogaus to those we found in the 
case of salmon parr so far as maturity and sex are concerned. The table 
shows us also that this river does not contain any other trout than sea 
trout, since no stock could last which depended solely on spawning males. 
If fresh water trout or stationary trout existed side by side with the sea 
trout we should be sure of the fact by a relatively plentiful occurrence of 
mature females. 

The fish in the Dalos river, therefore, which have not been to the sea, 
are merely the young progeny which have not yet migrated, and of which 
only the oldest males are mature, and the supplement of the stock is to be 
found by examining the fish, which have evidently been in the sea, and 
which are given in Table XIX. 

By means of this table we can draw up the following statement of sex 
and sexual characteristics, in relation to the number of winters which the 
fish had completed after migration. : 


Number of Fish September 1—10, 1907. 
‘Migration. 3 2 
Mature. Immature. Mature. Immature. 
0 6 11 — 20 
1 10 7 3 9 
2 4 2 8 _— 
3 — — 1 — 
4 1 oe —— — 


This shows us in the first place that the number of males and females 
in the corresponding stages of existence is fairly equally balanced. Here, 
too, the males are the first to begin spawning, as some of them spawn after 
merely one summer in the sea. After a stay of one winter and more in 
the sea the proportion of both males and females which spawn is 
increasingly augmented, though in each age-class there are still some 
that do not participate. It is not until we reach the oldest stages that we 
find that all the fish enter the river to spawn. 

In Table XX., I have endeavoured to illustrate this state of affairs 


60 THE AGE AND GROWTH OF SALMON AND TROUT. 


still further by comparing the aggregate age of trout that have 
never been in the sea and of sea trout. The comparison works out 
as follows :— 


River Fish. Sea Fish. 
si OH ty 
3 z 3 4 
2 (12 9 —_ 2 
3 9 16 1 4 
4 4 1 17 11 
5 6 _- 16 12 
6 3 _- 6 9 
7 _ — — 4 
9 1 _- — — 


Two things are clear from this. In the river the number of individuals 
decreases as we approach the maximum age of migration. In the sea it 
increases from the minimum age of migration and decreases as we approach 
the limit of the fish’s life. 

The absence of females in the later year-classes in the river is 
evidently due to the fact that they have migrated. 

Consequently the stock of fish that have never been in salt water 
and the stock of fish that have migrated are supplementary to each 
other. 

Similar conditions are met with in many of the streams to which sea 
trout have access. If we examine the stock of fish that has never been 
in the sea, we find that in many places males and females often occur in 
equal proportion in the youngest year-classes, whereas the older year-classes 
consist mainly, and at the end exclusively, of males. This must be regarded 
as a sure sign that the stream in question chiefly contains fish that will 
become sea trout. 

In many places, however, this is not so obvious, and in some streams to 
which sea trout have access, we may even find that the proportion between 
males and females is only slightly affected by age, and that spawning 
females occur which have never migrated. 

Instances of such streams are Aagvand in Redgherred, Nordland 
(see Table XXI.), Kvernvand in Naerg, Namdalen (see Table XXII), Meln- 
bugtselv in Agdenes (see Table XXIII.), and the Os river near Bergen (see 
Tables XXIV.—XXVL). 

From these tables we are able to obtain the following comparison :— 


ON TROUT. | 61 


4 Number of Fish which have Lived 
“A 
” 
“ ‘ F ‘ . ‘ 4 
Locality. ey 4 1 winter. 2 winters. | 8 winters. | 4 winters. 5 winters. | 6 winters. | 7 winters 
§ 
| 
Zi Ft SO PSS ob Son So fFoPrweVvs Ser gre 
Aagvand . . 44 -- —- 1 6 13* 9* 10* 2* — —_i—- —_}— 
Kvernvand. % 95 —_ — 13* 14 12* 34* 4* 15* —_ 8* _ — _—-|— 
Molnbugtselv . 62 6 7 18* | 21* Q* 1 4* 1* | Q* —h— | —) — joe 
Osvasdraget 1 . 55 _ _ 1 4 15* 11* 9* 3 1 2 a _ 1 
Do. 2...) 155 4 - 387 86 32 13* | 16* 8* | 5* 4* — | — fp — | — 
3 yoo 
Do. 8 .| 182 5 29 21 28 21 14* | 12* | 4* 4* —)/—{|[—]— 


* Denotes that mature fish occurred in that particular year-class. 


Here we see in the first place that the proportion between males and 
females varies greatly in different localities. 

In Aagvand and Melnbugtselv we find the typical decrease in the age 
of females mentioned in the case of Utskarpen. 

In the Os river the samples have been taken from a succession of 
catches from the mouth of the river and up stream, and numbered 
respectively 1, 2, and 3. Here, again, nearest the mouth, we find the 
typical absence of older females, whereas the higher up the river we go 
the more numerous do they appear to be. 

The proportion between the sexes is reversed, however, in Kvernvand. 
Here there are peculiar conditions owing to the out-flow being a very 
small burn, which is dry for a great part of the year, and the fish conse- 
quently are only able to ascend and descend when there is a spate, and I 
am compelled to state in this instance that I can only accept with considerable 
reserve the proportional number of individuals of the two sexes in the sample, 
as the writing of my amateur assistant at the examination has proved liable 
to misinterpretation. 

The next point to notice, from the figures marked with *, is that 
mature individuals may occur as early as the third, or sometimes even 
the second year, and that maturity is not confined to males, mature females 
also occurring.* 

A third point is that the maximum age for fish in these streams only 
rarely exceeds the maximum age at which sea trout migrate, and the 
numbers of individuals in the year-classes decrease, too, at a more or less 
rapid rate, as we approach this maximum age. There is thus nothing in 
this connection to prevent us assuming that this decrease is connected with 
migration. That it is due to migration, so far as a large part of the stock 


* In the case of the Os river my investigations took place so early in the year that 


it was only in a few instances we could decide with any degree of certainty whether 
maturity had commenced. 


62 THE AGE AND GROWTH OF SALMON AND TROUT. 


is concerned, is obvious enough; whether, however, the spawning females 
take part in this migration at a later period of their existence, or whether 
their lives terminate more quickly here than in land-locked lakes, where the 
fish attain considerably higher ages, is not easy to decide. 

This much, however, we can be positive about, that these streams to 
which sea trout have access, contain a stock, which mainly consists of young 
fish, and it is very probable that the whole of this stock of young fish 
contribute towards the recruiting of the stock of sea trout. This is, too, 
the most likely reason why we so seldom find older fish in these waters. 

With regard to rate of growth the conditions vary a good deal. I will 
set down here once more in tabular form the empirically found average 
sizes of trout in the waters referred to. They are taken from the tables 
already mentioned (Tables XXI.—XXYI.). 


Average Length in cm. of Fish that had Lived 


Place and Date. 
1 winter. 2 winters, 8 winters. 4 winters. 5 winters. 
Aagvand, Au: 12, 1908 ‘ —- 11:0 (7) 16 (22) | 20°8 (12 — 
Kvernvand, July 6, 1909. ¥ —- 19°1 (27 22°5 (46) | 25°6 (19 30°3 (3 
Molnsbugtselv, July 4, 1909 .}| 13-6 (18) | 19°3 (39) | 22°3 (3) | 25°8(5) | 30°5 (2 
Os River, May 19, 1909 . 9°5 (4) | 13°9(73) | 17-7 (45) | 20 (24) | 22°8(9 


The number of observations on which each average is based are added in brackets. 


B. Instances of Trout from Waters to which Sea Trout have no Access. 
1. Laxe Msosmn Trovr. 


We will first consider examples of the large trout which live in Lake 
Mjosen, and which in summer and autumn ascend the river Laagen to 
spawn. They are fished for in that stream under the name of ‘‘ Hunner 
Trout,” a name derived from the old fishery at the farm of Hunner. 

Herr Sogaard, of Lillehammer, has been kind enough to allow one of 
his employees to collect samples of scales from the trout which passed 
through his shop from the end of June to the beginning of September. 
The collection represents 171 fish, all taken in the Laagen above 
Lillehammer. ’ 

In Tables XXVII. and XXVIIz. I have put down the results of my 
analysis in the same way as I did in the tables for salmon previously 
described. Table XXVII. contains an analysis of age in relation to length, 
and Table XXVIIs. deals with age in relation to weight. 

The tables are arranged in such a way that the age of the fish, previous 
to and subsequent to migration is shown, but the statistics of size are given 
subsequent only to migration. 


ON TROUT. | 63: 


On examining the scales the reason for this arrangement will be 
evident. If we look at Fig. 28 (Plate VIII.), which represents the scale of 
one of these trout, nine winters old, we are at once struck by the sudden 
change in growth which occurred after the fourth winter. From the 
beginning of growth up to that period development must have been 
comparatively small, but in the following period of growth its development 
has been extremely rapid. Similar conditions were shown by the scales of 
all the fish in the sample, with perhaps one or two exceptions, as will be 
seen from the figures in Table XXVIIc. 

This table contains the calculated lengths of every fish on the completion 
of each winter-band (the calculations have been made in the manner 
previously described—by measuring the growth-zones of the scales). 

On looking through the series of figures for each individual it will be 
seen that in every case the fish had, after a shorter or longer period of 
adolescence with relatively poor growth, experienced a sudden change in 
development. 

I have not investigated the younger stages of Mjesen trout. Still, as 
the fish spawn in the Laagen, and the young trout undoubtedly live for a 
long time in this river before migrating to the lake, I have felt myself 
justified in considering this alteration in the rate of growth as an indication 
of the time at which—analogous to salmon and sea trout—they left the © 
river and repaired to the richer waters of the lake. It is, moreover, 
immaterial whether we call the boundary line between the two periods of 
growth, one of migration, or one of change of growth. The main point is 
that we can sufficiently clearly distinguish this division and determine the 
duration of the two periods. 

We shall now proceed to consider what the tables teach us. 

From Table XXVII. we obtain the following figures relating to the age 
at which migration or change of growth takes place :— 


Of these the following at the — of ne gre or Change of Growth had 


Number of Individuals mple 
Examined. 
3 winters. 4 winters. 5 winters. 6 winters. 


Here we find that migration or change of growth does not take place in 
every instance at the same age, which is precisely what we discovered in 
the case of salmon and sea trout. In some fish it begins early, in others 
later, and so, too, the table shows us that the majority appear on the 
whole to be older than salmon and sea trout at the time when this change 


64 THE AGE AND GROWTH OF SALMON AND TROUT. 


of growth takes place. A comparison of the corresponding tables for salmon 
and trout will make this clear (see pages 31 and 54), 

With regard to the size which the majority attain previous to migration, 
I cannot speak from direct experience, seeing that, as already stated, I 
have not examined any young fish; the calculated sizes set down in 
Table XXVIIc. allow us, however, to form a fairly reliable idea of the facts. 
By availing ourselves of the values denoting what length each trout was 
when the last winter-band was formed previous to migration, we get the 
following result :— 


Number of Fish which at the Time of Migration or Change of 
Growth had Lived 


Length in cm. 


8 winters. 4 winters. 5 winters. 6 winters, 


wl |e 


LITT TTL Lb omc Same | | 


_ 
omouo-o hp 


ea 


bo 
~J 
Leo tjae ga Ela 4 ob ie 


L Le] commroenl! rormloem! |) 1 i | 


Average length 
in cm.. , 19°5 24°2 28°1 80°2 


The length, therefore, varies between 18 cm, and rather more than 
80 cm., and these fish are accordingly, when transition to larger growth 
takes place, considerably larger than either salmon or sea trout. The 
sizes of the different age-classes have each their range of variation, which 
advances with age, as does also the average length of the fish. 


ON TROUT. 65 


On again examining Table XXVII. we find all the information we 
need regarding the age and growth of Mjgsen trout subsequent to migration. 
I have put in brackets the fish whose scales had spawning marks. In the 
Chapter on ‘‘ Methods’’ I mentioned that these spawning marks in trout 
do not seem to occur with the same regularity as they do in salmon. As, 
however, the surface of trout scales is comparatively small, it often happens 
‘that the spawning marks cannot be deciphered with any degree of certainty. 
Consequently I have not ventured to draw up an analysis of trout with 
spawning marks as a means of determining the average length and weight. 
The average length and weight has accordingly been based solely on the 
investigation of those scales which did not possess any spawning marks. 
On the other hand, when investigating the question of age, I have noted in 
brackets the fish with spawning marks, and it is therefore possible that the 
age in some cases may be slightly underestimated. 

If we now sum up the information we have obtained from Table XXVII. 
we get the following comparative statement :— 


Fish which after Migration or Change of Growth had Lived 


3 4 6 7 8 9 11 
winter. | winters. | winters. | winters. | winters. | winters. | winters. | winters. | winters. | winters. 


Number of fish. 6 11 55 58 (2) 10 (4) 8 (5) 2 (2) 8 (3) (1) qd) 
Average length 

incm. . 4 46°5 55 62 69°7 775 841 92°5 93°3 _ _ 
Average weight 

in hgy. . -| 17 18°9 28°1 41°9 59°0 811 93°5 99 — _ 


What chiefly strikes us in this statement is that we are dealing with 
fish which attain a much higher age after change of growth than either 
salmon or sea trout. While in the case of these latter, one rarely meets 
with fish which have lived more than three or four winters after migra- 
tion, or change of growth, the Mjesen trout attain to far higher ages. 
No doubt the number of individuals decreases with advancing age, still 
there must be quite a considerable proportion of the stock which are of 
great age. 

The average lengths and weights of the different year-classes teach us 
that growth is vigorous even at a very high age, and the ultimate lengths 
and weights of Mjesen trout resemble the values characteristic of salmon 
which have spent three winters in the sea. 

The scales of Mjesen trout, moreover, exhibit a peculiarity which is 
much more pronounced than in any other district in Norway which I have 
investigated, though probably it will be found to occur in many other inland 
waters. If we look at the scale depicted in Fig. 23 (Plate VIII.) we notice 
that the last winter-zone lies very near the edge. When the fish was caught 

8.T. 5 


66 THE AGE AND GROWTH OF SALMON AND TROUT. 


on August 19, it could not have been long since its winter-growth and the 
formation of the winter-band was completed. 

Exactly similar conditions appeared in all the scales I examined, as 
may be seen by referring to Table XXVIIc. If we examine the various 
individuals in this table, we frequently notice that the increase of length 
acquired by each fish since the last completed winter was very small 
compared to the total increase between that and the previous winter. 

As an instance we will take No. 88, caught on July 30. Its course of 
life has been as follows :— 


No. 88. Calculated Length at Completion of Winter-band. 
Measured Length 
on July 30, 1 2 8 . J ; x 
60 cm, 5°5 10 17°5 21°5 26:0 39°5 49 58°5 


Thus during its last summer the increase in growth only amounted to 
1°5 cm., whereas between the formation of the seventh and eighth winter- 
zones it had grown 9°5 em. 

Exactly similar conditions appear in all the specimens, and we may 
therefore conclude that summer-growth in Mjesen begins late. This is 
very probably due to the somewhat remarkable conditions of temperature 
prevailing in this lake. Its main source of supply, the Laagen, brings 
down a great deal of icy water until late on in the summer, and it is 
therefore late before the waters of Mjesen begin to rise in temperature. 

The temperature records published by Herr Hvitfeldt-Kaas* show this 
clearly. I give as an example the following from his series of records for 
the year 1909 :— 


Date and Temperature + O°. 
Depth in m. : 
March 11. | April 18. June 6. July 18, | September 10. | October 15, | November 18, 
5 0°60 1°40 4°65 12°50 12°70 8°30 5°80 
10 1:10 1°40 5°60 12°40 12°50 8:00 5°80 
20 1°75 1°85 4°10 5°90 _ 10°50 7°60 5°80 
50 2°85 3°00 4:00 4°50 5°40 7°30 5°40 


From these figures it is evident that the rise in temperature of the 
upper surface of Mjasen is late, and that by way of compensation it is also 
late in cooling down. Thus the greatest warmth is in September, and even 


* “Temperaturmessungen in dem See Mjgsen,” etc. Archiv f. Mathm og Naturv. 
Vol. XXVIL., n. 2, 1905. 


ON TROUT. : 67 


in November it is warmer than in June. These circumstances would lead 
one to imagine that we have here the cause of the late start in growth of 
the trout in this lake. 


2. Trout rrom Orner Lakes. 


~The material which I have obtained from other lakes and streams 
consists in the first place of some large samples from different localities. 
From these I have been able to compile comparative figures of the relative 
size in relation to age. 

I have, further, a series of smaller but carefully selected samples, which 
have been treated according to the methods of investigation and measure- 
ment described on pages 23 and 25, and the values thus obtained enable one 
to estimate the average lengths which the fish at the place in question 
usually attains on the completion of its first, second, third, etc., winter of 
existence. 

The values we get in this way, as I have described at length on the 
pages referred to, are sufficiently exact for purposes of comparison. 

Let us first consider three large samples which are respectively from 
Krokaa, Chaigijok above Rasti Lombola, and from Sandvand.* 

Samples from these waters have been dealt with in Tables XXXIIL, 
XXXIIIz., XXXIV. and XXXYV., from which we obtain the following :— 


so 
SE Number of Fish which had Completed 
88 
Locality. | 2 Ee 
z * 1 2 8 4 5 6 7 8 9 10 11 
z winter. | winters. | winters. | winters. | winters. | winters.| winters.| winters.| winters.| winters. | winters. 
Krokaa_ .} 110 _ 13 34 48 10 _— — ply ie — 
Chaigijok.} 108 | — 9 6 84 84 18 5 2 ee: es a. 
Sandvand .| 115 7 4 24 89 22 5 2 8 1 1 


Here we see that in all the samples we get relatively few of the 
youngest year-classes, principally because they are too small to take a hook ; 
and, again, another noteworthy point is that the numbers increase with age, 
to decrease once more as they approach the maximum age. This decrease 


* Sandvand on the mainland, a little south-east of Harstad, is a lake about one 
kilometer in length and 500 metres wide at its broadest part. It lies at a slight elevation 
above the sea, though sea fish are unable to get right up to it. 

Krokaa is a small river or rather a large burn which flows through a mountain valley 
into Skilbotten at Bronnoy in Sondre Helgeland. A high perpendicular waterfall about 
100 metres from the sea prevents sea trout from ascending it. 

Chaigijok. Themain source of Ovre Laksyand, Laksely, Finmarken. Rasti Lombola 
is a lake-like expansion in the lower sluggish portion of Chaigijok. 


5—2 


68 THE AGE AND GROWTH OF SALMON AND TROUT. 


may be due to several causes. On the one hand, it may be ascribed, 
perhaps, to insufficient material, though with waters so simple in character 
as Chaigijok and Krokaa this is not a matter of much consequence. On the 
other hand, it may possibly be due to matters connected with migration and 
mortality. 

A third point of interest is the relatively small maximum age in such 
small streams as Krokaa. 

As will be seen below in the statement of the average sizes of fish at 
different ages, this is different in all three places, though there is most 
resemblance between Krokaa and Chaigijok, where growth is slow. In waters 
like these, where development is so tardy, it is sometimes difficult to 
decipher the scales of the older fish, and itis possible, accordingly, that we 
may occasionally assign too low an age to some of them. 


Average Length in em, of Fish that had Completed 


Locality. Date. 
2 4 5 6 7 8 9 yi ae 
winter. | winters. | winters, | winters. | winters. | winters. | winters. | winters. | winters. | winters, | winters. 


Krokaa .| July 21— 
Aug. 8, 1907. _ 12°4 142 17°38 19°1 21 — _ _ _ — 


Chaigijok. | July 15—20, 

1909. — 12°8 15°5 174 19°7 22°3 25 25 — — — 
Sandvand | August 8, 

1909. 13°9 15°5 20°6 24°6 28°9 $2°2 84°6 40°5 46 47 49 


But this can hardly be of any great consequence, since the scales of 
many of the oldest fish are quite easy to decipher, and are without the 
thickened, irregular edge which characterises the scales of fish whose growth 
has practically stagnated. 

A similar low maximum age was apparent in almost all the lakes and 
streams which I have investigated in which the fish did not run large. 

We may take as an example the sea trout streams, which I have 
previously described, where we found a short term of existence (or 
residence) combined with relatively poor growth. In these we ascertained 
that in certain cases migration could clearly be assigned as the cause of the 
low maximum age, and the same reason may also to some extent be 
effective in the small inland waters where there are young, slowly-growing fish. 

Most of the waters where growth is more vigorous are characterised 
also by older fish. 

In the accompanying table I have compared the calculated mean values 
of the lengths of the fish in a number of lakes and streams.* 

We can thus compare directly the length of fish of identical age from 


* See Tables XXVIII, XXIX., XXX., XXXI., XXXITI., XXXIVB., XXXVzs., 
XXXVI, and XXXVI. 


ON TROUT. 


different localities, and I have for the 
same reason added the calculated 
values for Chaigijok and Sandvand. 

_ hese values show us that the 
growth of the trout in the first three 
or four years of its existence agrees 
pretty closely in the many different 
localities. It would appear that it is 
in the succeeding. periods of its life 
that a wider difference occurs. For 
instance, if we look at the values of 
fish that are six, seven, and eight 
years old we notice how great is the 
discrepancy in their growth. And 
this is even greater when we consider 
the difference in weight relatively to 
the difference in length.* — 

As regards the rate of growth, 
we find precisely the same conditions 
ruling that we found in the case of 
Mjgsen trout. All the fish, whose 
scales indicate a high age, had grown 
continuously throughout the whole of 
their lives. 

The trout of these inland lakes 
also furnish examples of the same 
peculiarity that we found in the case 
of salmon, sea trout, and Mjgsen 
trout, namely, that after a period of 
youth, with relatively slow growth, 
the fish enters into a later period 
with far better growth. In connection 


* In Table XX XVIIL, I have given an 
analysis which enables the reader to find the 
average weight of each trout of given 
length. The analysis is based upon the 
average of a large series of weights and 
measurements of trout from different locali- 
ties. There is probably some local variation 
in the relation between length and weight, 
and the analysis cannot therefore claim 
absolute accuracy for each locality, but it is 
merely meant to serve as a general guide. 


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The number of observations are given in brackets, 


70 


20 


' 10 


70 THE.AGE AND GROWTH OF SALMON AND TROUT. 


with this point it is remarkable, as was noticed before, that in the early 
stages of the trout’s life there is remarkable similarity in the rate of growth 
in different localities, and that the differences only appear at a later period 
of life. 

The fish in Sandvand, for instance, exhibited a typically altered mode 


WN 
NN 
‘s\ 


a 


\\ 


/ a 3 4 a é 7 6 9g 10 
ie re Or a). 
Fic. 30.—Growth Diagram of Seven Trout from Gjeddevand. 


of growth of the kind described, as will be seen if we examine the figures 
in Table XXXIVs. 

As a very instructive example I will mention seven trout I have 
obtained from a little lake in Finmarken. 

Close by the river Luostijok, whose stock I have previously described, 
lies a little moorland lake called “‘ Gjeddevand.”’ Itis separated by a small 
strip of land from the Luostijok, and its only source of supply is when the 
river now and then overflows its banks, and some of the flood water enters 
it by way of a shallow depression. The lake contains quantities of perch, 
pike, and burbot (lota vulgaris). There are, in addition, considerable 
numbers of very large trout, and so large that the Finns have to use salmon 
nets for their capture. As no streams flow into this lake, and the bottom 
is all mud, it is impossible for the trout to propagate there, so that the stock 


it 


ON TROUT. | 71 


- 


is dependent on such fish as chance to enter it from the Luostijok during 
a flood. 

The seven fish which I have obtained from this lake have been used in 
drawing up Fig. 30, in which the growth curves for each of the trout are 
shown. The unbroken lines of the curves denote the period of slow growth, 
and the dotted lines show when growth was rapid. 

The values from the Luostijok are, according to the comparative 
statement on page 69, as follows :— 


Calculated Average Length in cm. at Formation of each Winter-band. 


2. 2. 3. 4. 5. 6. if 8. 9. 10. ll. 


ah, 


44} 9 | 12°6 | 16°3 | 20°5 | 23°8 | 24°6 | 30°6 | 35°3 | 39°7 | 41°2 


Now if we consider the curves in Fig. 30 in relation to these figures, 
it will at once be seen that each single fish, at the period of transition from 
slow to rapid growth, was of a size resembling the corresponding sizes 
from the Luostijok, and that the average values for the unbroken parts of 
the curves agree very closely with the average values from that river. On 
the other hand, each single fish in the lake, after change of growth, has 
developed much more rapidly than the fish which remained in the 
Luostijok. 

There is not much doubt, then, that these trout have spent their youth 
in the Luostijok and entered the Gjeddevand during a flood, and have found 
there quite different conditions of food from what they were accustomed to 
in the river. Whatever their origin may have been, the fact remains that 
their growth history is clear evidence that these inland trout possess the 
same faculty of developing great changes in their rate of growth, as we 
found to be the case with salmon, sea trout, and Mjesen trout. 

They also furnish clear evidence as to the difference which may occur 
in growth even in closely adjacent localities, since the land dividing 
Gjeddevand from the Luostijok ver is not more than about 10 metres 
broad. 


CHAPTER IV. 


GENERAL CONCLUSIONS AS TO THE PROBLEMS CONNECTED WITH THE 
GROWTH OF SALMON AND TROUT. 


I sHauL now conclude by comparing the growth and manner of growth 
of the different fish described in the preceding chapters. 

In the accompanying figure (Fig. 31) growth-curves are shown for 
Salmon, Sea-trout and Mjesen trout of the same migration age. Included 
too, in the scheme, are curves representing a slow-growing trout (from 
Chaigijok) and a rapidly growing mountain trout from Osfjorden in Dagali, 
Numedal. 

It will be evident at once that the diagram illustrates very different 
growth and modes of growth. Still more dissimilarity would have appeared, 
however, if I had depicted several out of the many trout-curves, but I con- 
sidered it inadvisable to do so, for fear of making the diagram too intricate. 

We see, then, that salmon in their early stages have perhaps the 
slowest growth of all; the Mjesen trout grow relatively better than most of 
the trout family, and their development after change of growth most nearly 
resembles that of the salmon. . 

The sea-trout after change of environment grows rather less rapidly 
than the Mjesen trout. 

Finally, in the curve for mountain-trout from Osfjorden, we meet with 
a growth which is regular and vigorous throughout the fish’s whole existence, 
and in the burn-trout from Chaigijok we see the representation of a fish 
that grows regularly but poorly during a great number of years. 

These curves must not, however, be considered as absolute in every 
case. Indeed they do no more than represent a definite kind of growth in 
salmon, sea-trout and Mjgsen trout, for every one of which it would be 
possible to set up a number of subordinates, such as, for instance, curves 
for the three, four, five, and six-year-old migrants, or curves for their 
different localities in the case of sea-trout and salmon. 

We see accordingly that in conjunction with each of the type-curves 
shown there might be put down a number of others, which would still 
further emphasise the variations in rate of growth shown in the examples 
here illustrated. 

The diagram shows clearly that the old problems regarding the 
variability of fish, so far as this is expressed by size, may be reduced to the 


400 


40 


GROWTH OF SALMON AND TROUT. — 73 


two factors of age and growth, that is to say to difference in age and 
difference in growth; and we have now the advantage of being able to 
demonstrate in every case, with certain limits, what the difference consists 
in, and can resolve the variation into its several elements. — 

Any attempt to group the different ‘‘forms’”’ within definite classifica- 
tions on the basis of growth, will, in my opinion, at any rate with the 
insufficient material we possess, be impracticable, owing to the variations 
in rate of growth which present themselves. 


5a 


tL] 


1 


/ 2 3 4 5 6 7 8 q oO Od /2 Viotre 
Fia. 31.—Diagram showing Growth of Salmon and Different Trout.* 


It would therefore appear that so far as our present information goes, 
we cannot place reliance on anything but the manner of growth. We have 
seen in all our investigations that the fish grow in two manners. Hither 
they have a regular consistent development, vigorous or poor, throughout 
the whole of their lives, or else, like salmon, sea-trout, Mjgsen trout, and 
many other fresh-water trout, they change suddenly from a more or less 
poor form of growth to a totally distinct and more rapid growth under more 
favourable conditions of existence. 


* Laks = Salmon, Mjos-orret = Mjgsen trout, Sjo-orret = sea-trout, Fjeld-orret = 
mountain trout (from Osfjorden), Bak-orret = Burn-trout (from Chaigijok). 


74 THE AGE AND GROWTH OF SALMON AND TROUT. 


It is possible, therefore, to divide the fish into two classes, according 
to their manner of growth. 

1. Fish with uniform development (trout-like growth). 

2. Fish with altered development (salmon-like growth). 

A classification of this sort is perfectly feasible, and it will be both 
useful and instructive, inasmuch as it will always convey valuable biological 
information as to whether the fish had spent all its existence amidst 
uniform conditions, or has been subjected to very considerable alterations 
in its surroundings. _ 

Our investigations, then, have won for us this advantage: that the old 
question regarding the variability of the salmonide may be reduced to a 
mere matter of age and growth, a difference that we are in every case able 
to throw light upon. 

When, however, we proceed to ask about the causes of this difference, 
we find ourselves often at a loss. One may naturally enough conclude 
that the extraordinary alteration in development which we observe in the 
growth-history of salmon, sea-trout, and several other sorts of trout, must 
be closely connected with change of residence and access to better food. 
But it would be short-sighted on our part to assume that the quantity of 
food is the only deciding kind of influence that regulates the course and 
rapidity of development. Growth is by no means a simple phenomenon. 
On the contrary, it is the product of influences of many kinds. Undoubtedly, 
as I have previously mentioned, food plays an extremely important part, 
and possibly the most important. Still, even in this particular factor there 
are many variations, and there are, besides, quite a number of other 
influences whose significance cannot be disregarded. 

We can, for instance, mention quality of food, opportunity of obtaining 
appropriate food, variation in temperature, duration of winter (with which 
is connected the duration of the period of growth), the chemical composition 
of the water, the influence of topographical conditions, and the number of 
the stock. Last of all, there is the old question of race. 

Even if we can demonstrate that the old problem regarding variability, 
in so far as it is expressed by size, may be reduced to differences of age and 
growth, we are still faced with the possibility that underlying the great 
plasticity in growth which we have observed, there may be concealed a 
differenée in race, a hereditary difference, showing itself by a more or less 
pronounced tendency to rapid development, or, if one may say so, a greed 
of greater or lesser degree, by which is implied a greater or less power of 
absorbing and utilising food or conditions of existence. 

Many other influences might be mentioned, but it is as well to confess 
that we are, on the whole, not in a position to judge of their importance, or 
to assert positively what part they play. 


GROWTH OF SALMON AND TROUT. 15 


As a remarkable instance I will mention Carl Semper’s well-known . 
experiments with a species of snails, by means of which he demonstrated 
that the young of a particular kind of snail, Limnea Stagnalis, even though 
all other conditions of growth were identical, exhibited a widely differing 
development which corresponded to the volume of water with which each 
individual was supplied. When the supply of water exceeded a certain 
volume this difference ceased, and Semper explained this by the hypothesis 
that the water must contain some.ingredient favourable to the growth of 
the snail, but that a certain volume of water was essential to ensure that 
this ingredient was there in sufficient amount. 

It is not impossible that fish may be similarly affected. 

I will also, by way of illustrating another peculiar example of the exist- 
ence of different influences, : 
describe what I invariably 
found during my investiga- 
tions of salmon and trout. C 

The reader will perhaps 


remember that in all fish @g b 
which have undergone a con- 
siderable change of growth, 
this alteration occurs at no 
particular age, and that the 


time at which it takes place Fic. 32.—Relative size of snails, derived from the 
(the migration age) varies. same cluster of eggs of the same age, and reared : 


If, for example, we take fish 1.4"7"in “2000 com. of water per individual 
which have lived for the (From Semper.) 

same number of years after 

migration and group them according io their migration-age, that is to 
say, the age when change of growth commenced, and if we compare the 
development of each of these groups, we shall find one striking fact 
generally in evidence. The material in my tables is not always large 
enough for the necessary comparison, but in the one which follows I have 
selected some examples, and a reference to the tables will in any case show 
that wherever the size of the material is sufficient this condition of affairs 
is nearly always to be seen. 

The table, then, indicates that it is a matter of great importance for the 
growth of a fish subsequent to migration, whether it has migrated at a quite 
young stage or at a later period of life. The oldest migrants have clearly 
quite outdistanced the younger ones in growth during the course of the 
same period of time. They have acquired a far greater weight per individual, 
which must not be confounded with the difference in weight which might 
have existed between the oldest and the youngest at the time of migration. 


76 THE AGE AND GROWTH OF SALMON AND TROUT. 


Among salmon this initial difference is very slight, with sea-trout it is 
slightly more pronounced, and in the case of Mjesen trout a four-year-old 
migrant is on an average 24°7 cm., while a six-year-old is 30°2 cm. 
(see page 64), so that the difference is thus (cf. Table XX XVIII.) not more 
than about 100 grammes. 

The ultimate difference in weight is therefore not due to the slightly 
greater or smaller size at migration. There must be some cause at work 
which provides the older and slightly larger migrant with a capacity for 
growth and for utilising its surroundings, surpassing the capacity possessed 
by the younger and rather smaller migrant, for the former not only 
maintains its slight start, but increases it very considerably. 

However, these examples merely give us indications and hints that 
there are many reasons for a difference in the rate of growth, and these 
indications are chiefly noticeable because they show us that it will only be 
by working experimentally, and by separating and studying apart each of 


Average Weight in Hectos of Fish that at Migration 
or Change of Growth were Aged 


2 winters. | 3 winters. | 4 winters | 5 winters. | 6 winters. 


Salmon 2 winters after migration . 3h a | 40°8 44°8 — — 
Sea-trout 2 winters after migration . ‘ 3°7 51 6°5 8-0 —_ 
Mjgsen trout 3 winters after Eran or 

change of growth . < — — 25°1 29°6 34°3 


the different forms of influence which produce development, that we can 
hope to get a clearer understanding of these growth-problems. 

Ii will no doubt be extremely interesting from a scientific point of view 
to be able to go more fully into these problems, but what I consider most 
important at present is that every additional contribution to our knowledge 
of the causes of growth will have an important practical effect upon all 
questions of pisciculture, that is to say questions relating to rational 
utilisation of a given stock of a given water. 

So long as we remain in doubt regarding the reasons for difference in 
growth, we shall also continue uncertain how to obtain the utmost benefit 
from vigorous growth, or how to improve poor growth, or again, how to 
gain control over development in such a way as to make these animals 
subject to us, that is to say, by finding out the forms most suitable for 
pisciculture. 

Questions like these can now be solved by systematic experiment, and 
the results we have obtained will, I think, render such experiments far more 
successful than they might otherwise have been. 


GROWTH OF SALMON AND TROUT. 77 


Merely to mention one form of pisciculture which is of the utmost 
importance over here, namely, the better utilisation of all the possibilities 
of our fresh water lakes, the knowledge we have acquired should be of great 
assistance. 

Hitherto the greatest obstacle has been that it was impossible to 
control the stock. 

The methods, however, whose results we have here discussed, should 
cause this difficulty to disappear. 

We can now examine age and growth, and thus obtain the means of 
estimating what results are derived from the different measures adopted, 
such as turning out young fish, preserving the waters, and regulating the 
fishery. We can also keep a better check on our experiments by tracing 
the age and growth of the fish in general, as well as also each individual’s 
growth-history. 

Just as the forester estimates his forests by borings and calculations of 
growth, so, too, we should be able to estimate the stock of fish in the water, 
and endeavour to set up a plan of operations based on assessments of age 
and growth. No doubt it has not yet been proved that this is possible, but 
our endeavours should be made in this direction. 

Bound up with the problem of rational utilisation of our waters is 
the question of recruiting the stock. 

Some of my results have led me to believe that it may be an advantage 
in many waters to turn out fairly large fish in place of small fry. 

This question arises in all waters where the fish in their young stages 
have a poor development, followed subsequently by splendid growth. 

Lake Mjesen may be taken as an instance of this. If we look at the 
table on page 76 we find that the trout which began their vigorous growth 
at the age of six winters, grew far better than those which commenced at 
an earlier age, so much so, indeed, that we should almost gain one kilo. 
by employing the oldest fish. The difference in weight which we finally 
get is far greater than the slight difference existing between the weights of 
the fish when they first commenced their vigorous growth in Mjaesen. 

It might be worth trying whether it would pay to turn out such trout 
at the most favourable age, and we could mark them and watch the results. 

Another example is also worth mentioning. At Trondenes Manse 
there is a little shut-in tarn called Laugen, where there used to be no fish, 
but which swarmed with water-fleas (Gammarus). Some trout-fry were 
turned into it, and grew capitally, but they did not increase in number, and 
were gradually all captured. 

Close by the manse there is a little burn, where there are quantities of 
the ordinary poorly-developed burn-trout. The priest’s sons used to 
amuse themselves by catching these small trout, and turning hundreds of 


78 THE AGE AND GROWTH OF SALMON AND TROUT. 


them into the lake, and I have caught some of them and examined their 
scales. The results are quite remarkable. One of their scales is to be 
seen in Fig. 33 (Plate X.), which represents the scale of a trout 36 cm. 
long that weighed 650 grammes. The trout has first grown very poorly 
for three years, and has then spent a summer in Laugen, where it has 
developed enormously. After the usual winter stagnation, the fish has 
passed through another summer with again enormous growth. 

Similar illustrations of growth were afforded by all the 21 fish from 
this lake that I examined, and the following table shows the averages 
I got by my investigations :— 


Average Length and Weight when Caught. 


Calculated Average Size before 
Transference, 
ist summer in Laugen. | 2nd summer in Laugen. | 8rd summer in Laugen. 
Length 14:4cem. . 27°9 cm. 85°4 cm. 45 em. 
Weight about 0.25 hg. 2°7 hg. 6°6 hg. 11°0 hg. 


This is a clear instance of what beneficial and valuable use has been 
made of these small slow-growing and relatively worthless fish, and it 
shows how well they have been made to grow by transferring them to 
Laugen. 

It is also interesting to look at the weights they attained in their first 
and second summer, compared with the age and weight they had at the 
time of transference. 


Average Weight of Fish which when Transferred had Completed 

2 winters. 8 winters, 4 winters. 5 winters. 
At transference * . 9 gr. 20 gr. 23 gr. 438 gr. 
1 summer in Laugen . 2 hg. 2°7 hg. 8°5 hg. — 
2 summers in Laugen 4 hg. 6°2 hg. 7°2 hg. 78 hg. 


This second table shows us quite clearly that it is apparently an 
advantage to turn out older fish, and it might be well worth while 
experimenting with the various possibilities suggested by these results. 

I have given these instances because they seem to me to indicate some 
of the lines along which experiment and study of growth should go. 


* Found by calculating the average lengths of the fish at time of transference (from _ 
measurements of the scales), and translating these lengths into average weights as per 


Table XX XVIII. 


GROWTH OF SALMON AND TROUT. 79 


For other questions connected with development, other modes of 
investigation will have to be discovered, and in particular questions of race, 
and questions dealing with tendency to growth, or a hereditary capacity for 
growth, will naturally have to be studied in such a manner as to ensure 
complete control and isolation of every influence. 

In conclusion I may add that there is no doubt that the methods of 
investigation which have been discussed in this.work will be of general 
benefit in many directions in experimental and investigation work, 
inasmuch as they have enabled us to penetrate into the secrets connected 
with the growth and the life history of every trout and every salmon more 
deeply than has ever been done before. 


tie : | eat ie Oe fe 
Brian th rio ee tn Neca a! pa 
a OL he Btls 
70 5 aA alee a 


ARIA? 
Ae es 


Table 


9 


44 4 deewn das38 x. 


XX. 


XXtT. 


CONTENTS OF THE TABLES. 


Pun Caen 


SALMON. 


Age, Sex, and Length of Parr and Smolts from different Rivers. 

Age and Length of 19 Salmon from Sandeidfjord, Ryfylke, July 238— 
August 21, 1908. 

Age and Length of 676 Salmon from Christiansand. 

Age and Length of 261 Salmon from Moltuen, 1908. 

Age and Length of 244 Salmon from the Orkla, 1908. 

Age and Length of 89 Salmon from East Finmarken, July, 1908. 

Average Weight of Salmon in relation to Age after Migration from 
different Parts of Norway, 1908. 

Age and Length of 1,612 Salmon from Christiansand, 1909. 

Age and Length of 187 Salmon from Moltuen, 1909. 

Age and Length of 284 Salmon from Buggnes, Varanger, 1909. 

Age and Weight in Hektograms of 1,612 Salmon from Christiansand, 1909. 

Age and Weight in Hektograms of 184 Salmon from Moltuen, 1909. 

Age and Weight in Hektograms of 284 Salmon from Buggnes, Varanger, 
1909. 

Sex, Length, and Age of 48 Salmon from Fosen—Senjen, June 30— 
July 2, 1909. 

Sex and Length of Spawning Salmon from T.aerdal and Drammen Rivers. 

Sex and Length of Spawning Salmon from Aaen-sire River, years 1886— 
1897. 


TROUT.* 


Age, Length, and average Weight of 192 Sea-Trout from Trondhjem, 
June 26—29, 1909. 

Age, Sex, and Length of 59 Trout from Dalgs River, Utskarpen, Sep- 
tember 1—10, 1907. 

Age, Sex, and Length of 82 Sea-Trout from Utskarpen, Ranen-fiord, 
September 1—10, 1907. 

Aggregate Age, Sex, and Length of 142 Trout and Sea-Trout from 
Utskarpen, September 1—10, 1907. 

Age, Sex and Length of 43 Trout from Aag-vand, Rods, Nordre 

Helgeland, August 12, 1908. 


* The state of the sexual organs is, where examination has taken place, indicated partly by letters : m = mature, 
im = immature; it is also sometimes indicated by figures : 


2 = small ova visible, milt somewhat swollen in front. 
3 = roe and milt nearly half as long as ventral cavity. 
4 and 5 = sexual organs nearly (4) or wholly (5) filling neutral cavity. 


Sexual organs with less development than 2 are signified by— 


84 THE AGE AND GROWTH OF SALMON AND TROUT. 


Table 


” 


? 


XXII. 


Age, Sex, and Length of 95 Trout from Kvern-vand, Neerg (Namdal), 
July 6, 1909. 

Calculated Lengths at Formation of different Winter-Bands of the 
Fish in Table XXII. 

Age, Sex, and Length of trout from Mélnbugtelv, Agdenes 
(Trondhjem District), July 4, 1909. 

Calculated: Lengths of Fish in Table XXIII. at Formation of the 
various Winter-Bands. 

Age, Sex, and Length of 55 Trout. OsRiver1. Tysdalsvand, May 15 
—18, 1909. 

Age, Sex, and Length of 155 Trout. Os River 2. Foot of Bergstgvand, 
May 19,1909. 

Age, Sex, and Length of 132 Trout. Os River 3. Bergstévand River 
Mouth at Sand. May 10, 1909. 

Age and Length of 171 Trout from River Laagen, Lillehammer. 

Age and Weight of Fish in Table X XVII. 

Calculated Lengths of Fish in Table XX VIL. at Formation of different 

. Winter-Bands. 

Caleulated Lengths at Formation of different Winter-Bands of Trout 
from River Laagen between Langesjgen and Hglen (Numedal, 
Hardanger-vidde), August 26, 27, 1909. c 

Oaleulated Length at Formation of different Winter-Bands in 8 Trout 
from River Laagen below Hglen (Numedal, Hardanger-vidde), 
August 23, 1909. 

Calculated Length at Formation of different Winter-Bands of 20 Trout 
from Lake Hglen (Numedal, Hardanger-vidde), August 27, 28, 
1909. 

Calculated Length at Formation of different Winter-Bands of 9 Trout 
from River Djupe (Hardanger-vidde) August 24, 1909. 

Calculated Length at Formation of different Winter-Bands of 6 Trout 
from Lake Ossjgen, Dagalid, Numedal, September 7, 8, 1909. 

Age, Sex, and Length of 79 Trout from Krokaa, Skilbotten, Brgnng, 
Helgeland, July 21, 1907. 

Age, Sex, and Length of 31 Trout from Krokaa, Skilbotten, Brgnng, 
(Helgeland), August 8, 1907. 

Age, Sex, and Length of 115 Trout from Lake Sannavand near Harstad 
(Nordland), August 3, 1909. 

Calculated Length at Formation of different Winter-Bands of the 
Fish in Table XXXIV. 

Age, Sex, and Length of 108 Trout from Chaigijok (Lakselv, 
Finmarken), July 15—20, 1909. 

Caleulated Length at Formation of different Winter-Bands of the 
Fish in Table XXXY. 

Calculated Length at Formation of different Winter-Bands of 15 
Trout from River Luostijok, July 17—September 4, 1909. 

Calculated Length at Formation of different Winter-Bands of 10 
Trout from Lake Gagavand, August 27—September 18, 1909. 

Average Weight of Trout in Relation to Length. 


85 


TABLES. 


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86 THE AGE AND GROWTH OF SALMON AND TROUT. 


TABLE IL. 
Salmon. Sandeidfjord. Ryfylke, July 28—August 21, 1908 
Bis 
Winters after 
Migration. Winters before Migration. 
Birth-year. 
2 3 4 
Length in cm. Total. 
1906 1905. 1904. 
22 1 —_ 1 2 
23 2 2 —_ 4 
24 1 1 _ 2 
25 2 2 1 5 
26 2 2 — 4 
27 1 _ 1 2 
Total 9 7 3 19 


TABLES. : 87 


TABLE III. 
Salmon. Locality : Christiansand. Date: Season, 1908. 


Winters before Migration. | Winters before Migration. Winters before Winters before 


: Migration. Migration. 
Birth-year. Birth-year. Birth-year. Birth-year, 


Tot. >| Tot. Tot. 


3 
: 
g 
: 
3 
S 
: 
3 
g 
S 
2 


87 


& 


bo 
(or) 
~I © ~T Co tS 
— et eS HT Or OD 
SCOCCO REE 


—— eee 


= bo 


m noo SH 
= | 
es 


8 

Seper’ @ SchS eee se aer ite ee se 
REAR ee Sor2 o> TRS ER RE SSR Se 
BCSRSSRSRES PERS RRR e ee 
BERR ER SRR ESE PERRO ee eee 

Seber es 2ees eo ase ek 
BSSSSE GSR eeRSk ey EL See eRe SS 
| ChE PP EEE EEG ER BREET 4 
ee ea ie) oi es 2 beim Bigigi Se S285 sie) 
PPP EP EP EEE EP EP EP EET EPP 
ls ddd dated dood td dott otal 
BSISSIIII IIE tl iii 


Beep eee 


Be kf es Gd al 
14 ee et EPP EPH 


mab mi be oe | CO He CO OD Cr 


DEMS SSS OOO MMOH OMA 
BESESSSsSeaeesusssseeseesss | 
-_ 
-_ 
Butewe iss 3 


Tot. | 676 || 118} 101) 1 


net 


im cm. 


ior) 
-_ 
bo 
(i) 
ce) 
2) 
or 


265) 1 


[o>] 
-_ 
© 
a 
Oo 


26 (25)} 1 


bo 
= 
i) 
~~ 


366(17) 


13°2 
(64°9) 


| | 


98-7 
(74) 


bt) | PETEPETEET EPP LEP E Et bbb tid 


11 | 
L || 
Lt | 

1 | 
Lt | 
11 | 
| || 
Bite 
11 | 
It | 
Lt | 
| | 
It | 


N.B.—Fish with spawning-mark in brackets. 


88 THE AGE AND GROWTH OF SALMON AND TROUT. 


. Salmon. 


Locality : Moltuen. 


TABLE IY. 


Date: Season, 1908. 


Winters after 
Migration. 


Length 
Number of Fish 
Examined. 


Winters before 
Migration. 


Birth-year. 


Winters before Migration. 
Birth-year. 


Winters before Migration. 


Birth-year. 


4 


g 


E 


3 


E 


for) 
Pas 


Pabebchel..!* Lebehel LLLP EPR RP RT TE ETE EI 
PPPPELEPEP ED EE EP EE EL EE ELITE 
PET ee ete eh ee ie 


PETE Rb td bt ore core te 


PTT PREPPED BeeeRERE beer PP Pr 


LPR RR RE Ba re he 
LT EEREPER ER ERP E PER ER EC UEEE ERI 
LEP EE ERE CEES EE PE RET ER EPPEE EE 


— 


ome = 


a 

RPOAnNowand hee - 
i i ain ~-—o_ 
——-- 


~~ 
_ 
~~ 


= » 
tt Oe: Se 


| 


=PEEECEECEEPECECEL Teer eer 


© 


_ 
oo 


— 


28 
54°9 


8 4 5 
Tot. 

1903 | 1902 | 1901 
Se (1 
ag ee Pe ) 
ee 
oo "| re 
St} ' 
Leen ook ae 
SS Se 
ay oa eek 
SS aetk 
ao =} She 
Sas a Le oe 
at | 
a ad ee he 
oy Ed be 
120 | 26 | 3 |166(3) 
ot. |- ee 
—|—|—| (60's) 


@ 


ne 
bo 
oo 


56 (7) 


95°6 
(82:0) 


N.B.—Fish with spawning-mark in brackets. 


> 


~ 


TABLES. . 89 


TABLE V. 
Salmon. Locality : Orkla. : Date: Season, 1908. 


"naan 2 fe 
, Winters 
Winters before Migration. | Winters before Migration. ] Winters before Migration. before 
4 “an Migration. 
g Erg »’ Birth-year. Birth-year. i _ Birth-year. 
s ws Birth-year 
a ¢ 
Es az 2 38°) 4 5 2 8 4 5 2 3 4 2 
si Tot. Tot. Tot. Tot. 
1905 | 1904] 1903 | 1902 1904} 1903} 1902} 1901 1903 | 1902} 1901 1902 
43 - Scenic (Ramesil Wiescors't Ais Games) | hocmmelll | ammmied (usmuneal Conceal ) amma | eum Gemalto — |—|— 
46 2 OES) | en ems Cems ea ey, a] | ees een eee | Sly es (eee eee aM eR! AE 
49 1}y—}—ti— |} — | ot — | — ] — 1 I wall eure Gane —- |— }— 
4-44 bh bo | a te | 
55 6 | — |} — | — |} — | a — | — | — | —  — JR — |j— |; — 
58 4M pas fame a ee ff ef —) | FR 
61; 4/}—}|—}]—|]—]| 4J/—|—J]—!|—|—J-—|/—J]-—| — |-—|- 
64 45 — }— | — J ee  — I — I Oo I I — |—)jp— 
67 24—}— | — Fe  —  —  —  — I | Oo ee — j—j— 
ee ee eed Nt eae a ee ee ee ee ee ee 
73 16 |} — | — |} — | — } om EK | —  — 1 16 J — /— I] — |—}— 
76 29 |} — |} — |} — | — | — J — } — |] 29 J I — j|— | — 
79 20 |} — |} — |} — | — | de I — 1 119 Pe I 1 — |— 
82 14 |} — }— | — | — J J — | — J ] — 112 J — I — I 2 — | — 
85 30 |} — |} — |} — | — J — | — | | 28 J | I 4 (1) —j— 
88 20 }— |}— | — | — | — JY —  — 1 — 1 118 F— | |e 2 —a3-— 
91 18 |} — |}— |} — | — | — JF — | — I — | 1p 6 (1) — }— 
94 18 |} — }— |— |} — |} — FJ — | — | — | | OB Y— | — | — |} 10 3 — 
97 21 }— | — | — | — | — I — J — I] — I 1 ts] 19 (1) (1) 
100 12 |} — |} — | — J — J I | —  — 1 — I — IT — 1 1 | 12 —|— 
103 Ti—}— et et I — I I dS I 7 —|— 
106 3 Pm te Oe I I — I I — I I I 3 —_—|— 
109 27—}— | — J — FH  — J] — 1 I — TI I 2 —};— 
112 2)—}— | — Je ed — I — J — 1 — I — TI I 2 —j— 
115 1 y— | — J — J] — J] — J — J — IT —  — I — I I I 1 —|— 
118 mH oe oo ee os I Oo ed I OI —_— |— | — 
Tot. | 244 2|16 1 |— {19417 | 109} 26 | 2 | 15114 | 54} 5 | 71 (2) 1 (1) 
Average || — |— |— |}— |— J— | — |— | — |— J] —|—|— — |—|— 
length —|—|— |— | 56 —}|—|}— |8l1}J—|— |— | 969 | —|— 
in cm — —h1 —{—|—|-—|-— — { (88) — 


N.B.—Fish with spawning-mark in brackets. 


90 THE AGE AND GROWTH OF SALMON AND TROUT. 


TABLE VI. 
Salmon. Locality : East Finmarken. Date: July, 1908. 


Winters after : 2 8. 4. 
‘ Winters ipefore | Winters before Migration. | Winters before Migration. eos 
on. 

Birth-year, Birth-year. 

§ | Birth-year. Birth-year 

ak 3 | 4 2is8f]4]s5 2is8i4/65 4 
A Tot. Tot. Tot. Tot. 
1904] 1908 1904} 1908 | 1902 | 1901 1908 | 1902] 1901 | 1900 1900 
6554 i eh ee P| Bb beet he Pa 
FDI PSR A) ae A Ol ES | meg ED! nea | TI PG 
Pt a SED, FEED TG OE | NS I GR VA PL PREC HE) ea YY PA 
7) aa PR NS ERIS | EL GRY SS AM MER PRR) GRO GU HH, 
eh BE PRES) MT RU: SG EN AIR VR RR RR Pe fH PE Ips es gS Fm 
Si Sia Oe | | ee 
Se Mes es pL OD a Oe | RE AE PAN PA SA AE RE: PE Mo 
By BARS) RE ae amy ee arid ET, AY Sa PO eae AE PE phe) Pee | By ebay) joc « 
RANE sy CEG GE RP ee, | RE Pa RG RY YE PhS Ha ie Ge 8) me 
BOA Be Ee cei beth Poe Are flame |B feo Lael ate ge dae 
PB Be Pe EG NAS RS Eee |S RP GS PS je ES eRe ELD Se 
7B UB ee) SA CERES VCD Bsr EL A PM Rp) TG Ee LE | Pa yy Fed 
BPS Es SA ASI Se RE RR CAM 9 | Ep HR ak) WB Ypres, RY 
O15 84a i | 8 | ee 
eh Bho Beg I 
Oba) 80 8 44 te | — fr et ee 
id | Mae bak eee ft On Be 
Od 118 We) aaa ae 
Ora 3 We ee Pt ees tee 
SG Mie age) (RGR A A is A | MS PAR NR RE A GES sang (RY #9 
FR ME GE ER BR PRE RUG (a | RRM MOT UR PRE BRED RE ge “yA en 
CG Se ERD Re RT ies Sag VN VA NO) Py ARE) SE) te IY PEL vo 
NE oe ae eh een Pin |) | ff a fink Bee ee i 
Bh Mae A RS eA) SES A PR RRS A SRAM RR OL RE ESS 9 
LS Ty ET BIER ERE BO A el AR PM UN PRE Wy SS. Bg WN 
Tot 89 91 7] 16 2110; 6] 3} 21 5 |33 |} 9] 1/48(1)] 2 2(1) 
Ave ee PAE een, Wey (ie, ceed eee eee ee me Yams, (mee, Hecet: P Y , 

len se eS 2 A RS NS NE PE Pe LY 8 
in cm. — 58°5 | — 759 —|— | (79) J— |] — 


N.B,—Fish with spawning-mark in brackets. 


TABLES. 


TABLE VII. 
AVERAGE WEIGHT oF SALMON OF DIFFERENT ‘AGEs In GRAMMES, 1908. 


91 


Age after. Migration. 


1 winter, 2 winters. 3 winters. 4 winters. 
Locality. 
Without | Without With Without With Without | ~ With 
spawning [| spawning | spawning | spawning | spawning | spawning | spawning 
mark. mark. mark. mark. mark. mark. mark. 

Christiansand 1,675 3,972 2,735 11,162 4,108 —_ 7,778 
Moltuen 1,793 | 5,091 2,550 10,593 6,750 21,500 _— 
Orkla . p ‘ 1,816 5,895 — 10,503 | - 8,350 — 10,300 
East Finmarken . || 2,047 4,909 — 9,629 5,300 13,250 8,600 


THE AGE AND GROWTH OF SALMON AND TROUT. 


92 


“syoyoeiq Uy yvur Sayuaeds YQIA YSII—aN 


—|—]J—|—|—] —] (92) | 22) | (1-92) |(¢-e2] (3-19) | — | (o9) | (8-19) | (%-19)} — | — |— | — | — fy he 
—|—|]—|—|]—|—] ¢16 | 946: #16 | 818] SL [81h] 92 | GEL | GIL [6-F9| 6-99) 1-99/6-F9/ 6-69! oseroay 
(1) | (1) |) | (1) 1) | (@) | (o#) 19] (or) 6 | (ze) te] (@) rt] (es) 998] & |(z) 60} (Sz) 999\(6)9LT] 8T9| 4 | 94 | Leh) 86 | ZT9‘T| “FOL 
—|—j—|—| -t—] — FAK | ame oe oo PO voi 8) Ginuccites Sane Mined ews aes ances, Mogae 
sed be? es louel ae as le eae Sere ee oS narkt Thies cea Some “neath Seat ek Goad 
GiGi i—|-a-] 8). 80 meh tr | | ee ae 
(aie PL 2 ets Decacaie! Meets Nee gee as et ete ao” OE 
soe a | Bh te rad Hane Ok 2S AS eS hae ef ee ee ae an) el oe ee 
|i |— | a  el 5S Bi Rceatey Sr: hee OP te pe fet ee ROBE 
—|—}(@|—|@MiM} |] Tt Si Se = eer ae oe ee el ee 
— | HD ar Teel eb ae ee oat! Tasty Spaz tesa Dene iastet tame Sie i 
oad toned tamed lasel eae: fecal (ee oad 2 32 SS Se oe ae I Si ee ea ee ee ee 
=p — | SI oe ry s ots g craic! ‘mune damick’ see! inane Gere C190 
[aie | ar ane &)9 I Grif |» Mos ss | Sa eee 
iil oe ee 9% | 1 or Ts 18 Saf ee efor peer | aml OF “1 Ee 
—|—|—|—|—|—],®F | Wt | fie I FIT] T | 8% GL fe Geena Maasai Saaatet femog faaciny fe * 
| 1 ee OlR al 8)% I 9¢1| — | 8I ia Mint | pr ae 
—|—](1)|—|— |] lent tt 6) {|(z)t | (t)eer] t | of |(t)eet | es }— |— |— | — | — | 400 |& 
Se | ek Ti Oe GS (I (9 = 9bI) I | &I £6 ry (ae Cena Gane Peewee fle h- 
=e ree me pee aT eee (Dah — $5) 60 — | or |(e6¢ OLS [SOT og IE 
cee te! “seed mn Ga Ged (T ~—- { — | (esr | Tt ¢ |(9)82 |(e)#r}s |— |t | Tt |— | 6¢ | 
| f= | et ey | — {6 gar |e |e |— | at | 2a }s | a |t9 
| —j— | — | Sarre Ste SES ‘2 L |— |r {faa |@ PI] 9 | 1G | SOT} L |] 991 | 89 
—|—jJ—|—]-—|-}. — | — - -— --—] ot [-—] — je — | 02%; 1 | 02 | 91} 98 || Laz |¢¢ 
—|—I—|-— | = Rs] asl SR Pad — | — JL9T|} Tt | Gt | FIT] OF || Lor jee 
od aes cot tae few lots tee ae — |— Ji }|—|t |er |i |e 
| — | eles se tee — |— }6 |—|t |9 {8 |e |% 
=) fh — | — | ee ees eee od —|— |e |}—|—]% |— Vs | 
006 0061} TO6T) O6TE 3061 $061 FO06T S061 806T FO6T 906T S06T | FOGL | SO6T | 906L Sy 
40L |——1"90, "40L ‘70L ‘901 ge | tf 
8 oly|es : 8 F 9 » | 8 3 o | +] s | s Ee 4 
qwok-W31G] saeo 2 
*"MOTpelsIy a —— “reed-Y4.1L sve 4-WIIg ; “v0 4-41 z8 
Fea Ftoen 810} UM "UOYIBIB FE O10J0q S1OFUT AA “UOYBIBT O10Joq 8107UT MA "UOTPBIBTAL O10JOq $10}UTM He : 
“uo 
9 ¥ 8 z I Phen 


“606 WosBeg - ofEq 


‘puvsuvystyy : Ay1[B00'T 


THA WIdvi 


"MOUITBS 


TABLES. 93 


TABLE IX, 

Salmon. Locality: Moltuen, Date: Season 1909. 

1 2 8 4 5 
Winters before Migration. | | Winters before | winters before Migration. Meee 4 eee 
Fy 2 ied wis) ae: pec haan Migration.} Migration. 

o 4 “year... * .  Sbirth-year, 

A ¥ ‘ Birth-year. y {Birth-year.[Birth-year. 
eldala]s [as 2/3 | 4 2/8 | +4 3 8 
aden Tot. -—— Tot. Tot. Tot, Tot. 
1906] 1905 | 1904] 1903 1905 | 1904 | 1903 1904] 1903 | 1902 1902 1901 
31 -b+- 9 [ails feed bea: ff Dot fo belo 
Ota 4-7 Ohl) Oise Pee Fa ee] ee 
10-0 Fao eee oe ee Se ee eo eS 
169° B+ -6i) Gl aed ee a Se pee | oh ee 
ae Bt 9:) 4) | ee eae ees pos Pat ad fe fe ee 
ht) 2) a ee Bah ook he | a ff 
7 RA ee ee eee 6 Ra Serie. [es ot a 
ob fac: | sat] ce] ee Pega Pl Set Pe pl gu) rd ee 
0 i ee ee ee ae Oe ens Ce oes. peed pene ba a pew 
ES) bo eR einag 99 LG Let iS hp 
NE ee ee a ae Dele eo eee Presi: oo 5 eo 
i a ee) 8 ao @) tag ir 
Mae b= | ee a] SEOs a1 BO Be ee 
Hae fa Ret a | ah lia 1B | ee a ee 
AiG) | | aes bh a(t) PF — [20 49) |} 2 [12-29 — | Hf a S 
a Pa ee | ea | -t Oa — 1 — 4 — | + 
O(a eee eee) ay eee a 410 |(4)|(4)}—|— 
Et Ree cosy peg ek) ey ey ee ee 215 {(1)|(){—|— 
Ap po LL Pee P| tt hg AG ae Cones oe 
sts fe ee i at ey a2 4—1—1 M10 
oes ee ees Pe es ot fs wee Po aes OE 
Be ee) a ge en ee ee ee ee ee ee a ee oe ee ee 
5 |27/11| 1144] 5 | 52/18 | 75 | 1 [35 (3)|18 (1)}54 (4)} (5) | (5) | (2) | (2) 
[ee eer fe fae 1 08-84 T= 1 Oe ~wifesa 

60-8|54-7| 58 | — |56-1169'8|75-6)77'5)75-4] 96 |(91-3)| 97-2 |(88-8)} — | — 


NB.—Fish with spawning mark in brackets. 


94 THE AGE AND GROWTH OF SALMON AND TROUT. 


TABLE X. 


Salmon. Locality: Buggnes, Syd-Varanger. 
Date: Season 1909, up to the beginning of July. 


Winters before Winters before Migration. Winters before 


g |» 


g 
3 
: 
g 
E 
3 
g 
g 


2 
2 
z 


BESSECSSROSESR St I EeR eae A 
PITT TELL TT LL eon emro lL ETT TI 
PPTL EE ET ELD eee eroroe dP ETT EA 
BeReeeeeee. eee 


LLL TTL TTD be commrccomel ITT dt | 


2 


ad 


sil eSeel Slee a eed 
ee ee | pl Dee 


Seopee 
lst iri 


Pasiett-t tis 


-—_- 
_ 
~~ 


—— 


Sa el a eee EEE Te 


— i 
—_ ee et 


~ 
ao 
Ld eee 


i i i iin 


bop 

- et #71 Gr bo bo 
— bo 

to) 

-~—_ 

— 

al 


— 
RRR OnIm 
l 14 
Spee cses! | Ili tl ttl 


LL dot erormmm I TIPPETT Pili 
wo 
oa 


eit beets leh eee erent 
Ppp) aeees 


i 


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to 


os 
—e=\ 
ww 


- 
—" 
~— 


—“~ 


Beet rsp ee GheMgasce sates 
—~ 


— 


_ 
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© 
(ev) 
4 
ao 


108 (49s (3) 15 |227 (7)81)|1 (10)} 2 [3 (18) 


— F— ) —- ST _— 


89-1 


i 
i 
| 
EE 
M1 
i 

S| 


Tsar's 88-7 |s9-5 |s9-5| (76) 


(2 


e 


(3 


Ss 


(103°8) 


N.B.—Fish with spawning mark in brackets. 


95° 


TABLES. 


*“sjoyowIq Uy yIwu SaruMeds YIM Ys—"g'N 


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(18) 18 | () TT 


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(6-22) | — | (61) | (1-22) 
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(4e)¢¢s'| & | (@) 60T'| (Sz) 99¢ 


(8.42) 
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96 THE AGE AND GROWTH OF SALMON AND TROUT. 


TABLE XII. 
Salmon. Locality: Moltuen. Date: Season 1909. 

Winters 

after 1 2 8 4 5 
Migration. 

é || Winters before Migration. Winters efore | Winters before Migration, sin. betveser iy 

B.; Birth-year. Birth-year. oe 

@ 3 Ta eee: apie feictn-year Birth-year. 
is] ry 

ia E 2{s|41|5 2/3 | 4 2 3 4 3 3 

& |e Tot. Tot Tot. Tot. Tot. 
E 1906] 1905 | 1904 | 1903 1905 | 1904 | 1903 1904} 1908 | 1902 1902 1901 

y 1 ge a | ae ee ee po fe ae ee Pe ee ee 
14/18 }—/11) 2)— 118 f— |— j}—J}— t-| — — yg Ep a Ne 
21127 138)15) 8] 1)/27——{|—|—|—f—-| — bone a Pee, Omer” 2 
28 4) 1 1), 1(/— 1 dsy—lo1/—)}] tr] — — ie. Pee ba ae 
85 |-16 1 f—  — | ep 2 110) 2)14t—)-— —_ ee ee Oe 
42 |18 }—|— | — | — | — J 2) 9) 7/18 iI— | — — pea | eng peed! poeaay Bm 2 < 
49 | 14 |} —|— | — | — | — J — | 18 | 1/14 I —)| — — eR | SRE ene) Semen! | 
56 | 16 }—|— | — |— | —] 1/12] 2/157—-| — |] (1) GQy—|—]—|— 
63 ot — 4] 3 Tt Ti—t — | 2. aie ois 0 fed A 
70; 3}/—j—/—}|—|— J— | — | 2 | 2t—)} 1 — ii mae, Ps pee 
77 9 }/—}|— J — | — | — J— |] 2I—] 2I—)} 40) 2 PER Se Sy py 
84 | 10 |} —| — |— | — | — F—_ | — | 1] 1 —| 6) 2 Sie — 4 oe Be 
91 8 }—|— |— | — | — F— | 1 | — | 14 3 7 Sy AEN Pe 
98 | 8 }—|}— |— | — | — J— | — | — | — 1-1 6 (0) 1 7(14y¥— | — | —|— 
105 | 9 }—j|— |— |— |—_ J—_ |—_ | —_ |---| 4 2 6 3)1(3)1— | — 
419 | 89 —|— |— | — | — F— J — | — | — 8a. 18) il 
119 | -4 J— | —J— Je | |S | — | — bate 41. 18 ial @i—l— 
126 | 5]—|—|—|—|—]—|—|—|—]-—/2 [2 |4 J—J—-I@Ml@ 
198 7-3 1 PS ee et | | — Tae TY 2 a ee ee 
PG aS Pe ae eS ee ee be ed Pe ee 
147 | 1 J} —|— | — | — | — J — [| -— | — ee) 1 — Fr | ee 
PoE Hi 08 Se TR ERS SRE RS) SS EE ER Sy NERS Loe 
161 |} — }—|— | — | — | — I — I — I I I en (Ge a) ESN Ree | A fo 
168 | = |} —{|— |— |— | — |] — | -—!— |---| —4 —] = ]-I-I[-|-— 
175 1 }—}— | — | — | — J — | — | — | — J —)} 1 ee (i ease deos (E incon 0 oe 
160 } a Fin | ee ee fe es Pe i | e.g ae De 
Tot.| 184} 5 |27 |11| 1/44] 5 | 52/18 | 75] 1/35 (3)|18 (1)|54 (4) (5) | (5) 1.(2) | (2) 
Average |} —|— | — }— | — J— |— |— |—- I——-] — | — 1 — I-III 
weight — }— | — J — J I I I 97°3 |111°2| 100°8] — | — |— | — 
in hgr. || 26 |18-2|20-7|19-5|19 kad all — |(86-7)| (54) |(78°5)) — | — | — | — 


N.B.—Fish with spawning mark in brackets. 


TABLES. 97 
TABLE XIII. 
Salmon. Locality: Buggnes, Syd-Varanger. 
Date: Season 1909 until the beginning of July. © 
Winters 
after 2 3 4 5 
Migration 
|g | THER | mee treaconion, | Muse | giz 
2 : ¥ Birth-year. Dirthryear. Birth-ycar. Birth-year. 
°. 
% i 2/3|4]5 2| 8 a | 5 eal hs 3 | 4 
F |é Tot Tot. Tot. [——|——| Tot. 
1905| 1904] 1903} 1902 1904} 1908 | 1902 | 1901 1902} 1901 | 1900 1901] 1900 
Ly pe (NAG ila RED Fad BEAL oa Go a a RC RE “Ch ee ok | aie good Feros, eat 
14) — f— | — | — oe a I 
91} 1t}—i—| 1i—)] Pe) me me tae ee oe et ee Oe 
28| 6)}—] 2); 2}—| 4}—j; 1 Ty — 4 Payee | be 
35} 8] 1| 3] 21—| 6J—| ay GQ)y—] (@)i—| — |—|—{-j-| — 
42|10 }/—|—| 2] 1| 3] 1] 2 1 —| 4 (1)} (2) |—| (@)}J—|—| — 
491} 14/—| 3|—|—| 3}]—]| 8(2) 4 —| 7(2)f—] (2) |}—!| (2)7—]—| — 
56 | 14 |}—| 1} 1}—| 2] 1 6 (1) 4 — 11 (1)}—| — J— FP — I— | — |] oo. 
63 | 34 ||} —| 1};—| 2] 3]—]14 11 2 |27 2)} (2)|—| (4)f—|—|] — 
70 | 36 |—| 1} 1|—| 2]—j|15 {14 3 |32 1 1)}—}] (2)}—/]—|] — 
77 | 39 ||} —|—|—|—|— J — |] 14 20 (1) 3: 1387(F(1)| — J — 1)j—|—|]| — 
84 | 45 |} —|—!—|—|—] 2] 23 {14 3 142 2)) Q)|—} (i-—|—| — 
91 | 17 |}—|—!|—|—|—] 2] 8 7 — {17 Bs tng Pipe Ase | eames ERD Ae, ere 
98 | 29 |} —|—}—|—}—]J—} 11 1118 3 |27 —| (1) }1 (1(1)}—|—] — 
105 | 15 |} —|—|—|—|—]—]| 6 7 — |13 —| (1) |j— 1)}— | (1) 1 
1 6) eee | ae te oF Eee. ea) 
119} 1/—}—!—|—|—]—|.1 — |—| 1 Re see Ba Se HN eet. Mimosa Be ceo 
126} 2)]/—|—/|—/;—|—|I—| 1 1 —| 2 trea J aie Hiarya Nj ivy pyre ERY PSRRY [Tepe 
cr AMMEE fet et Go] fel art ett con Aa Cet MM eed ee Saul Mel 420) (cod 
140 2)—}—)i—!—|—F—| — |} 1 p i ee anes VA ee (Re EA) Cae Pay | ieee 
140 | 2h are be ae pee ee Pat a Bo Co Pe apf) 
154 |} — |} — | —}— | — |} — J — | — cea 1 LORE OT Laaicrsiee) CEL. Bignell | iuweey hpewee gy pmueiy Spey) Lee oe 
161.) 1 f#}—|— J — Se — fF — Te — J set VE at Ey Were 
168 1 £m ae a ee Pe a ee SE Hood REN Fe 2! 
PEG a a ices Pe ee eb oe ec ee Che pee Foe fee Fe ef ae 
Tot. |284|| 1/11] 9| 3] 24] 6 {108 (4)\98 (3)| 15 [227 (7) 8 |1 (10)| 2 [3 (18)}(2)|(3)} (6) 
Average || — | — | — | — |44°2175°7| 79°3 | 79°7 |83-1| 79-9 — |—]14274—|—]| — 
weight | —|—|—|—|—}J—| — | — |— |(467)}—]}] — |— (700) —|—]} — 
in hgr. _ —f—} — | —Jj-}] —- EAS eg eee — | (126) 
N.B.—Fish with spawning marks in brackets. 
C2. 7 


98 THE AGE AND GROWTH OF | SALMON AND TROUT. 


~ 


TABLE XIV. 
Salmon. Fosen—Senjen. June 30—July 2, 1909. 


Winters after Migration. 1 2 


Length in | Number of 
“ee Examined. 


Total. TT 


3 


Oy 
fo 
Oy 
fo 


61 


o 
BLL Ld tame | roa Seomrocer 
PELL TT TLE TL 1 orem Secon cots 
PLL LEED LLL erm axSomrocens 


pe ed eT as ce ei a 
0 i te 0) 2 a Ts 
efit tbtbeeee tT PPP brite 


ell Pdi eeee PPE tli 


SSSSRLES 


Total 


cs 
@ 
wo 
| 
ye 
ow 
| 
an 
a 


TABLES. 


TABLE XV. 
Size of Salmon (Spawning Fish). Leerdal and 
Drammen Rivers. 
Lerdal Drammen. 
a 1892-09. 1895—99. 
ee 2 Total. 3 4 Total. 
43 —_ _ — — — oe 
46 eeniupieilnnt nity — _ snstg 
49 3 1 4 1 1 2 
52 4 a 4 3 — 3 
55 7 _ 7 4 _ 4 
58 14 1 15 5 _ 5 
61 18 2 20 8 2 10 
64 21 3 | 24 7) = 7 
67 17 _— 17 4 —_— 4 
70 17 3 20 6 1 7 
73 4 5 9 4 _ 4 
76 _ 12 12 —_ 1 1 
79 5 25 30 2 3 5 
82 1 26 27 1 7 8 
85 6 29 35 3 12 15 
88 10 12 22 3 18 21 
91 10 13 23 10 9 19 
94 10 12 22 3 6 9 
97 6 9 15 5 20 25 
100 9 11 20 3 34 37 
103 4 6 10 6 20 26 
106 2 1 3 5 16 21 
109 1 1 2 5 4 9 
112 —_ — — 2 1 3 
115 1 1 2 11 1 12 
118 _ _— _— 9 — 9 
121 —_ a — Ae ts one 
124 oom _— — 1 ck 1 
127 _ — ‘ te 1 
130 — —_ — soa ae <a 
133 — _ -s — =—s ue 
SEE PSS ee Rs ee See ae Ree 
Total 169 173 | 342 112 155 | 267 


ZST‘EIPEL TSS‘ T]99S | 162| $1 |662\68T/09 G6 |OST # ISTIGITfecs|sIZitFT ae BS ZIIG6E'FOZIS6TI 66 | SF | IS |LOT| 18 | 9Z [OBT/SOT! ¢8 OFT 
rise tt 1-l—isSee asaeseeeeeee cee eecee cere —j—|—|—|—|—-|-— —_ I 
Pe et i ell Ceci ic eeecrererrecrrcritcicilice — _ 
ti—|t i-i-|-i-i- —|—|—|—J—} -—|-]-} Jn Jt ici i ci ci ic icici cic — - 
ete 1 9 lle ll lel Iai —|—|—Ft J— tt tI I Id Sit if z 
¢ |— le f—l—i—it [a lis ele dt ieee lela tc ci Ic tcc ic ic — _ 
s iz io Ili Ide ict Iie dc Ic ic Ic leicit [bit g ¢ 
ee ie¢ | izt {e |—lt I—|—i—]s |e fs [tie de [tt gs [18 J] I] OE [I ITI {EOF g ¢ 
ee | zz |oe 12 |t \t Ie |e |t fe |e |r Ie | |& Jo |% |% Jo |—j9 FL |—IT Ys |% |—]> |% |— 718 |e | ra , 
79 |oc | #2 1 |e |—Ietl6 19 J9 |S [¢ 19.1% IT Js (2 |e Is | |S Is |—|s ft It |—]% | |—[e |—/€ P II 
os | e¢ | ze I¢ lo |—le Ile |e [3 [2 JFtl6 {9 foro | Jarl 8 Js |—|s Je |& |—Is | |—]L J |2 e 9 
eet} ¢, | 09 19 |¢ |—]s |¢ |€ J8 |e |e [Ol sT\¢e Jot)? Illzti9 |9 19 |2 |# 19 19 I—I¢ |¢ |—T6 Is |F PI 6 {01 
cot| 96 | 19 12 |L |—letle |¢ Js {¢ | [St|8 9 JSTi9 |6 | Fs| IT ETISt|6 j6 Jo |2 |—Is |& |—]ar/s |F ZI 6I IL 
92z| LLI| 6b |E%|E\—]LT|IL|9 JOT/9 |b |ST|/6 |9 JeT/L |9 Jes) 13/8 9¢1z2 |b 19 |¢ It }z 1% |—]2s\9TI9 g 8% | ¢ 
goe| zie! Lb 109/09|—J9r|1|e J9OT|FI|S ]FS\ LT] L ]29|LE/ ST] 1h| Ss) s Jow| Sh) 1 fOr) OL)—) at) st |—)€z) St) 9 ¢ $8 | I 
1eF| 6g! LE |F8|F8|—]1s/S3\e JIT/OL| TL | 68) 62] OL] Se) Fe) F [29/ 09/2 6¢\9¢/e TL | I |—]2rj\ztj|—]9z|6t| 2 g OFZ 
gie| 6z| $2 199|89|—]1e/43|F | Zr/8 |% ]93|0Z|9 [Z9/T9/T Joe) FE )z 17|9¢1% 12 |% |—le |¢ |—]sSllItls ¢ 02 |— 
921 | FOL| BZ [Zz 6L/E |ST\FIIT Jo |F |S [SLi IT|S |FS/ esl T |ITj/OLjT Js |9 js pr jt |—|t |r |—yL |9 UT 9 |> ¢ |% 
06 | 1 | ee {Zr otlz |Z |¢ {% Jerid |arpe |g |% [stlorjs JF |S |% JPLIS [ste |— | JF |% |@ Je |e 1% 1 |g —\% 
cor! et | 98 [2 |t |9 [9 |& |% foals |StpIL|F |4 JL |S | JS |—/Ee JOLT [sty |T je pe |T |e prt) jor —\8 ¢ |9 
esi ez | SOT|SL|L |1r]os|—|0z]os}e |SopIl|F |L |ZtjS |OT]9 |—|9 JOw\9 | FE}FL)— | FT}OL)s | Jor|t Il 1 |6 I |91 
15%| 9¢ | GOS{9T|T |ST]8%|—|83]9s/9 |61]3s|L |9T}S |—|8 Jer} |stpse)s GZILzZ|8 |6l|zt|F |S |Zrit | It 1 |T € | 6z 
G1z| 6& | L116 |—|6 ]8s\o |Ss]oe|4 |Ss]FL|S | SL}ST|—| STAT} Tt | 91] 98/9 os}, |—|L 12 |* [8 JITI/s |8 L |sI r | FI 
oz! Le | G9T]SI|T | IT]se]/6 |6s]0s|L |eTIST|S |srjos| rt |6rpst|—| st) rE) ¢ ie |l | |zriz |¢ [2 Is Ie 1 {st 219 
gg | ez | e9 18 13 (9 TST\é SLIFLIL |L $6 |S |L FStit | PLIS |—|% i ee eee RS BP oes RE es mest Gace fia Cae & it T \¢ 
zo | 31 |e 19 |—lo | |9 12 4 1% |e |S |—|e [6 |S [4 IS [18 Js [2 19 J— || I8& |e IT Ye ET acai moaned 
a itile (mide ie eC ep ETI ICIS CISTI ITICIEIZIZIEIZ —|— 
ri—dt foci dn cit dc cdc cs cco —|—J— | — |] - - I I-III I I _— —|— 
amon! & | © frou! 3 |e fou] &| efroul 8 | Efoul S| Sproul S| L prea] S| efron] S| L frau] S PL frou) B | P prou) S| L frou] 3 $e 
“sIvok L681 968T cé6sT F68T S68l 68T T6st 068T 68ST 88st 
Hs 205 OV “pornswe AY UOUTT¥g Jo JEqUINN 
‘L681 —QSST SIv0X ‘IOATY Olls-U0vy ‘(ystg Surumedg) uowlyeg jo ezig 


‘TAX WIAVL 


Sea-Trout ( Drag-net). 


TABLE XVII. 


Locality: Trondhjem. 


June 26—29, 1909. 


0 


1 


. 8 


4 


Length in 
cm. 
Number of Fish 
Examined. 


Winters before 
Migration. 


Birth-year. 


Winters before 
Migration. 


Birth-year. 


Winters before 
Migration. 
Birth-year, 


Winters before 


Migration. 
Birth-year, 


Winters before 
Migration. 


Birth-year. 


3 |= 
B}o 


iJ) 
on 
Ree DR Ree 


22 


ef 1 SELES Leb e o Se al fasten eet ® 


oe aietebegbda le bal tae dead i dppb 
oli EL Lp ee ee ee Pe deeb se tae Ph 


22°7 28°0 


bo 
oO 


MLL tid PEEP PPR TL tl eeeb oul feel ie 


eh RPE? Ede EE bot eeee net i418 


me] | | 


0-9 


1/1°8| 2:2 


| 


3 4 


3 


ike le badsbit Pad hive bap ce ea rab 


Pees oy CUP REM ee isomer eye eee oe 
Bebe ee eee iets Pine memes Meee eee ey ie. 


BIL tild 
| 


or 
st 


3 


4 


3 
1904] 1903} 1902] 1901 


2 


Tot. 


LL LL LLL LL Lor rr nce mee mason! |] tel titi 


Jae See Bee eSe 


BeuGSke bee eae re eee eRe ee es eee Pe 


_ 
© 
So 
bo 


=] 
S 


Piel dade eed ELE Je keh iok tad bs Fg 


ed ded bb Ae a eer $f 


Bitte Pe teh Fel fetal weemtdl tet tt 
Hee Roda ks Careers Cobo roe Os cee SEED 


POSER BEN are Fa Sean eso UNS Ree HE Vee eH 


36°5|40°5 


aS 
cn 
> 
~I 


aN 
on 


38°8 


_ 


51/65) 8|— 


56 


aN 


| 


cof metoted bl Pa ie ee zea hk PS odie bd 


bo 


bo 


Sere ut ange) ome eee eewe 


i ed eee Sy et 


55°7 


14°8 


102 THE AGE AND GROWTH OF SALMON AND TROUT. 


TABLE XVIII. 


Locality : Daloselven, Ranen. 


Date: September 1—10, 1907. 


Trout (caught with fly and worm). 


6 winters, 


Tot. 


Be se 


Bad bn 


m. | um,; m, | um. 


AA EE tox 


5 winters, 


Tot. 


| Sy 


Il | 


m. | um./ m, | um, 


{99 


4 winters. 


Tot. 


pe aS 


ash 


SU. 


SE ee 


1 


m. | um./; m. | um. 


| 


Pak 


3 


3 winters. 


Tot. 


b othaddhaeiha 


Bae ee a0 


| | 
| | 
| | 
I. | 
| | 
| | 
| | 
| | 
| | 
| | 
| | 
| | 
| | 
| | 
| | 
| | 
| | 
| | 


9| —| 16} 25 


| ae eS | 


m. | Um./ m. | um, 


Tot. 


Gor (a a 


9) 21) — 


pee ht | 


Pir +l 


2 winters, 


splice, Me eae 


m. | um; m. | um. 


| 
| 
| 
| 
| 
| 
| 
ae 
| 
| 
| 
| 
| 
| 
| 
| 
| 


cB 


eS 


Lee ee So Rcdpenterd i |." 


59 


Total . 


In addition, 1 fish 33 cm. long 3 ripe, 9 winters. 


103 


Date : September 1—10, 1907. 


TABLE XIX. 


Locality: Utskarpen, Ranenfjord. 


Sea-Trout (Gill Nets and Seines). 


CCV ERP PERE OEE EPP D LP EP EE PEL LIsbfs 
BE; LITT ITEPITEETPEEEL EP ET TIPPETT TIE] 
Tea i eh ae ees eee eee Ty 
TSA ee hoe) Ree ee eee 
ea area 
E ee ss ea a ae ie 
A, PIPPITITETEEPPP PETE T EEE ttt td 
a TTI PEPPER hdd | 
BE; LILI IVTITTTEL TEI T TT TEEP Pd 
dg} FITPLITIIIIEPI TIT E TEE TTEP ttt 
Z Bes Ss eta Saad LE: 
EB] FITIIPLI TIT TTPETEPTT PTET ETT] 
pM ae lc esc) 5) RRL RR Op be pe om ata a eal 
HIRIEe es eel, 52 a Phe a a Le OL i sd 
OGL EI ee ebb bmp 
Z Re ee) cs Ss ad Be tal ES 
Bhi 8 eb ad PR] 
“A ALDAELES Solos de ae iadle A ee 
DARED) Ss cee Sead ie aU aL eae od Pa 
Amalia ie = ea Se am age ae area eee EL ae 
K igi LS 2h a Eee Gt Be 
A Reipadhets SR Weta: ee Lk Re eels ge A 
ieee ee ee ee ee ee 
MRR scucrce: clog LEA Pegs SR UES: 
AMR MS 5.) ah ha OL ie ede a hc ua Ls 
rE 
8 | gE MAFIA ONAOWOD |. 0 Set > CU es f CUS cd)r4 ws Ew | f osetia 3 
2 aa : 
W | EE | SSARRRRSRRERARERBSSSESSSIIITISTS |g 
B 


41°4 


83°3 


24°3 


Average length in cm. 


104 THE AGE AND GROWTH OF SALMON AND TROUT. 


Trout and Sea-Trout. 


TABLE 


Locality : 


Birth-Year. 


1905 


1905 


1904 


Number of Fish 
examined. 
| Os 


2 winters. 


8 winters. 


betel EEE Pb EE eA EL eckee-t 
ce] 
ois Sie a cia os AO i ee as ee Oe 


ESESSeSes FPR ER EG Reese ss AEs es 
ITIiTET TTT TEE TC REPEL E LEG Secee Bl et 
eet etre RE EP ETE PETER EET Pier ee ert 


| oy 


Qy 
| +0 
ig 
| Os 
| +0 


im cm, 


SLT TIT ITI TEL ELLE ee erurii Lite Lieens ips 


_ 


2 


bo 
— 


12°6 cm. 


%@ 
ESS) 


18 em. 


Lee PPT PETER TT it ti ri ri tir tieeeert ts 


eee el Perit el br bt) bel el eb ete bee 
EBERT ER EEST Fe USER RY PRR Ps Ss Hae pa 


eT Te eee Pet ee oe Ee il ee ee deed 


SUTTER REPS EPR Licyliat  fesmen rs! 


25 


15 cm, 


S$ 


CO 


S 


ELIT Ed PEPE Eee ee Pet Pe rbe 
PRT PCa es Gee eae couse Cobo Geeek ee kaoe 


el PE ae ee Pk pant detbal 


| 


TET EEA ES Teal Tt eee Ci Tir) eit Lert 


Piet tT EL ttt iat LL and tlre! PPP dbl 


| os 
| 40 


Ls 


Liat ttt LL) Lam ln] ccm] |al | ttt ft 


it EE GE ee tee de ees Pot tft 


aL Ae ee Lee eee 


5 


17°4 cm. 


RE a Pa bd coed ete dd tedod Pee EE EI 


28 


25°7 cm. 


o | Ebb EST Ta eed ae aE a 


5 


19°4 cm. 


Fish which have never been to the sea are printed in plain type. 
Fish which have been to the sea in italics. 


TABLES. 


105 


Date : September 2—20, 1907. 


1900 


1899 


1899 


1898 


6 winters. 


8 winters. 


8 winters. 


9 winters. 


13 


i] 
st 


ie) 


1d 


Tot. 


To 


3% 


a 


Tot. 


g 


BREBGQEEM O°) + RRB REPSES BNE ERR ERERERE 


Pill Rb peer ret PEEP EP ETE EEPTE a 
Zeer innen goatee  suNeeebuneceeauesawse 


PUPP LI E debe eee eRe ik fol paar 


reir PREP EET Eee eee) bo ee ee ea 


BESO SERPOReee nse wee ase VS See eh cses sees 
meST TTR L LETTE ti bbibi tii iii 


et Sky a, tS) Sts nk sl Soe SS 


SET Pee EIT eter tee et Cert en 


Ph BEE LR DE titted aie ba Parc ice Ebi 


Seeeeee Seeker Pees h SS Skee we res ase Sess 
PEL LELELTLELP EEL EE a Er ib ie i be 


PET ECCT PCT Rie itil ttt ae 
Pal REECE PEEP EA EBLE ED SDT tol aatrrerer aetatst 
ESSSERRUEONE SS SAAS e SSS SVARVRRe ESS ests 


PrP PPL trey ERE ere ria Tabi tl aepeem pee 
bibd dio Ee la ete ee She rept 


eo 
oo 


23 cm. 


> 


45°5 om. 


= 


re PS Ea ee ee pe eel eiteh ped cf 


= 


106 THE AGE AND GROWTH OF SALMON AND TROUT. 


Trout (fly). 


TABLE XXI. 


Locality: Aag-vand, Rdg, Nordre Helgeland. 
Date : August 12th, 1908, 


1904 


1903 


CewIHIhmwode 


8 winters. 


CRERURREPRRERSRERV SURE RR ERR | 3 
PTET EEE EL ELT TT Eder TPP E EIT 
PTET EPL EPP P ELT DT come PPE TPT 
PTET EL DeLorme PPP ET ET it 
PLETE EL Lab Troe PPT 


LLL TLL Le rcrorormcemcol | I Iii tl i ttl 


2 


Oy 
+0 
Es 


Oy 
3 
a 


2 


br AE et eT etd ed ee ad 


LL LD rommeeemccl eel IIE ii tii tidl 


LL 1 Drom meet el TPIT b ii ii el 


ate Pha p pay Pp Prerreot Lr tt rrrel 
Ssuge vets he ce ees cee Cashes ay 


1 Fish 57 cm. 
4 winters in river, 
4 winters in sea. 


— 


f-7) 


11°6 


~T 


_ 
i) 
© 
bt 
bo 


_ 
o 
bo 


_ 
bo 


to 
to 


(1) 


ae es ee 


TABLES. | 107 


TABLE XXII. 
Trout (fly). ‘Locality: Kvern-vand, Neorg. Date: July 6th, 1909. 


Birth-year. 1907 1906 1905 1904 


2 winters. 8 winters. 4 winters. 5 winters. 


| 


i) 


+ 
+0 
o 
+ 


Tot. o | 


oy 
+0 
Oy 
+0 
g 


24 16 


PETE TUT ET ET 7 tii no me E ] 
PLETE TET LT L bees ernc comes 
LTTE TT Leno coconl PEL tI 
eee eee rene ee ee ee 
dh Td ommend bate LL Lhd odode ded 
ell tteet lL Plilri ried 
ell lteelli litbrit i 


LLL tel comm et ET ddd | 
[1 FP] eeromcoal el | tt tt 


$4 LbGhe bes ceememelakht 


pe] 
° 
co 
<2) 
on 
_ 
ow 
-_ 
~ 
bo 
~I 
rary 
bn 
em 
lon) 
a 
ry 
on 
— 
ie) 
io) 
ie) 


25°6 30°3 


_— 
@Q 
® 
_ 
© 
— 
i) 
bo 
on 


108 THE AGE AND GROWTH OF SALMON AND TROUT. 
TABLE XXTIIz. 
Trout. Locality : Kvern-vand, Neerg. Date: July 6th, 1909. 
oy Be = ; arn Calculated length at formation of winter-band. 
S| P| 8 fo 8 
“| BB] 2 15 | $3 | os 
a8 e a SE 1 ist ond 8rd 4th | 5th | oth | 7th 
1 15 35 $ 2 2 50 11°0 -- — — —|— 
2 ” . g pune 2 4°0 12°1 ro a4 te eats 4 oo igest 
3 16 40 $ — 2 4:0 11°0 — — oa —}— 
4 17 50 g 3 2 4:3 13°0 —— — — —j}— 
5 3, a ” as 2 5'1 13°9 —- ao —- —j— 
ah eee ee ee eee ee a 12:6 bts oe a ae 
7 18 60 re) pales 3 3°8 10°0 14°4 —_ _— —_ | — 
8 ea 65 ” 2 2 6:3 15°5 — — — — | — 
9 $5 50 — 2 6°7 15°3 — —- — —_ | — 
10 i 60 ” — 3 3°8 8:3 14°5 — —- —}|— 
11 19 bs 3 2 67 16°2 — _ —_— —|— 
12 ais * > ie 2 54 16°5 mo — _— —_ —_ 
13 ae pe 2 en 2 5:2 16°7 oa —_ — — |— 
14 ” ” ” _ 2 46 15°2 ee = oo ie re brat 
15 ” 65 ” ae 2 6°9 16°4 = inte annie = — 
16 20 70 — 2 70 16:0 — —_ — —|— 
17 ” ” ” —_ 2 7:0 17°6 — raat =a oF iid ~_ 
18 ~ 45 rr) — 2 7-4 16°6 — —_ =a) — | = 
19 ab am ” — 2 73 17°4 — wey aoe — — 
20 i 70 g — 3 5:2 12°35 16°3 = ag | eagmele § hoeas 
21 ” ” ” se 2 5°7 149 — ey _ =, ec sing 
22 o9 9 ” _ 3 3°7 10°0 16°2 secry geri oor wee 
23 a ne ” — 3 3°8 11°0 16°7 aie gk rae: — 
24 a Hs a — 2 6:2 15°5 — —_ _ —}— 
25 rs ‘ * — 3 3°7 10°5 16°0 —- as pete) fee 
26 aa 75 99 —_— 2 4°9 16°0 — ace mae — "a 
27 21 70 3 —_— 2 6'8 17°4 — _ — —_—|— 
28 fe 80 ” —- 2 67 17°6 —_ _ — — -— 
29 - “ we hoes 3 4:0 12°0 18°5 sree aioe eee nee 
30 ” 85 ” none 2 2 17°6 — —— _— — pains 
31 e 90 =A — 2 68 17°0 — — — ah ikke: 
32 at ee 7 2 3 5°2 12°9 180 nee — Pa a 
33 As 80 g — 2 7:0 16°8 vs — pane — | 
34 be 80 ” — 3 4:2 11°5 18:2 a ms ho 
35 zo Ss vn 2 3 2°2 79 18:0 — — yt hoy 
36 = ae $ — 3 2°5 9°4 16°0 aren rae yaaa Eo 2 
37 a 85 ¥ — 2 78 17°2 — = secs pee Pca 
38 +3 9 ” 2 3 5:0 11°7 19°6 So ee SAP, Pali, 
39 22 80 $ — 2 75 186 — ior ae ested (lca 
40 ob 90 a — 3 33 10°7 19°8 air = SRT ie pee: 
41 ss 95 oe — 3 5°5 14°7 211 7, rae eae Powsag 
42 Pe oo x — 3 59 12°4 20°0 ee] — eae ete 
43 5 80 2 — 3 6°5 12°2 20°2 by ee Dit Pee 
bd + 85 4 — 4 54 9-0 12°8 20°9 ae Peres ih ot 
45 ae 90 ae — 3 3°8 11°8 20:0 —_— iad ers st 
46 i 95 ae 2 3 4°7 12°9 20°7 — ae ar = 


TABLES. 109 — 


TABLE XXIIs.—continued. 


Trout. Locality : Kvern-vand. Nzerg. Date :' July 6th, 1909. 
2 & Caletilated length at formation of winter band. 
d| 218| 48/2 
Ee 2) i 1st 2nd 8rd 4th 5th 6th 7th 
3 : 
22 100 | @ —_ 3 | 42 10°8 19:0 — — — — 
ss Pe “9 1-2 3 5:0 12°8 18°9 — a — — 
a \ 3 213 41 64 15°5 194 | — Eh ge ae 
z 33 i. be See 12°9 195 | — Aaa) (GR aR eee 
i 105.1., |. bh ieee 10°6 19-6 Sie bak abe) the hie 
23 |.100)}.8 |.— | Sf 2 12°3 20°3 = etd eae BE a ae 
; 106.1. Ree eee 16°5 21°5 he SR Ie Rig ee 
x 110 | » 3 | 3] 70 17:0 21:2 ~ Se eh oe ule 
ii Re ot Se oe 12°6 20°9 wi pened hee See beeen 
id ea 313 1 5S 164 TES tha Sere tes ad ae a va 
eh 161% 2/3475 14:8 BeBe des ceded “sho dp ons 
°° 120 ” 38—4 |. 3 5:2 14°6 21°7 ee = aa te 
24 | 130 | 3 213446 13°8 21:2 | — anes) jee Rae nal 
i 135 | » 8 | 44 50 13-0 19°77 1-976) — ) —da— 
# 145 | » 2134 365 12°5 22:7 Bias rae Bip by =e 
o 110 | 2 8 | 4] 50 14:3 208 | 233; — |—j— 
He = of aon to 13°8 230 | — ma ee oa a 
pe “9 ” 3 3 78 154 22°2 _ — —— = 
‘a fa » | 1-2] 44 48 13°9 198 | 227} — | — | — 
a 115 |., 1 bo) 3:5 3 14'8 224 | — EStpy he ay yes 
¥ 120 | ,, 313] 63 15:0 22°7 ae Lee fd ee che 
wh & » 313] 41 15:2 220 | — —_ | +, — 
af ‘3 ” 214176 16°5 21:5 | 229) — | — |} — 
” ” bd ‘aise 3 5°6 16°6 22°6 — a — — 
a3 i ” 3 | 4] 42 11:2 16-2 | 222}; — | —|— 
ne 130 | 3 21:34 72 17°4 21:8 | — Petia ae ad ii 
vo Ie a SE ee oe 15:2 22°5 | — See Se SNES Valea 
a 135 | 3 3 13 172 19°3 225 | — De Aa Pree 
96 4.1901 +» | he | eh ae 10°7 185 | 234}; — | — | — 
- 145 | » $ | 3] 56 16°5 23:2 ~_ — }—{— 
a 12200|2| — |3 1] 45 13°4 23:1 band — }—]|— 
iF 196: 1, |) b= 4S: 169 13°8 20-7 | — —}|-j{- 
ce 130 | ,, $141] 59 14°7 20°77 | 236} — | — | — 
a pe é 814447 12:5 20-7 | 240} — | — | — 
9? 9 3 2 3 1°4. 18°7 24°2 —— — . —- 
96 135 bees 2144 52 13°5 20:2 | 245) — | — | — 
* 140 | @ 814476 17°5 201 | 240} — |} — |] — 
26 126 Oh ont Se 15:3 25°1 — —_ j — | — 
a T16. his, 2141 73 12-0 177 | 24) — | — | — 
yi 140 | ¢ 3 14] 54 14°3 205 | 263! — | — | — 
pt 160 | ,, | 1-2) 4] 36 9:0 177 | 248} — | —]-— 
27 170 | » 3141] 55 15:0 204 | 265} — | — | — 
28 | 190 | 5 3 | 4160 13°3 215 | 24) — | — j= 
. 170 | 2? | 1-21 4] 55 13°4 21:3 | 270} — | — |.— 
A 200 | 3 315] 43 13°4 204 | 242] a@71|/ — | — 
29 aes 2/41] 82 18°5 243 | 276| — | —|— 
3 175.) F ft.e6 £72 9°8 19°7 | 254] 284) — | — 
30 | 245 | » 314] 75 14:0 21:3 | 270} — | — | — 
34 | 315 | » 21314 55 10°7 0-3 | 25°73 | Sher) = 


110 THE.AGE AND GROWTH OF SALMON AND TROUT. 


Trout (Fly). 


TABLE XXIII. 


: Mglnbugtelv, Agdenes. 


Date: July 4th, 1909. 


Birth-Year. 


1905 


Number 
of 


Length 
ne Fish ex- 
amined. 


in cm. 


4 winters. 


5 winters. 


Oy 


Oy 


2 Tot. 


$| 2g 


8 


ie) 


= 


O3 » 
+0 
3 


| ro | | ple ba bad roto m | esseanmeae 


PILTT EEL PEELITID ET Tecl 
PELE ELIEELULPL ULE [mec t 
LiLETITETIELILI ti tht een! 
PTT TELE ET eb rcccmel | td | 


PET ET EEL Peet romero! | | | 


PLT ETL TLL ero l aSoanl | || 


PPE E ET EP de ET EE EEL EEEI 


bikkkbkhkhbb hebhkkkbk bb! 


bbedete, CAME! Lede PLE ELT) 


pes a, oe ce ae nat ow Oy OK SW 


PL Ld beet eet PEEP Pd dd 


LTTE bee toot PPP EIT ET EET 


Et tet bb +k deed 


PetdemPEP Prt bbd dd ddd 


Total 62 


Average length 
in cm. 


Average length 
same place, 
July 9, 1908! 


a 


«3 


_ 
i) 


_ 
i] 


19°3 


17°5 
(10) 


i) 
© 


to 


_ 
wo 


22°3 


22-7 
(5) 


» 
_ 


or 


»o | tel PoP DELETE ire 


bo 
| 


28°6 


1 In fish at corresponding age. 
2 Number of individuals in brackets, 


TABLES. fe ges 


TABLE XXITIs. 
Trout. Locality : Mglnbugtelv, Agdenes. Date: July 4th, 1909. 


Calculated length at formation of winter-band. 
L. No, | Length | weight.| Sex. Setar Be rf 

1st 2nd 8rd 4th 5th 

1 13 20 $ — 1 73 —_ — — — 
2 22 = — 1 6°5 —- —- — — 
3 A 25 is — 1 79 — mo — — 
4 3 19 2 — 1 55 oe a —- — 
Se Sieg. ae 1 6°7 = a as dd 
Sea | Se | eee _— om = 
7 | 14] 27} ¢ | — |] 1 71 = a ze = 
8 rr 28 ‘ —_ 1 7°2 a mes — — 
9 “e 30 e — . 1 77 — — oe — 
10 ‘5 28 2 -— 1 73 — — — — 
11 ” 30 ” wae 1 oy; —_— _ — ands 
12 ” 30 ” es <4 ; 1 76 = freee, —_— ——. 
13 15 32 ” oe 1 671 —_ _ _ — 
14 16 42 » as 2 3°4 10°4 — = os 
15 17 46 re) — 2 4°7 13°1 = — — 
16 7 50 be — 2 5°7 12°6 —_ — oo 
17 ” 55 ” ea 2 50 12°5 pa bs case —— 
18 +5 46 2 —_ 2 43 12°4 — — — 
19 +3 50 PA —_ 2 46 12°0 — —_— ce 
20 18 52 g 2 2 4°8 13°1 — —_ oa 
21 - 55 ¥ —_ 2 66 13°5 _— — == 
22 » | 60 ey ee 2 4°7 12°7 — _ — 
23 RA 65 i 2 2 41 13°1 — — oe 
24 rr 54 g 2 2 56 13°7 — — — 
25 “ye 55 ee _ 2 60 14°0 — —_ — 
26 e 55 ” — 2 4:0 12°2 — ae aoe 
27 ” 58 ” nan 2 5°2 12°3 = al Saree 
28 na 60 ” — 2 5'8 13°0 —_ —_ _ 
29 19 58 $ —_ 2 50 14°3 — — — 
30 “a 65 ” _ 2 5°7 13°4 —— = —_ 
31 oP 70 ” —_— 2 6°5 12°4 — — — 
32 ay 70 ” 2 2 6:0 15°0 -— _ _ 
33 és 70 ” 2 2 6-0 16°0 -- — — 
34 Ar 61 2 — 2 5:0 14°2 _ — —— 
35 . 62 is — 2 5:8 15°9 — — — 
36 ” 65 ” Nae 2 6°3 15°0 on — — 
37 ” 68 ” Sag 2 4°7 13°4 er Pea mgs 
38 ” 70 ” 3 2 8-4 15'8 — bon: pees 
39 20 55 g — 2 8°3 17:0 — Sor = 
40 Pear ~ 2 73 16°9 Dis we = 
41 9 73 $4 — 2 8:0 72 — — — 
42 ae 75 2 + 2 TA 16°7 — — par 
Be hy ig PFO bem. 3 2 93 | 176 _ — - 
44 ” 75 i 2 2 6°7 18:0 mere ——; cad 
45 » | 80 ‘A a 2 7-2 16°2 sas =< — 


112 THE AGE AND GROWTH OF SALMON AND TROUT. 


TABLE XXTIIs—continued. 


Trout. Locality: Mglnbugtelv, Agdenes. Date: July 4th, 1909. 
_ Calculated length at formation of winter band. 
tee | eng wos) sox | Saet 
Ist 2nd 8rd 4th bth 
46 21 82 3 —- 2 57 16°2 — — _ 
47 “ 90 fe — 2 6°6 17°3 — — a 
48 ahs: SQ Q on 2 9:2 19°4 i = = 
49 i 75 » = 3 48 9°9 18°4 — — 
50 > 85 » 2 2 55 14°9 _- —- — 
51 23 | 110 r) — 2 81 16°7 — — “= 
52 » | 110 = 2 3 15 18-2 21:2 ~ se 
53 te 5 3 3 4°7 13°7 19°3 — “= 
54 » | 125 Q 2 2 81 179 — — oe 
55 24 | 120 $ 3 4 5°7 14:3 15°7 22°3 —_ 
56 » | 146 Q 2 2 79 21°3 — — _ 
57 25 | 160 PS 3 4 5°7 13°4 19°8 22°3 — 
58 » | 140 Q 3 4 6:2 13°2 195 | 22°9 — 
59 27 | 150 3 2 4 78 19°2 23°2 25°8 -= 
60 28 | 150 u 2 4 59 17°6 22°6 26°3 oa 
61 29 | 230 ¢ 3 5 5-4 13-0 184 25°3 27°7 
62 32 | 300 9 3 5 69 16:2 22°7 26°9 30°6 
Total . 891°3 | 727°7 | 2008 | 171°8 58°3 
Average. 63 14:9 20°1 24°5 29°2 


TABLES. . 118 


TABLE XXIV. — 
Trout.1 Locality : (Os-River 1). Tysdalsvand. Date: May 15—18, 1909. 
Birth-Year.|| 1907 1906 1905 1904 1908 1902 
5|8 2 winters. 3 winters. 4 winters. 5 winkesk, 6 winters. 7 winters. 
% ; 
58 3 x | Q {Tot} S| 2 jTot.J S | Q | Tot.f J | 2 | Tot. S | MP | Tot.} J | PM | Tot 
15) 6! 13 4] & f— Jo2) Lae i —  — I — I — J ed 
167 42] — J eee YS eee eee — ef SP ee 
PP se Be ee he ee BR Ee Bd a i tek ee Be 
BG Od Pied A ee PP Pk PE ee 
19 -O feat Loh Se ee BP PO 
20; 9 }!— | — | — | 8] 2) bE 24 2) 47— | — |—F— /— | — J — | — 
Oto | b Sad) wees st 1/2) Sh fe 
S28 ae ee fae Ql eee Dal ae petit 3 oF Tp 2 pe ae a ee 
23} 4}/}—1|— | — J— | 1} 1 pf tie] ig lt |} —)]. 1. i— ly — ti il) 
iii? Hck a | ee Be Le ee Dt | ee 
oy | ESE Pag eating (mene Cy pe eG A) fly a a ee eee fre Pe pean, Perky |e Xe 
Bios Hot Pas | P| Oe OD rk ki 
iis oie) ) ae BO es ae fot bl i oe ie 
ies oe fe) Se | Let ee Pot ig. 
Sirs tee ke | 2 Le ee a a ed ae Rf hs Po 
Tot.| 55 1 4; 6116 }12|)26) 8) 91171 3 1 4}, 2\;—] 2 1;—|{ 1 
1 Taken with fly. 


8.T. 8 


114 THE AGE AND GROWTH OF SALMON AND TROUT. 


TABLE XXYV. 


Trout.? Locality: Os-River 2. Bergstgvand, Outlet, Stor-Strommen. 
Date: May 19, 1909. 


Birth-Year. 1908 1907 1906 1905 1904 
5 ce 1 winter. 2 winters. 8 winters. 4 winters, 5 winters. 
$2| 53 ; 
a9 BE 
S | BB S|] & | Tot S | 2 | Tot. f S | S| Tot} S | 2 | Tot. J SH | P | Tot. 
Zi 
5 — — — —_ _— — —_— —_— —_— — ae SSS — — ~ 
6 — — — — — —_— — — —_ — — —_ sont bee — | = 
7 ‘iesio ones ee. aa one = — — anes _— re, | eae =i —— 
8 2 2}—{| 2) —}| —}| —7F —| —} md el et ed ed cd 
9 exe — set <a ee — -_ — ~ — =e ous ee 2=8 —_ — 
10°)-21H) A] ae pH HS] — ed ad a he a a 
11 3 1} —}] 17 1] 1) 27 —| —| —] —]—]—]-]-— | 
19} Off} —) —| +f 34.61) 9] —| —~| —f —f— f+ Fo ae 
$9; |. S00, Set Silene FO 04719] —| 1) 5b ee ee 
16) SVs) ee op rie | 1 | +) ee ee ee 
16 | Sen de) 90] 7) +1 2 Pe 
18: |) St ey a4) 4) 2) ee See a ee 
Ce Ge FS) ee RE eS ey ee ee ee ee Pee ee fe eee as) ee ee 
160); Shim) hr) Si 1 8| 8 ena at 28 
19} ot —) — eT — 1 6] teen eee ties Ss ee 
0) ehi— | — ish epee lie] 2) 1h 8d abate he 
1 | 9 —| —| —| —|—|—] 1] 2] 8] 2f 8} 6} 1}—] 12 
so) 7) — ePaper 1] 8} Sheet heir e pe 
933 | 65] —| —}| —} —}—| —] 1] —| 1) 1/—[.1] 3/—13 
a} 6} —| —| —}| —j —/—] —| —| —] 2] 1) 84—} af 2 
4 1) —]— |] —P | Se] — | | eH ae ee ee 
26 | —} —| —| —} —| —| —T —] -— | — P| —  — Fe I er 
27) — tm] moa dd cd cd cd ae a cd cd 
28} —} —| —| —] —] —| —9I —] -—| —P — I -— | — fe I ee 
29; —} —}] —] —] —-) ol od a a ad a cd -  - 
so | —| —| —| —]}] —| —!| —].—| —| —]—-|—-|-]-[-|- 
31) —f —} —t —P I) ot) ad a a ad cd Id I 
82) —f —}| — | — Pmt oe ed ao a ad nt et ed ec 
| 
Tot.| 155) 4| —!] 4] 37] 36| 73] 32| 13 | 45] 16| 8] 24] 5| 41) 9 
Average 
length in 9°5 cm. 13°9 cm. 17°7 cm. 20 cm 22°8 cm. 
cm. 


1 Taken with fine-meshed seine. 


TABLES. 115 


TABLE XXVI. 
Trout. Locality : Os-River 3. Bergstgvand, River Mouth at Sand. 
Date: May 10th, 1909. 

~ Birth-year. 1908 1907 1906 : 1905 1904 

nos 1 winter. 2 winters, 3 winters. 4 winters. 5 winters. 
gg | 823 ; 
BS | gee 
Ss | ese Tot Tot 

- Ao 8 S| Q | Tot.) Ff Q |Tot.| J 4 ot. | gS | g ot. of Q | Tot, 
WR TREE | SS RS cs Pk | a ee es ey ees ee S| 
6 1 4 ee ees | a ee 
7 3 }—}—] 8}—)}—} —F — | — | — IF — } — | I | I 
Say eee, | meee ms RH ee S| SU SS RR Oa pe ee) eee, ae 
9 2.9 2) |) pees | — | lb 
10 ee eee ee es eo Ee 0 ees pee ee eee 
3b 10: — | | ee Pees § — | ee i fe 
12 3.) -— |: oe ee | |b pe 
7.16 | —|—| eh eee 8) 2) she 
Met 44,4) — | + | — 2 ee at 2 4 ll ee ie 
eb 10°) — | — | it Spee, 1 a | ne 
11 16. | — | — ahd pies @ | 4-1 20) Ee 
27 3a — | — | i eee 4 6) Ot a 
18 1H | ri ae Pee G | 8 fh Ph me 
19) nO Wi) <b pn eee | 81 4d tet 8 4d 14d a 
20 bt |e eee et 2 ated: gh ab tT ee 
21 G With eth = beng Poe ee 2 | SES gl gt Tod 
22 6 Ue ed tee ete | — | ee! et 5 Pt de 
23 4 eee ta a pote | — | — Pe Sl a Pa et 
24. Set eed | oe a th pd eet 
25 ee ha Ee ee aed Pa aed ed od 
7 IR ET 8, SS eR Ra as cok ula) eee 9 ae ey ey bee Gas ee a 
27 Rg, WEEN ee BREE § Spe 7k aS a MS Nie Sees | aie nee ee oo aN 
26 |) Sen anh Pa eRe ee pp Poe 
9), SP a Pp ppp 
PRD fier, eS 9 REN ay | SP eS, | le 9 eee a a ee, Ce ee ee 
a ea ee RE BER oO) he et, BP OR i Oa Oe eS he 
32 Ha rem pie, arene: EMR OS AS | (me deen eee) oe Es Flee SNe see col Me Fe 
Tot 132 1|—| 5] 29 | 21 | 50] 23 | 21 | 44714) 12) 26] 4] 4] 8 
Ave 

lengt 72 13°3 16°9 21°7 24°9 

in em. 


1 Taken with fine-meshed seine. 


116 THE AGE AND GROWTH OF SALMON AND TROUT. 


Trout. 


Winters 
after 
' Migration. 


Length in em 
Number of Fish 
Examined 


Winters before 


Migration. 


Winters before 
Migration. 


Birth-year. 


aes 


zg | 
|: 

z 
g | 


Tot. 


<1 FERRER CEPEERE REE a 


ed ee ae 
LEE EEREERELELL LT eed 
PLT LELIEILIILII III ble le 
CEE EEE CELL Leer 


PITTI LEI LL ewer] | 


(eA ne ap OB kk el 


bo 
oo 
o 
=) 


| PEPE EEE Pei 


bt 
bo 


_ 
ey | TELL LLL | | pee senn} |] | | 3] 
—— 
ol Till iiittilewerprirr | Be 


a 


6 


Tot. 


ae 
LILI PILI) peo aaanwr| | 


RK Oonmoaweca- 
-—-_ 
_ 
— 


LERREEA 


PI 


| 
PRB eee eee 


owD— bo 


14 
10 
7 (1) 
3 
3 (1) 


bo bo GO OR CO 
= 
_ 
~~ 


Roded 
Pltt bd 
L 11 


~ 
bob 


NN lm 
— i 
awrrw 


30 (1)/25 (2) 


0 | llittlstetelrititit el 


58 (2 


(1) 


Prt ttt | 


rary 


— 


6 (3) 


43°5/49°9 


& 
= 


58°5 


55 


63°4 


65°8 


62 


67°5 


71°6|75°7| 69°7 


CS SS eT 
: ae 


TABLES. Wh iD 117 


XXVII. 
Date: June 25th—September 3rd, 1909. 


5 6 ; 7 8 9: ll 


bef Winters before Winters before Winters before | Winters | Winters 
sod Migration. Migration. Migration. 


Birth-year. | Birth-year. Birth-year. - ‘Birth-year. | Birth-year. | Birth-year. 


6 8 4 5 6 3 aa 5 | 6 4 5 5 4 
yn P kOks momma mara Ge: Tot. Pare |e eee Tot. F— | Tot 
1898 1899 | 1898 1899 1897 {1896 1897 | 1896 1895 1894 
ay beh) ee BOR Ao oe 
1}1 J—|}—}]—|—}—]—|-| — }-| —-}-—- | — |---| - I -  - 
—}| —}jJ-—} an | —pay—|—-|—|-| -]-—| —}-—]-|-]-|- 
ob) ay —] | —] — ep | — ee — | ee 
—|2°1—|—!|—|—|—} @—|—|-| @}—|-|-]-|-]-|- 
=| SI=1= | 0) =) = FEI=|=|=]=|=|=]=/=]=|= 
2s I} C—O ea —], — Pe ee Pe 
— | 2(1}—|2 Pa = cag) crag 0, | a a ues a eas |e 
see ee a SP). OS PN ee | ae ee eee eek ed een ee en ee 
=) PES fH ITSP le, OLE ew we) @ Gy—| — 
—{| —I—}|—}] —| —) —]—]- — I! —}—1ana—|—i—i— 
soci (Aimed 2s al Coral (nae neal ‘paak ‘ast Gane’ aa Nenad fail anal local Saal ead (i Gl 
1 |10 (4) 1 [3 (1) (4) —|8 (5) (1) —[1 (1) 2 A 4)2 (23,8) (A) Y})} 1) 
— | 77-61—| — | — | —| 841) — | —| — |—| 92-5] — | — |o3a) — | —]} — | — 


118 THE AGE AND 


GROWTH OF SALMON AND TROUT. 


kas 


TABLE 


Trout. Locality : Laagen, Lillehammer. 
“inigeation, 1 2 8 ‘ 
Winters before Winters before Winters before Winters before 
ic on. migration. migration. migration, 
: :. 3 Birth-year. Birth-year. Pirth-year. Birth-year. 
Sarl 
a1 ee TT elie 5 | 6 «lela 4 5 6 
Tot. Tot. Tot. Tot. 
1904 | 1908 | 1902 1902 | 1901 1902 | 1901 | 1900 1901 | 1900 | 1899 
7 3 21/;1;);—}] 8 f—}—]—F-—-|]—|l—l-—t a os bas 
14 }10 j—|—|3/|3],8/—|]3]}]4/—|]—|4] — — 2&8 ae 
21 | 21 |—|}—|—/|]—}6/};1/747|3 |—)]10 2 2 —_ 4 
28 |36 |—|}—|—|—f—]1]11] 9 ]138 | 8 |25] 7 i|/—j|8 
35 | 22 }—|—}'—|—}—|—]|—] 2] 6] 210] 8 3 fi—- tt 
42 | 23 |—|—|}—/}—]—|—]—]—|2]4] 6] 6 8 1 | 15 
49 |}12 |—|—}—|—]—|]—/-—]—|—!|—-I-—] 450) 2 1 8(1) 
56 1 ee eee 1 — | ee ee ee 
es | 626 —}—}— = — te | — | — | — =] — 5 2 1 «foe 
70 | 7 J}—|—|—}—|—|—|—-T-—!}-— 1-1 - Ft — | 10) 1 2(1) 
77 6° P| — | | —  — — ) — | — | — ee le ee 1 + 
84 4. f— | — | — ee | — J — | ee eh babs wel me 
91 4 )—)—] —| — 7] —| — | —J—) — } ee ed ee eee nih 
98 Bn) mee ef me ee | be a ae es iss ae 
105 2 }—|—| — | — JF — | — | — | — | — | K— | — | oe ite * ah id 
112 1 fF—|—] — | — J — fb — | — PF — | — te ed il ae bie 
119 a ee ee ee ee a ee ee ee a ae ad WSS 
Tot. | 171] 2 | 1|8 | 6] 9 | 2 | 11] 22] 24] 9 | 55 ]80(1)/25(1); 3 58 (2) 
Average . 
weightin | 9 |10 /14 11-7] 18-1] 22°5] 18-9] 25-1) 29-6] 34-3] 28-1] 36°7 | 45°3 53 | 41°9 
hektograms. 


TABLES. 


119 
XXVIIz. ; 
Date: June 25th—September 3rd, 1909. 
5 6 7 8 9 11 
Winters | Winters 
: before | before 
Winters before Winters before Winters before Winters before | migra- | migra- 
migration, migration migration. migration, tion. } tion. 
Birth-year. Birth-year. Birth-year. Birth-year. Birth- | Birth- 
year, | year. 
4 5 6 3 4 5 3 4 5 6 4 5 5 4 
——|——_|——__| Tot. Tot. |—— ——} Tot. Tot. Tot.|—| Tot. 
1900 | 1899 | 1898 1900 | 1899 | 1898 1899 1897 | 1896 1897 | 1896 hsos p1s94 
ew | 1 |2 6 Sroe bbe te REE oth Ft P| RT Bi | 
) Thy i Rated Pee sc Ek a alll Ra er FSG REO Ge Pe UE ee 
1) — {| — 1)i—); (— |} Qe} —) — Pe ede oI I Ire 
EN i 214 GY es bee (ay — | — | — J—|—I-—|— 
— |2(1) — |2(1)} — | — 1 1y— | — |} — | — |) — EK |] — I] — I I IC I 
1 —{—|1 | ee 2 23 | | ee Be I I 
rf i Ney halle Ro Sere) ag SS os Le a es SRE ee) es ee 
— j1(1)) —}1(1)} 1|—}1 2 F—}— |) —  — | e— Fe | 0 a 
—|—|+} —}J—|3 }—fs f=}—|—|— |= a —| @—-|-]-j- 
1 —j|;—/1 —|—}1—}—F-—!1|—!|—} 1)1 1 1 2. 1—- |= — 
—|—)]—|— }J—-)|;—-—)1 1 j—;—)1 );—]1 coeagll 6 Warmed scam tll (oomeell (eames | “rment (nonce 
=) ae Be iy — a || — | 
Sa Bed oo le el os ie Reet ht rant (Th (1 — | | — 
=) | los ge a a J—l—fay a) 
3(1)6(3)| 1 [10 (2y 1 (3 (1)4 (4)18 (5) (1) | — [2 (2), 1 2 (2 C2)2 (2)8. (8) 2) 2.2), @) 
— |} — | — |} 59-0} — | — | — | 81:1, — | — | — | — 1938's) — | — | 99 F—| — J] — | — 


120 THE AGE AND GROWTH OF SALMON AND TROUT. 


~ 


“YSy et} Suruedo qnoys{M peuULIE4ep xeg 1 


—|—|—|—]—|—| —| — |ove]905/o18]002\e0/oet]92] ¢ | * | “| “ | | os 4me | uz 
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—| = | = =} | | | 9-88 | 9-28 1.048 | 0-88 | ¢-8T | 0-81 10-6 19-9 | & 9 | 2 | oL-1} 99} st “Suny | 2 
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—~|™l | —-1— | — | — 1 — [0-89] 088] 9-28 | 0-821 0-21] 0-21] 9-9] $8 b | “| 09-1 | $e} St Suv | oT 
—|—|—}—]|—|—]|— | —-]¢0¢]¢2¢]¢1¢] 0.02] ¢-8t]¢6 [oo] ¢ said Hite ees re Ek 
T]he Pe bt | 1 0-6 | 8-68 1 9-98 | 0-181 0-FT 1 0-2 | OF | T 9 | 5/01] “| oT ‘3ny | ST 
—|— | ]—1l— 1 — | =] — [009] 9-2) 9-08] 082] 091] 0-11| 9-9] ¢ & | 2 | 09-1] ¢| gt Sny | oI 
—|—-}—-—]|]—|}—|—|—| — |¢2%]¢.9¢] 9.02] 9.12] ¢0tlo1r]o9 | z @ | “| 09-1] so) 9:8ny | IT. 
—|—~+ 7 1-4-1 — | — | — |9-8F] 9-54 | 9-58] 9-52 | 0-61] 0-51/0-9 | 8 b | & | omT| “| 92 Ame | OT 
Sf | el | — | — | 2-05] 0-18 | 9-62 1 0.071 O21 O87 9-2 |e ¢ | 2 | 09.1] 09] st ‘Sny | 6 
—|—|{|—|—|—]—] — | — |o2%]¢.2¢]¢-e¢]0-0¢/ 0.91/96 09] z g | “| 93.1} “| sr ‘Sny | 8 
—|—71—|—)— 1 — | — | — [9-24] 0-5 | 9-68 | 0-Z8 | 0-02 | 0-81} 9-9] 0 L “106-1| 6b} 9 *Sny | 2 
—;}—}|—|—|—|]— | — | — [9-4] 0-08 | 0-22} 0-2} 0-91]0-8 |0-% | 1 9 | 3 |9%1) “| st ‘sny | 9 
—|7] 7 1—]=—] — | — | — [9-1 0-88 | 0-92] 0.121 0.91 |0.21/ 9-0} 1 9 | 2 | S11) 8F| et‘Sny | ¢ 
— | — | = | 0-96 | 0-9F | ¢-86 | 0-0F | 0-28 | 0-92 | 9-81 | 9-FT|0-11| 9-8 [0-9 | 9-8] 0 aI | ‘| 00-1} Lh] F'Sny | + 
—1 ~~) > }—}— | — | — | — | — | 9.0] 9-92 | 0-82] 0.21] 9.11) 99] 1 ¢ | “|060/#F| F'Sny |g 
REE ee 8s 1 0-08 T O-es | 0-25 | eTT/ ed tT ¢ 96-0) “| ¥'Sny |Z 
—|}—-}7-}—-}-}]—!]—)!}—|]—] — 1o8¢! 022] ¢-9t!] 0-6 | o¢ I ¥ 3 | 08-0| $b] @T “Sny | T 
UIST | UT | WIS | WIZE | WHI | MOL] 6 ms Wu 199 WI Uy pag pug | 481 
"yyAoD | *yIA0IH “18y i - 
pele}1V | Pelezly ‘xeg| ul ‘aqeq . 
SUV | ee quem! 5 3 
“pueq-10401M JO UOYwULIOT 4e YISUeT pozens[so SIOQUTM | SIOPUTA g s 
"6061 ‘g tequioqdog—gziounr : oyeq7 ‘IoUIUIBYETIVT ‘ueseery : AyTeoory 1ynory, 


VOTTAXX WIV 


121 


TABLES. 


_ — | — | — | — | = [0-09 | 0-F¢ | 9-9F | 0-88 | ¢-08 | ¢-81| 0-01 10-9 || F b & | o%-%| “| gt ‘sny 
— — |— | — | — | — |0.09| 0-¢¢ | ¢-8% | 0-98 | ¢-€2 | ¢-8T | O-TT | 0-9 F P 2 | 09-31 29| et Suny 
— —|—{1— |— | — | — |0-6¢ | 0.8% | ¢-88 | 0-2 | ¢-1z | $-9T | 9-8 g $ “1 01-2] “| 92 4tme 
— — | — | — | — | — | 0-69 | 0-44 | 0-08 | 0-44 | 9-61 | 0-9T | 0-11} 0-9 |} @ Ba 8 pets (ae) aay 
— — |— |— | — | — | 0.09] ¢-T¢ | ¢-2F | ¢-28 | 0-92 | ¢-0% | 0-ST | ¢-2, PF P “ | 99.2 og 4g 
— —|—|— | — | — | — [0.09 | 9-8F | 0-98 | 0-92 | 0-6T | 0-ZT | 9-2 g P “| 39-3 | “ | Tr 4me 
— — |— | — | — | — [8.62] 0.6% | 0-LE | 0-8 | 0-22 | 8-91 | O-ZT | O-L g ¢ ei ae ey 
— —|—}— |— | — | — | &-6¢| ¢-FF | 0-68 | 0-12 | 0-91 | 0-8. | 0-F g F “jy ee 1 1 ot Ame 
— —|—|— | — | — | ¢-6¢] ¢.¢¢ | 0.9% | 0-421 0-12 | 0-91} 0-011 ¢-4 || § ¢ “1 09-3} “ | ot ony 
— —}!—|—|]—|— }] — |0-6¢) ¢-8F | 0-98 | 0-22 | ¢-61 | 9-31 | 0-9 g F ei ok Oe ree 
— — | — | — | — | — |$-6¢} 0-19 | 0-14 | 0-88 | 0-92 | 0-8T | 0-31} 0-9 | # bo) Sy) 8 YS | 9s 4m 
-- — | — | — | — | 0-09] ¢-T¢ | 0-8F | 9-62 | 0-82} ¢-LT 10-81 }0-6 | 0-2 g 9 ep we |) gp sny 
— —|+— |] — | — | — | 0-09 | 0-Te | 0-24 | 0-38 | 0-¢% | 0-8T | 0-ZT | 0-9 $ g * 10¢-3| “ | g ‘Sny 
= —}|—|—|]— | — |] — |9-6¢ | 0-9F | 0-98 | 0-62 | 0-81 | ¢-0T | ¢-¢ g P “)0e-¢|19| zg ‘sny 
— — | — | — | — | — [0-89 | 9-24 | o-28 | 0-48 | 0-02 | 0-FT | 0-0T | 0-9 | go} “10% |“) 13 de 
_ —|—|—|— | — | — | $89] 0-24 | 0-¢8 | 0.52 | 0-61} 0-8T | 9-9 || 8 b | “| 09-6) ‘| ot Sny 
— — | — | — | — | ¢-8¢ | ¢-LF | 0-88 | 0-L2 | 0-22 | O-LT | 9-21 | 0-0T | 0-¢ g 9 | SSB | 6 ‘ydeg 
— —}|—|—]|]— | — | 8-29] 0-89 | 0-¢F | 0-98 | 0-12 | O-LT | O-8T | 0-9 F F “109-8 | * 9 ‘sny 
-— — |— |— | — | — | 9-89 | 0-6F | 2-68 | 0-92 | $-12 | ¢-LT | 0-0T | -¢ § Gg fe Big oe Ame 
— —|—}]—|— | — | — |08¢| 0¢F | 0.48 | 2-221} 0-81/0-TL|/ 9-7 | $ $ “1 op. | | gcsny 
— —|—|— | — |.— | ¢-¢ | ¢-8F | 0-48 | 0-22 | 0-02 | ¢-FT 19-6 | ¢-2 § ¢ “| SL-% | 09 p Sny 
— —|— | — | — | — |&-F9 | 0-14 | 0-8 | 0-82 | 0-81 | 0-111 9-2 | 0-4 $ g “ }09-4| “ | eT ‘sny 
— —|— |— | — | — | 2:99} 0-9F | ¢-FE | 0-22 | 0-02 | ¢-ST | 0-0T | ¢-¢ $ ¢ * 109.2] “| gl ‘sny 
— — |— | —|— | — | — | O-Lg | 0-6F | 0-88 | 9-92 | 0-08 | 9-ST | 9:9 $ $ 3 | 08.2} “ | 9g Ame 
— —|— | — |] — | — | OL | ¢-8F | O-TF | 0-38 | 0-12 | 0-FL | 0-01 | ¢-F || F P 2) “ |6¢| et ‘Snuy 
a —|—|—|— | — ! — |o¢¢ | ¢.0F | 9.62 | 2.4% 0-02} ¢-0T 0-2 || 2 g “10z-3| “| 6‘sny 
ae —}—|]—|—]— | — |¢.9¢/ ¢.8F | 0.1F | ¢.62 10-64) ¢-eT 19-2 || b “| ¢1-3| 8¢} og 4p 
= —{|—|—|— | — | — |¢-4¢]| 09% | o9¢ | 9-22) ¢-6T 9-211 ¢-9 || & ’ | $}98-1| “| o¢ 4mm 
_ —|—|—|1—]— | — |0-4¢ | 0-0F | 0-62 | 0-82 | ¢-9T | 0-0T | 0-¢ z g 2164-2) 1¢| el ‘Sny 
Let W3ZL | UIE | WOL 76 18 14, 79 wg wy pag pug 481 y 

z "WYMOID | ‘TAMoIp 13 Q = 

PETTY | POV Juxog| ur | & 9 x 

I0yv o.l1OjogT 8 S10 on ea 2 

“puedq-19qUTM JO UOPwuLIOT 4% YIZuE'T poyefno[eD STOFUEAL | S1O$TTM gayi: eg 4 

"6061 ‘g Tequieydeg—gz ounr : oye(T ‘IOMUIBYETIT ‘ueseery : Azpwoory *ynory, 


“penuyjuoo— OTTAXX WICViL 


(Eon Se Pine Se 


Gaewuiee 

bia Lee 
Tod lled 
$3e3s !3333 
SeIAXLARLR 


» 
o} 
ie) 
> 
Noy 


> 
OP SSBOSLSLOLS 


SS 


cs 
aN 
© 
aS 
Ys 


~SOeS 
SSES33 


> 
Bry 
© 


o & Ss 
laaa 
OOO 


?? 
aN 
oo 


> 
— 
© 
Po) 
© 


WDA 


CLOVE SER MER eee eer he et 
Pada egead )d edaeeee 
al dda ei 
Pose eee eee oe eae eae 


oka 

ISse 
SS 

(Skee 
HCO 


0-3T 
0-9T 
0-31 
¢-§T 
¢-F1 
0-§T 
0-0T 
0-TT 
G-ZI 
0-01 
¢-6 

0-6 

G-FI 
0-8 

GET 
0-0T 
0-0T 
0-0T 
¢-9 

0-TT 
0-61 
0-31 
0-1T 
0-31 
GBI 
0-31 
0-31 
¢-TT 
0-31 


2SO8SSS"2S99SS9 
ett OOO Orr Ory 


OD SH OD MD HOD 0D 09 0D 03 09 03 OD SH OD SH OD OD 09 1D HOOD SH HH OD OD SH eH oH 


WOOGCWOAPAAOHOAPOH GH GH OSCHWHAH OCHWOWO AHH odd 


bce 


puz 


“puLg-10,UTM JO UONeULIOT 4e YSU pozelns[eD 


S109UTM 


“qyMoID 
per0y1V 
a10jyog 

SI9}U1M 


‘oyeq 


*606T ‘g oquieydeg—gz ounr : e487 


122 THE AGE AND GROWTH OF SALMON AND TROUT. 


‘IoMUIBYeT[V] ‘aeseey : Ay]woorT 
‘penusjuoo— OTT AXX WIAVL 


*ON-"I 


TABLE XXVII0.—continued. 


Locality : Laagen, Lillehammer. 


Date: June 26—September 3, 1909. 


Trout. 


TABLES. | 128 


PRPERE ROPER TELE ERED REID ED ES 


14th | 15th 


PREVPEPOPPEEPP EEE REE RIL PPP EEU 


13th 


PEEVERREPPI TERT EREET IEG ae 


12th 


Bee ieek Ree eee ee 


lith 


LIETLEEIS PETE PE ELECT Ett 


10th 


> > 
TITLED Pes PLibltibitititttttdd 


9th 


Se Thea teRPERLE NV YSSSZEIS Oe Og: Bee = 
oo SS '3S SS8S 6'SSS3'!2R 


8th 


THQODHORAEE OK OHDAADSHHDHRHEANDH OH 
DSSSSSSASSOOS SS OBO SSS SOOESOSE OS 


7th 


OHH SRR DRSOESSOSSHATADEAHDBSOUS 


6th 


DOODHALOHSHE 


rDNOANAHHOADHAD 


Calculated Length at Formation of Winter-band. 


5th 


OOH HOON OW 
od MWoononoos 


ROWOoOrd rr DOOrDHN 
DADHAAIC CON 


0/2 
0) 3 
5 


BOoOAOSCDaon 


4th 


De 
DOAN DCO AN CON i OD 
oP 


0 | 27 
5 | 37 


7) oe ea) eee! On Ot awe one. © 6. £5 o. &- £6. & Fs is Se & OO: @ ane 


WAAC HH HO CO OD 
ANNANNN TAN 


5 
5 
5 
0 
22°0 
5 
0 
0 
0 


8rd 


0 
0 
0 
5 
0 
0 
5 
5 
a) 
0 | 21°0 | 25 


cae Sa 6. Cy Cn Cs On ee eee oe «hh UO Sh! Et Orr ew ee) oe Se es oe, ee Oe 


Srotwdoronno 
CS ee ee ee 


7 
19 


2nd 


aoe Se Oe Cs ee ee en or en eM ee” Oe Oe Oy, oe Oo” 6 la ee OS ake 


ist 


After 
Altered 


HH oOMOMOPMPAPOMAA ADAM OM dA HOW OW OM HH 


Winters | Winters 


Before 
Growth. | Growth. 


Altered 


MD WD XD WD OD CO HOOD HH HH 0 19 19 109 10H HO OH DOH OD 


Sex. 


SOAR ER a RR we Oe Se HH HR & SG Aa KR A A 
ee ed 


Weight 
in 
Kgr 


> 
7 
5 
7 
0 
1 
6 
6 
7 
0 
3 
5 
9 
0 
3? 
1 
4°25 
4°35 
4°50 
4°00 
” 
4:15 
4°60 
4°50 


“UD Ul Y4SueryT | 


” 
9 


> 
, 
’ 
, 
? 
’ 
’ 
70 
b 
’ 
’ 
> 
? 
> 
? 
’ 
” 
” 
” 


£ 
© 


30 | |. 
13 | 68 


a ae eS 


July 26 | 72 | 4-05 


July 19 
Aug. 4 

Aug. 12 
July 15 
July 29 
Aug. 12 
July 14 


“ON-'T 


86 | Aug. 13 | 67 | 350 


95 | July 11 
96 | Aug. 12 
103 | July 14 
104 | July 28 
105 | Aug. 4 

109 | July 19 
110 | Aug. 12 
111 | July 13 
112 | July 22 
114 | July 15 


Aug 
Aug 

91 | Aug 

92 | Aug. 

93 | July 18 


88 | Aug 


87 
89 
90 
94 
101 
102 
106 
107 
108 
113 


x 
i~ 


> 


eo 
oD MD 
rE 


| ad 
Pr) 


= 

oo 

= 

oD 

Na) 
Peeees 


les 
Pee | 
SSSSSs3 'S3es 


CIC 


RGEC ae 
ERA oe ee 
Re ce ee ec ee eae at ee 


SSSESS 


PT TTT ee PRP Bae Aa 
Re a Oe DY 
OD HH tH Hct HD eH Ht 0 0 Hs ed' 1 10s T' © 
WOOHWOP OO AMO OG OHO HO AMO dHWO HH Hw HOMO 


PSLOLES OHO oYY 
SSSeseoe ,oveoce 
RHwosooo1S5555m 


oS 
~ 


a 
3 
é 
2 
8 
3 


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“oye 


“TOMIUIBYST IV] ‘ueseery : Ayrpwoory 
“panuyzuoo—"OTTAXX WIAVL 


"6061 ‘g tequieydeg—gz ounr : oyuqq 


124 THE AGE AND GROWTH OF SALMON AND TROUT. 


ONT 


TABLE XXVII0,—continued. 


Date: June 26—September 3, 1909. . 


Locality : Laagen, Lillehammer. 


Trout. 


TABLES. | 1250 


° 
3 LR oneneee bat bee P Rae ERP Be 
oOo 
2 POE ek or eto Ee PPE PET RS 
o 
a ° 2S) Soe 
& MITE ITTPI TIT PIITll gti lgel lose 
” opooonuco 
¥ 2,1) ,eneoveos 
& 9 HA oe an 4S Dg DANS 4 
; a |e > ww bell Eg 2 PEELS SO 
gq |e] ellilligtttsllslellalligsgeaas 
&§ | 4 221; SISSSES 1 ISLES IL  e2ee2e2 
~~ 
z Ha ay ad w2'LSSSF' 'S2S2RE'S RRS SSae 
S g | Seeeeesesses ;eoseere)) eeesess 
g & | SSESSLSRrleek 'SXaktsexk SSHDDOEL 
E SP LSSSSSSSSS | HP SSlsSe) | | Soesece 
rs | SSSSYSSSRSLS'ESLSLSES SSSERNS 
~ a | SSOBeee teeter jeccee est 1 iseeeeee 
$ |2| gezgssesesse | seaaces! | lagessss 
: a) Se SSeS eeer ee Pesce ee 1 Sees sex 
3 @ | SHTSSSSSSSSSS | AGASIST ASSSSSs 
| es ee SP SSSSSSBRSS | SSSSSES | |  SSPSSSe 
oS 6S | HRBSRANDAROSA | HABNADS AaRSSSss 
4| BECS2e Sesser coreecr 4 Ss lessue 
* | SRRSQnRSRRRat 'ARRRRSS MAAN 
we | SESCSSSSSSLS , SSSSYO ~mOSSOKO” 
& | seenaeaeagas laeaseee! | laxguacr 
g | Secceeesece™s )2eceoee SonoooN 
&) -ngesessaues lanessas | | loguaway 
» | SSSSSSSLYSSSY ;SOSSOONNO HHS SHO 
2 DOM OOORKHOOCS lSHODOOE | | l Homo ay 
a 32 
zee OWHHHHDOMDODOONHODOHODROrKDOOKROOH 
ond Sal 
E~g8 
eSBs 
£255 DDO W MOH OO HHH OHWOH HOMO HHH ODdO HID WH 
Ea SE 
3 O+ 2tO 204 2400+ 4004+ 40 SOF 240 OF F4H00HHO FE EER ARRE EE 
-_ 
$28 | S8882SRZ RSSSSRQSSSSSSES8s -AZEZs 
= = Orrer~rro DWODDROBr~OOrmODrEr DOOD Qamiae 
‘mourmaueT | oS 7S TH RH 2H 7H 22 2H 2 2BSR 22°28 *SSSES 
| tb+3. bh 8 dh 8045. b> bp bb b> bh bb bb bb bb to a bss bab abe eH ches 
A BSogss Singsasgsasnyq -<- 8-8-0 8 
Pe ch ie ee cea e ei ee 
‘ONT SRGRSASSESSSSSOSSSSSSSESSSSSLERR 
Se Os ne Oe Oe ee ee Oe ee BB Be Be Be | 


126 THE AGE AND GROWTH OF SALMON AND TROUT. 


TABLE XXVIII. 


che oe i 


Trout.1 Locality : Laagen, between Langesjgen and Hglen (Numedal). 
Date: August 26—27, 1909. 
i= : 

4 a 3 ef Calculated length at formation of Winter-band. 

. | 88) 8 | ges 

- 8 e e 1st 2nd | 8rd 4th 5th 6th 7th 8th 

1 19 = 4 + 3°5 76 | 116 | 158 -— — — — 

2 20 —- $ 4 34 8-3 | 12°6 | 16°6 — — — — 

3 24 — ” 5 42 78 13°4 | 17°5 | 21°00 — — —_ 

4 26 os 2 6 4°3 74 |11°0 | 14°99 | 19°5 | 23°5 — —_ 

5 | 2 |— | , | 6449 | 88 | 124 ]175 | 222 | o3} — | — 

6 29 — i rj 4°7 88 |.11-°2 | 15°7 | 19°0 | 20°7 | 27:0 — 

7 34 — by 8 50 |10°6 | 18°8 | 17°8 | 21:0 | 24-4 | 26-4 | 30°5 
Average lengthinem. .. .]| 43 8-5 | 12°3 | 16°5 | 20°5 | 23:3 | 26-7 | 30°5 

TABLE XXIX. 

Trout. Locality : Laagen below Hglen (Numedal.) Date: August 23, 1909. 

3 Fi ; 2 F 5 £ Calculated length at formation of Winter-band. 

4 gs | & 42 A at | na | ora | am | ce ] om | rth | oem 

1} 21) — | @ |] & | 42] 79 1128 [153 }176] — | — | — 

2 23 — $ 5 3°4 73 | 12°0 | 15°4 | 19°4 oa — — 

3 25 — ay 5 4:3 9°0 | 14°8 | 1871 | 21°4 _- — — 

4 26 —- ¥5 5 59 |10°9 | 17°5 | 20°4 | 24°0 aa — — 

e. | = | 9 bbe) 47 [106 | 104 | 107 | 984] + glee | tS 

6 28 — $ 5 58 |10°0 | 16-2 | 19°5 | 23°7 — — — 

7 29 -- g 6 4°7 9:0 | 12°99 | 17°6 | 20°4 | 25°9 — — 

8 30 — $ 8 5°6 9-8 | 12°0 | 15°4 | 19°3 | 20°4 | 25°4 | 28:3 
Average lengthin cm. . . .| 48 | 9°3 | 14-2 | 17-8 | 21°2 | 23-2 | 25-4 | 28:3 


1 Taken with worm and fly. 


127 


“Ay pus “qreq Suruurds ‘uo YA WOABY, 1 


TABLES. 


6-Lb | GOP | &-ZBb | $-6E | L-CS | O-FE | LOE | §-LG | 6ES | 0-03 | 3-9T | 8-BI | 3-6 €-¢ “UID Ul YSUS] OSBIOAY 
6-LE | Z-9F | & BP | §-6E | 9-C8 | 9-68 | L6G | §L13 | 6-ES | 2-61 | O-FL | 66 b-L GF tL “ | 00¢e‘T | 6% 0% 
— — ae — — 8-88 | ZFS | 6-66 | G96 | 9-13 | OLLI | 9-ST | 2-6 LF 6 2 o¢L oP 61 
Sars = <> tz L-9& | 0-F§ | L-08 | LZ | 2-86 | 6-06 | 9-L1T | FL | 0-01 8-¢ or $ o¢¢ 8I 
— = a a — | §-bE | ZTE | 1-83 | 68S | 66T | 8-9L | BET | 8-6 0-9 6 ** | 009 6E LT 
— — SD he — OS | $38 | F-6G | F-9Z | 1:02 | 8-9L | §FL | 1-6 G-e 6 "4 00¢ 8§ 9T 
a — = << e¥ On Z-F8 | 1-18 | 6LS | 28S | L-6T | 8-9L | &-FL | 8-0OT 0-¢ 6 $ CLF LE GI 
paged — — = 8-FE | 83S | 1-08 | 8S | 6S | 9-1 | 6ST | $l | TOT 9-¢ OL “| oge dg FL 
=< me ae is oe “a = 8-SS | 8-08 | Fes | 9-03 | GOT | ISL | 0-8 G9 8 “| Oth 9¢ €T 
= oe — i > =~ 8-TS | T-6% | 0-93 | 6:03 | ¢-9T | 6-3. | §-0T 9-¢ 8 4 00F sii SL 
= a ae as — agit L-08 | F932 | 0-8% | 9-61 | T-LT | 9-8 |-6-01 0-9 8 «| o¢s ce IT 
ae — —= se tee — | 0-08 | 1-23 | 1:33 | FSI | LL | FIT | 68 L-F 8 & | OSF is Or 
a _ ——— = — nm GIS | 6LG | &FS | 1-02 T-@L | 0-3T | 2-8 LP 8 es o¢s FE 6 
—- = a 23 ae sans T-08 | #12 | OFZ | $-0Z | SLI | BST | SIT | FL 6-P 6 a sf te 8 
=? = — — a ee C-08 | $16 | 8-86 | &-6L | 2ST | 0-31 | F-6 Fe 8 “| OOF * L 
= = eed ee ra — 9-08 | BLS | BS | 1-61 | O-CT | BIT | $8 6-F 8 sh} €¢ 9 
— mes ae — — ee G-8S | &-osS | 1-86 | 6-61 | GOL | 9-6T | LOL 9.9 8 | o¢s ie c 
—_ a — = a == €-82 -| #&S | 0-66 | T-6T | 0-91 | BSI | 0-0F 6-¢ 8 $ ? és P 
— = —s > —e aed #62 | $96 | 9-86 | 2-03 | 8-ET | EL | 6-6 6-¢ 8 g 008 && g 
— — ae 44 ee => — |.1-93 | 683 | 8-06 | GGT | ¢-TT | 6-2 8-€ L $ = 8Z a 
~ge = — Ear: = — = = — | 31% | 1-81 | 68 | 2-8 0-¢ ¢ Q | 22% ¥ I 
wer | user | mer | wit | wor 116 m8 m9, 199 139 beh pig pug 481 
*"s10qULA "xog “13 UL | ‘UID UT ON-"T 
ur easy FYSIOM | USUET 
“puvq-1o,UIM JO MOWWeULIO,T 48 YASUE] poyeno[eD 
"6061 ‘8Z—FZ JSNSNY :07eq ‘(Tepounyy) ueTsx : Ag1TwoorT 1qnody, 


‘XXX WIAVL 


128 THE AGE AND GROWTH OF ‘SALMON AND TROUT. 


TABLE XXXTI. 
Trout.* Locality : Djupe (Numedal), © ‘Date: August 24, 1909. 
£ 
i é - g. 2 Calculated Length at Formation of Winter-band. 
“| a | & [s= |88| = 
% e 
: £ oa & 1st | 2nd | 8rd | 4th | 5th | 6th | 7th | sth | 9th | 10th 
1} 24|]—| a |—] 5] 67 |-11°9| 14:8| 18-7] 216) — | — | —~ | — | — 
2/26|—{|92| 4| 7] 52] 7:8) 11:3] 160} 18-5} 21:2| 23-9) — — — 
3|30}/—| & |—| 61 50 | 10°7| 15:6] 18-2] 22-0] 275) — | — | — | — 
41, |—I,, |—! 7} 79 | 18°5| 16°7| 19°7| 24-2] 26-3) 28:2| — — —_ 
5|37|—| 21 5] 8 || 386] 8-7] 13-6] 21-7| 26-4] 29-4] 32°0| 35-7) — | — 
6} 38|—| 3s} 4] 8 | 48] 83] 11-4] 17:2] 21°3| 26:8) 32:4] 35°7) — — 
71,, |400| 9 | 4] 8} 42] 88] 13°6] 17-9] 22°7| 27-2] 31°7| 36-7) — — 
8|40|—J] ,, | 5] 10?]| 58 | 11°6| 17:7] 20°3| 25°5 | 28-8 | 31:2 | 34°6| 36-7 | 38°4 
9 | 42 |620) ,, | 4] 10 |} 65] 96] 14:3] 17°8] 211 | 30°2 | 34°2| 36:3) 39°5| 41°0 
Average length in cm. || 5°4 | 10-1| 14:3| 18°6| 226 | 27-2] 30°5 | 35°8| 38-1 | 39-7 
1 Taken with fly. 
TABLE XXXII. 
Trout. Locality: Ossjgen. Dagalid (Numedal). Date: September 7—8, 1909. 
6 é b § Calculated Length at Formation of Winter-band. 
4) 21 8 |sex| & 
A e g 
: 5 g Ist | 2nd | srd | 4th | 5th | 6th | 7th |’ Sth | 9th { 10th | 11th | 12th 
1 | 51/1200| 2 | 9 |} 7-4] 11°4| 14°8| 19-0 | 24°7 | 31°5 | 38°7 | 44-2} 49°00; — | — | — 
2 | 53/1380} 9 | 9 || 7:0} 11:2] 15-5 | 21:9 | 27°6 | 31°6 | 38°0 | 44°7 | 50°2) — | — | — 
3 | 54/1700} 2 | 9 || 5:3) 11-0} 15-4 | 18°8 | 24-0 | 31°5 | 37-7 | 44-3 | 50°38); — | — | — 
4 | 60/2000} ,, | 12 || 85 | 11°2| 17°3 | 22-2 | 26-2 | 31-0 | 36-0 | 42°4 47°7 | 53°0 | 57°0 | 59:0 
5 | 62 | 2130 10 || 9°0 | 12°5| 16°8 | 21°3 | 28-2 | 36°3 | 41°5 | 49°5 | 56°5 | 60°0} — | — 
6 | 63 | 2570} ,, | 12 || 7:0} 11°0| 16°5 | 22-0 | 27-5 | 35°5 | 40°0 | 48-5 | 53-7 | 57-0 | 59-0 | 61°4 
Average length in em. || 7°4 | 11°4| 161 | 20°9 | 26:3 | 32°9 | 38°7 | 45°6 | 51:2 | 56-7 | 58-0 | 60-2 


1 Taken with spinner and fly. 


TABLES. 129 


TABLE XXXII. 


Trout. Locality : Krokaa, Skilbotten, Brgnngy. Date, July 21, 1907. 
Birth-year, 1905 1904 190 3 1902 1901 
Length, | Number 2 winters. 8 winters. 4 winters. 5 winters, 6 winters, 
in of fish - 

cm. examined} ~ | © |Tot.] g | Q | Tot) S| @ | Tot.| S| S | Tot. S| G | Tot 
12 1 Pay Pe ae os foe Ped Py ae Pa af Be 
13 2 1|— 1 1|— Pe 95 oa ee eee eS ee 
14 2 —|—|--|—| 2 Pia pas Ps fos Pee f SP Spe 
15 3 —|—|;—I—| 2 2,— 1 Gh a ee a ip ear ee 
16 6 —|—|— 1|— 1 3 2 Beh ee Tree Sy ae 
17 14 —|—|—yJ—;—!—] 5 3 8 2 4); 6}—|]—]— 
18 eS eee eee Fee ee eee OE ee oe Bee eee 
19 8 f[—{|—j}—F—] —| —F—]} 1) 17 4] 2) 6@Fy—]-14 1 
20 13 —|— | — FS} OI 1 | — 1 11.3 | 10 1 | 2 
21 4 — | — | — JF — eS BK I D) 2 re peed eee: 2a 
22 5 — | — | — Fy — | eI rd I I 2|— 2 3} — 3 
73 1 — ee | | Fh ] eS |] KT 1 Ke 
24 Se eee ee eee a ee ee, ee, ee ee Cee een 
Total 79 2)}—) 2] 21:41 67131) 10! 287238118141] 5) 21 7 

Average 
length in cm. 12°5 14°5 17:2 18-0 21°0 


1 Taken wlth fly. 


8.T. 9 


1830 THE AGE AND GROWTH OF SALMON AND TROUT. 


Trout. 


TABLE XXXIIIz. 
Locality : Krokaa, Skilbotten, Bronngy. 


Date, August 8, 1907. 


Birth-year. 


1905 


1904 


Number 
of fish 
examined. 


8 winters. 


5 winters. 


 % 


g 


Tot. 


Oy 


be} 
aa 


ie) 


| RS Ror WOOQwWNWwwrr 


Phd dd b bed dd 


Pid EEE L EEE Lee 
LJ ttt bt beta. 


PLT ELLE L Peel I 
PTET ET Peete tI 


Beeeeer se 


bl elioetetiie 


| chews weed dot) 


Se Bes everecyen | | | | 


I teoml tell ti tl 


Lb ett t Pd bl 


b bcomt mol ttt Lt 


letolllIltit 


Be sey See mca 


Leteolti tli ttt 


Total 


31 


Average 
length in cm. 


—" 


bo 


i) 


12°3 


i) 


rs 


14:0 


a] 


3 


8/11 


17°2 


» 


i] 


19°3 


~T 


1a) 


20°7 


1 Taken with fly. 


a 


Trout.! 


TABLES. 


TABLE XXXTV. 
Locality : Sannavand near Harstad. 


131 


Date: August 3, 1909. 


1908 1907 


#5 
7 


1906 


1905 


1904 


1903 


190 17 


1900 


1899 


1898 


1 2 
winter. | winters. 


5 
winters. 


9 
winters. 


winters, 


10 


il 


winters. 


Length 
Number of fish} = 
examined. 3 


3 | \Tot.Ad | 2 |Tot. 


Io | 2 lrot.d S| & | Tot. 


| 


A 3 2 Tot. 


g 


pe Ee 
| 


a 
Oo 
| bo e PCO 


ro | 19 | 
ao 


bo 
~T 
_ 


Dwr e pre | — 
| Bot et es ee | ne 


bo 
4 
CRO DDTROAO ROO 


ao 
ray 
_ 


2 Tot. 


| 
| 


all a, ed 


= 
| 


| 


a ee OO OO Oe 


% 
rete | er] oe | | me | meno ms conver 


PTET TTT TT Tp] f | een mame | | | | | | | | | 


SSSSeeeer seer Ate eer eer ee. vere S 


| 
| 
pepebed dd tih hi bt bid dt Pt Pere Peet PPE 


Plesk ddd bide er io Bil Bag ied | 


in cm. 13°9 15°5 


20°6 


15) 9) 24 


24°6 


'22)17| 39 


28°4 


12)10/-22 


32°2 


34°6 


40°5 


bo 
ay 
| 


46 


47 


49 


1 Taken with fly, spinner, long line. 


132 THE AGE AND GROWTH OF SALMON AND TROUT. 


TABLE XXXTIVs. 
Trout. Locality: Sannavand near Harstad. Date : August 3, 1909. 


he B § Calculated Length at Formation of Wintereband, 
be 4 . Sex. 3 = 
3/8] $ ao] & 

S| é & || ast | na | sea | atm | stm | oth | rem | stn | oem | aotn | rath 
1/138; 20;3}] — 1 oe 1 |] — ) ae ee ee ee ee no 
2 ” ” ” See tey 1 6:0 _ —_ se —— — pes = Awe ee pe De 
3/5, ” g rr] 1 75| — -- —- — —_ mie am == 4 at ES 
4/14] 25}3| — tilene ) — | 7 eee ee 
‘5 ” ” ” Lym 1 8:0; — ame — _ — _— oul Seal a, Fe 
6|,, ” ” = 2 6°6| 10-4) — — — inte eek ae pei poe = 
Is) 2212, — 1 le SR a) ee | is ey Be: tea) |e ems 22 = 
8115] 30/4] — Sil aal-e4) — | — | eC eee ae 
9/16] 40/,,| — Sines es | — | — ) 22 Pee eee 

” 35 2 — 2 60; 13°66; — —_ _ — — — — —_— — 

17; 40/3] — oh wariso| — | —.1 [ck 1 yA he ee 

19; 50/2; — 3 7h 20'S 1148 | —. | el ie, be, Lee eee ee 22 

20; 70;3)] — 3 e181 12°90 bl ae ee ee ee eee 2% 

” 75 ” ha 3 3°4 70 12°9 = — 803 a ad — _—_ —_— — 

” 80 ” ey 3 7-4|10°7|17°8| — —- — —s An cae aeoal ee 

” 65 | 2 ==> 3 6°6|10°6| 170 | — - —_— — Ae aa 2s Be 

» | M01, )— 4 59} 9°6/13°5}182}; — | — | — | — | — — ie 

21; 85|,,| — 4 || $6) 108) 129/186) — | — |}—J oa }—}o Ps 

oo | BOF ssl — 3 61 16:6 ):17°2 | — |e ie mee ee ee ee 

” 95 ”» oer 4 2°5 74/119 18:0 | — _— — — mo — — 

22; 90);8 | — 5 30; 65) 96/150/195; — | — | — | — | — =e 

” ” ” Sd 3 6411061170} — —_— anni een pa 5 node ed + 

” 100 ” wore 3 40) 96/135) — — — — —g poe. rst wo 

” ” ” pes 4 6°6| 9°5/12°3)182| — oo — — pane pee ee 

110} ,, | — 4 i 67) $5/128/201| — | —F—|eyopto pe 

” 115 ” sa 4 30} 7:0/10°3/19°8| — — — — — — ~~ 

» | 11012) — 5 3°7| 7:5 |10°2)18°7| 201); — | — | — | — | — ne 

” ” ” = 5 38} 6°7| 9°5|12°5/19°7| — — — —_ st pe 

” ” ” Lee 3 Be 6'1 9°4 | 12°7 173| — — _— a | a Spend = 

” $ so + 4°3| 10°0 | 14:0 | 21:3 | — — —- — _ ne = 

» | 120/,,]) — 4 1 4:4) 76/1 12:8 | 20°77) —~ | — f}— | = | — | — | +> 

yo] 100-8 55 |i — 5 30} 70/11°4| 144/210} — | — | — | — | — ps © 

” 115 g Sa 4 371 5°8 | 10°5 | 21:0} — _- ca — — et = % 

” 135 ” = 5 33 70 11°1 | 15°0 | 20:0; — —— — _— a Fe 

25/150/ 3 | — 4 ‘1 490) %75/180}226| — | — f}— | HT — TS fe 

” ” ” =S 5 3°5| 54] 8:1) 12°8| 22-4) — —_— a ated See ae 

oo | 155.8 | 5 3°7| 8°3/11°0|15°0| 230}; — | — | — | — Saad fe % 

» | 150) 2 | — 4 641 9-4/13'4)204) — | — f— | sf — eS 

26;160|;4 | — 4 7°2)10°5|12°7) 23-4); — |} — | — | — | —] — a 

» |165],,}) — 5 370} 68/10°8/138°6|230; — | — | — | — |] — + 

» |1701,,/ — 4 4°1| 8°35) 146) 242; —); — |} — | — | — | — te © 

» | 180},,| — 5 36) 59] 87)152)23-'7; — | — | — }] — ro a 

” ” ” Gt 5 3°3 8°0 | 11°0 |} 14°5 | 23:2} — — — pa s- — 

» | 150/92) — 5 3°9| 9°6 | 18°2 | 17:2} 23-7; — |§ — | — | — aa ie! 

» | 170],,) — 4 Wo7l $011801926) — | — F— | Pt — jie | 


TABLES. ) 138 


TABLE XXXIVsB.—continued. 


Trout. Locality: Sannavand near Harstad. Date: August 3, 1909. 

L - S. § Calculated Length at Formation of Winter-band. 

A 2 S i ° 

‘s eo 36) & 
= 3 & ist | 2nd | srd | 4th | 5th | 6th | 7th | sth | oth | 10th | 11th 
17513) — 5 | 40] 7-0] 10°8| 144/243; —}|/ —|—]—] — | — 
» lo | — 6 | 25! 72/100) 11°8|15-7}245;} —|] —}| —}] — | — 
1901. | — 5 || 6-7| 107/123} 15-2)2468} —|—|—]|—]}— ]}] — 
ae ge 4° 0 Te Oa aes) Se Pe Pee 
1851.4 — 4 PO ep ree eto) — fae me fd | ek 
2001,,| — 5 || &8| 90/119/149/2934; —| —};—|—]—]— 
205 |, | — 5 3°8| 91) 126) 167/255) — | — | — | — | —]}— 
215|,,| — Wh es ee 06 ee ee a ee es en ee 
By ltt tye 4 | 58!106/155/248} —}|—}|/—}—|]—]|—]— 
160/9| — rE aby 3b oe ee ee ee ee ee ee oe 
180.) ,) — 4 5°5| 98)172)247; — |} —|} — | —}|—}—] — 
210:|. 55.) — 5 36} 8°7|13°2}19°2|/254); — |} — | —}|—]— ] — 
1909} 3] — 5 30} 7:0/102/143/259); — | —}|;—/[—}]—] — 
200/51 — 5 3°6| 82/110) 145/253) — | —| —|— |] — | — 
210), | — 5 3°8| 8°0| 131 | 16°8 | 25°7| - —f—{l|l—-it- i} = 
ty) 4 74/11°8)173/) 261); — | — | —}]—|—] — —s 
216} 55) — 4 54; 86/158|249) — | — | — | — |} — | — J — 
190 |-21.— 5 30! 72) 99/151/260); — | —}—}|—}]—]— 
200 fs. 6 2°5| 61) 11°7| 16-7) 249); — | —|—{|—] — | — 
220.) 5 |: <= 6 2°5| 69) 10°6| 13°7| 183/265) — | — | — | — | — 
245 ~~ 5 31} 7:2)11:1)17°7/270} — | —}—|]—]—]— 
24012); — 5 5°3| 119 | 17°7 | 20°71} 272; — | — | — | —] -— — 
rg ET Rea 5 46) 81/102 |163) 268; — |;§—]}—|—j]— See 
265; 3) — 6 3°0| 7:0] 9°6/13°1 | 213/274) — |} — | —}] — | — 
245; 2); — 5 8-0 | 12°2 | 15:3 | 20°0 | 28:3; — |} — | — | — | — | — 
250/,,/ — 5 4°4| 87/122 |20°5|280} — | — | -- | —] —- | — 
280 | ,, | 2? 5 4:3} 9°5|145|)19°2|} 264) — | — | —-/|/—}—]— 
260; 4] 2 6 3°9| 7:3} 12°1 | 182 | 20° | 292); — | — | — | — | — 
275 |,, | 2 6 3°1| 66 | 10°5 | 14°6 | 22°2| 285) — | —|—;—|{— 
285 | ,, | 2 5 4°5/11°0 | 16°2 | 20-4; 28'8| — | — | — | —} — | — 
290;,,/ — 5 41} 85/11°5/159)}269); — | —}|—/}/—]—] — 
SP et liens 5 5°7| 12°0 | 145/179} 240) — | — | — | —{|—]{— 
» to | — 6 50} 8-6) 10-2 | 13°8 | 20°7|}290) — | — |} — | — “ie 
310 /,, | 2 € 61! 8-0 | 10°7 | 13°4 | 20°2; 288; — | — | — {| — | — 
820} 5/|— 6 5°4| 10°0 | 17°0 | 21:0} 26-7; 296) — | —|—|{—]— 
265| 2); — 5 3°7| 10°8 | 13°8 | 17°8| 27°77; — | — | —|— |] — os 
285 |, | — 5 4°8/ 10°71 | 13°5 | 18°4| 265] — | — | — |; — | — | = 
2900; 4/ — 5 5°4| 12:0 | 189 | 25°7 | 20°83} — | — | — | — | — ir 
pe a es 6 . || 68} 93] 13-7} 17-:0| 249/305; — | —}|—]}] — | — 
$16 |, | — 5 7°0| 10°8 | 18°2 | 21:0} 292} — | — | — | — | — ao 
310*2}; — 5 7°5 | 13°5 | 19°0 | 26°3 | 303} — | — | — | — | — a 
320/|,,| — 6 4:0) 85 | 14°5| 18°5 | 20°'7| 306); — | — | — | — | — 
FPN Rts (beac 6 5°5| 80) 10°5 | 13°5 | 15°5 | 259) — | — | — | — | — 
380 | ,, | — 6 4°7| 93 13°6 | 16°3 | 24:0;300} — | — | — | — sie 
320; $ | 2 6 7°5| 11°8 | 16°2 | 20°2 | 27°8| 309; — | — | —}] — amet 


* 


io) 


184 THE 


AGE AND GROWTH OF SALMON AND TROUT. 


TABLE XXXIVs.—continued. 


Trout. Locality: Sannavand near Harstad. Date : August 3, 1909. 
g| & v § 
= iw} Calculated Length at Formation of Winter-band. 
| | A a] 
4 # | Sex. SF = 
eRe 2 5 s 3 
Sle £ & ist | 2nd | srd | 4th | Sth | oth | 7th | sth | oth | 10th | 11th 
91/383 |325| 3} — 6 3°5| 8°0| 11°7 | 20:0 | 26-7) 315; — | — | —|— | — 
92) ,, | 3830) ,, | 2 5 3°9| 9:°2/16°7| 200/280; — | — | — | — |] — | — 
Bat 1400 Lae hte 5 | 43] 98|13°8/ 210/301} — | — | —}—}] — | — 
94| ,, |315| 9] — 6 || 33] 65] 10°0| 153 | 25:7}301} — | —}| —| — | — 
95| ,, | 350 | ,, | 1—2 6 2°8| 7°7|10°8| 15°8 | 2441316) — | — | — | — pds 
96| ,,|390|,, | 3 5P | 3:4) 66) 102) 17:5) 275) — P}|—{|—f]—f]— 
97 | 34| 340 | gf | 2? 7 6°2} 9°7 | 12:3 | 15°9 | 19°4 | 28°6 | 325; — | — | — | — 
98} ,, | 350/,, | — 7 3°0;| 8:2} 10°8 | 14°5 | 19°4} 26°9 | 316) — | — | — | — 
99| ,, |} 480 |,, | 2 6 4:2) 7°8| 12°8} 20°0| 265/316; — | — | — | — | — 
100| ,, |350| 2] 3 7 | 61] 96) 11-7|14-9]19°9| 275/325} — | — | — | — 
101} ,, | 390 | ,, | 2? 6 3:3) 77 | 9:9 | 185 |} 275/328) — | — | — |] — |] — 
102; ,, | 400/,, | — 6 4°5| 8:0} 10°3 | 16°1 | 24:7} 820) — | — | — }] — | — 
ee RS ee 5 || 65| 10°7|13°8| 20:0| 305] — | — | —}|— |] — |] — 
104 | ,, ” ” 3 6 43} 8°2|11:1|)170/199|29°8| — — = — — 
105 | 35 | 450 | gf | 2? 7 3°5| 7°2| 10°6 | 16-0 | 20°0 | 29°3 | 30:2; — | — | — | — 
106 | 36 | 470 | ,, oe 6 6°5 | 10°4 | 15°9 | 20:2 | 25-7 | 318] — | — | — | — |] — 
107| ,, | 500 | 9 | 2 7 3°0| 6°3 | 10°8 | 16:2 | 25:1 | 31°0| 346) — | — |} — | — | 
108 | 37 | 450 | ,, | — 6 3°7| 66} 11°3 | 19°6 | 28°8| 342) — | — | —] — | — 
109 | 39 | 650 | gf | — 8 3°0| 6°3 | 10°3 | 16°8 | 25-0 | 30°5 | 35:0 | 87°7; — | — | — ‘ 
110|42|700 | 9 | 2(7)| 8? || 5:2] 8-7} 12-7 | 20:0 | 25°8 | 32:0} 40-1 |41:177 — | — | — 
111 | 44 | 800 | ,, | 3—4 9 5°4| 11°0 | 15°4 | 20°1 | 25°5 | 34°3 | 39-2 | 41°7| 429} — | — 
112|46) , | S| 2 9 5°1| 9°4| 16°6 | 20°4 | 24-0 | 34°5 | 37°99 | 42°9/ 445] — | — 
113 | 47 | 950 | 9 | 2(7) 10? || 7°2| 12°0 | 17°8 | 23°0 | 28°3 | 35°5 | 42°2 | 48-8 | 45°3?| 46-4? | — 
114} 48/900 | g| 2 9 4°4 | 13°0 | 20°7 | 26-4 | 31°8 | 37°6 | 41°7 | 45°2 | 471] — | — } 
115 | 49] 4,15, yy» | 11—12 || 7:2 | 10°6 | 15°6 | 18-7 | 28°3 | 32°5 | 36°9 | 39-8 | 42°1 | 45°5 | 48-2? 
| 
Average length in cm. . 4:9) 8°9 | 13°0 | 18°4 | 24°6 | 30°5 | 36°2 | 41°7 | 444 | 46°0 | 48°2 
’ 


Trout.! 


TABLES. 


TABLE XXXV. 


Locality : Chaigijok (Lakselyv). 


Date: July 15—20, 1909. 


185 


Birth-year, 


1907 


1906 


1905 


1904 


1901 


Length in cm. 
Number of Fish 
Examined. 


2 winters. 


8 winters, 


4 winters. 


$ 


Tot. 


zs 


Tot. 


8 
st 


Oy 


0 


To 


st 


+0 


ee 
PITT E LITTLE ETT TA 11 err |e 


PT TPTAT IPT bee TT 
Phi dtd tid bbbidbted dell tl 
PEEP PEELE EEL TTT ween l 1d | 
PLT L TEL LL TA romeo! | dl | 
PELE ELT EEL Lob ocomecnol Idd | 
LLL TELL ELL Lew eaSeanl | It 
PET ETL TD bromer eel Pitt tl 


FETT E LL] erm cornwell 1d td 


LTTE TTL LT Leccomoccwce! 11 tt | 


bed dtlt p eee esdebok bei Ek 


Lib bd et eeool lt LITT 


a en Oe 


BeSeSr eee eeasaas 


PORE SPP RSS RRA wars Fee, 


booted eco Ld ere ei 


Td) btdelblittbi bhi tbitl 


PERBGESAETE SOc eae eR eS 


PEPER PERT TAT TTT ET ITT | 


ete AY Ha EEE eee td 


» 


© 


ag 


— 
nr 
a 


& 


a" 
@ 


34 
17°4 


= 
= 


23 
19°7 


aS 


oO 


25°0 


is) 


bo 


| 


1 Taken with fly. 


THE AGE AND GROWTH OF SALMON AND TROUT. 


136 
TABLE XXXVs. 
Trout. Locality: Chaigijok. Date: July 15—20, 1909. 

¥ a 33 Calculated Length at Formation of Winter-band. 

# |86|/ 35] gy [a8 e8 

4) 8s le Z r RB Psu] moa | ee | ae oe P| a 

1 10 | 10 g°\-— 2 3°5 | 82 _- — — oe ids ona 

2 12 15 $ _ 2 61 | 10°7 = —_ — =e nan ae 

3 ” ” 2 — 2 6&7 |107) — = tal a a) fl 

4 ” ” ” ay 2 5°8 9°8 ‘tr rE Zi er | ae rae! — 

5 13 | 20 —_— 2 69 | 12:0 —- — — how “ae dein 

Obs By 89 | 108 feed eet ned ty ae 

hte 8051. | te ee | tod |e ek ee 

8 < 25 — 2 68 | 10°8 — — _ ja ns ie 

9] » i fia ee OB | 92 1990 fi aed Rot ef ae 
10-40 5 1 | ple pee 66 | 80) 180 it] 4 ee 
2 -146-1-60: + 3) 9 eta) | ist fh me Peo oe eee 
1B bc ee 1 cost fee fee a? | 93: |:208 | 160) ] | a Ot ae 
3°) 'S be lol) 3 (eeese | 69 [104] 140) 4 foie 
41 ibe] oll’ e 1 eee gO | 891 11S 1 4eny 22) ee 
16 | of 88 | ol 1 | eR SO-| 07 1100 Peep et ef 
1 1), | 90)| 9.) — [oe hies |.8-7 | 110 F180) = | —} — fe 
17 ” ” ” cm 4 4-1 69 | 10°1 | 140 — _ eects se 
18 16 | 35 3 _ 4 3°6 75 | 118 | 151 — — —_ — 
19 Pa 40 . 2 4 4°4 8°7 |} 1271160}; — —_ pa pd 
20 ” 45 ” — 3 4°4 98 | 13°8 = — _— monte =e 
21 ¥s 35 2 2 5 49 | 88 | 114] 1384/)1560) — —_ — 
22 = 40 ms —_— 4 39 | 84 | 12°8 | 1571 — as —_ — 
6 iL gh oem ESO | 04 |. 207 2 1GO Pee: Pee te 
Ml ig ilew bool le at | 08 | 18 140 | oe fe 
25 17 45 $ _ 4 46 | 104 | 143 | 160) — —- —_ os 
26 . ” ” or 4 39 82 11°7 14°8 x —_ —_ ome 
| nil aw | ott 2a Oe | 86 | 101 163) 1] eS 
a3 | ” » | — | 41 40] 841128] 166| — | —| —|] — 
29 be os “ 2 4 4°7 92 | 129 | 15°8 — _ -- — 
30 se ‘a = 2P | 6 4°7 85 | 108 | 1389 | 160; — — — 
Sth eck ot | Be On O48 | 00:1 :1601 uh Lee | eet 
Mfc tlw | wil 8 1 O18 £0 1 176 | 118) 1607 4 | = PS ee 
33 | , | 40/ ¢|—| 4446] 96|121/144/ —| —]| —]| — 
ae Lm LO} 804-119 [386 1 = | ie 
Bi. lw), | —-t ee7 | 61 | 10818 1166) — |) ee 
36 ne a om — 4 39 90 |} 126)}160); — — — — 
bal et — ee ae | 78 | 108 [968 | — 1 ee 
bo di lw 1 Se ee ts | 166 1H bo) Se 
39 |. | 66], |1—2| & | 41 | 82) 129]148] 169] — | — | — 
40 18 PA $ — 4 69 | 12°3 | 14°5 | 16°4 — —- — — 
at Pl. | — ea 910 | 196 1 108 Fob oe ee 
42 as 60 os == 5 43 8-1 | 12°8 | 14°99 | 16°9 — — ~~ 
43.1 5 | we lim | 8 Le eee | 100 | 147 1 160 | — eee | 
aa} ood ol hy RHO Bee 80. | 117 | 166 | ee ee | oe 
45 = 45 2 2 5 4°9 8°6 | 12°6 | 15°5 | 17°2 — — a 
46 ¥ 50 Pe oe 5 41 7°8 | 11°5 | 15°4 | 17:2 — — _ 
Mio liad o | 2 he Os fb 87 | 196 1 160 fH] 


—: 7 


TABLES. 187 


TABLE XXXV3B.—continued. 


Trout. Locality : Chaigijok. Date: July 15—20, 1909. 
“6 
2° =I ; Calculated Length at Formation of Winter-band. 
| $3/38| y [SB \ ef 
8 Co ed 

a] 88 | e4 z 8 <= | ist | ona | sra | ath | sth | oth | 7th | sth, 
48 | 18 | 65 | 9 -| — | 4 WA GIO? | 14°F 1173S) es — bo ibe en] le 
49 ” ” ” aren 4 49 8°7 13°7 16°9 _ — — — 
50 9 | 65 | .3.|.2—-3)..6 50 | 941/130 |160/)180}/ — | — | — 
51 ” 75 ” 3 4 4°6 10°0 15°9 17°9 _ _ —_ -— 
52 os. (60-4. 2 +i 46 | 9°5 | 12°3 | 15:5 | 182 | —sj;— | — 
53 ” 60 ” as 4 5:0 9°5 13°1 17°7 — _— —_ — 
54 ” ” ” ~~ 4 5°3 | 10°6 | 14°6 | 17°5 —_— _— — — 
55 ” ” ” 2 5 4:2 7°4 12°2 16°3 18°0 _ _ ss 
56 ” ” ” 2 5 4°5 8°7 12°4 15°6 17°8 ase — _ 
57 io a 9 3 5 eS bo O'4 1:18°D; | 17-2: |182 [Had — 
58 apf BBL sy chem Be bey Bek eT [127% | 16°F 1.8 bd ee 
59 ” ” ” — | 6 4-1 78 10°9 15°5 .| 18°70 ss aes — 
60 ” ” ” 3 5 4°3 78 12°4 16°3 17°8 —_— —_ —- 
61 » | 7 | » | — | 6 50 | 10°2 | 128 | 153 |}180} — | —] — 
O24) 20' | 6F | S ben ht 4 4-6 1.10°7 | 14°7 |. 186 fj —. | — | — | i 
63 deat TOF he yi — bb 56 | 10°3 | 18°5 | 167 | 190} — | — | — 
64 es ee eae 2 5 39 | 91.|181/160/192;/ —}|—| — 
65 ” ” ” 2 4 58 11°9 17°% 19°4 _ — —— — 
66 sot BHT -g 2 5 46 | 90 | 18:3 | 172 )194}; — | — sas 
67 ” 70 ” oad 5 4°4 9°8 13°9 173 19°1 a ames) —_ 
68 Me ‘ és 2 5 i776 | 134:|'168 1 101 | —" |" | — 
69 * ¥* 2 5 48 | 941134 |163}184)—/]/—}— 
70 1-26 2 5 Meet S4-1-18° 1 16,1909. 1 — | — | = 
71 >» | @ttse 2 5 4:11) 06 1187 | 1731199 | — | — | — 
Sg OS Bae ga ee 39 | 10°5 | 153 | 184 | 202) — | — | — 
73 a + - 2 5 61} 88 | 120 |162/197 | —|—|] — 
74 ” ai 4 3 5 S64) 88 | 190) 166) 167 [ph er oS 
75 » | 105] 4, 3 6 60 | 11°8 | 16°6 | 18-2 | 19°3 | 202} — | — 
76 * 75|-Q 2? | 5 68 | 126 | 15°7 | 182}195 |} — | — | — 
77 %» 3 3 3 6 48 | 85 | 1221/1158 |185 | 200} — | — 
78 ” °° » 3 6 43 | 95 | 184 1162/181]198 | — | — 
79 » | SOY Qi] 4 &7 | 109 1166 1.197} —|.—}— |] — 
80 % ” ” 2 6 49 | 95 | 126 | 1521176 }201 | — | — 
81 % 9% # 2 6 4°7 | 95 | 12°8 | 16-7 | 19°0 | 202}; — | — 
82 9 Es ” 2 4 BS FISH PSS 1 IOS fe Pe ee Oe 
83 0 9 ” 3 6 45 | 86 | 122 | 156/183 | 201 | — asin 
84 » | 85 | 4 3 6 39 | 72 | 12°0 | 15-7 | 182 | 202 | — — 
85 | 22 | 90 3 6 44 |} 80 | 13°0 | 156 119°0 | 211} — | — 
86 oy PROD T Gg 3 5 58 | 95 | 1431182 )209} — | —] — 
87 » | 90 | 2 |1—21 6 45 | 99° 18-7 [47-6 1} OF) — ft — |} = 
88 » 196 | ws 12-21 6 4°4 | 10°2 | 15°0 | 18°7 | 210} — | — | — 
89 9 9 ” 2 6 7-0 | 111 | 13°8 | 16°4 | 19°1 | 21:3 | — _ 
90 »» |100 | 4, 3 6 5°7 | 11°4 | 15°6 | 18°0 | 20°71 | 214] — | — 
91 196 ho 2 6 4:2 | 91 1]133 | 168 |189 | 212} — | — 
92 | 23 |105 2 5 39 | 86 | 129 1173 |219|/ — | —| — 
93 wet dl0 | 3 5 46| 97 |146|192|222/ — | — | — 
94 - 1100 | o | — 16 35 | 68 | 101 | 13-9 | 188 | 221) — | — 


188 THERE AGE AND GROWTH OF SALMON AND TROUT. 


TABLE XXXVB.—continued. 


Trout, Locality : Chaigijok. Date: July 15—20, 1909. 
: St «9 Calculated Length at Formation of Winter-band. 

& FF Sb) x | sb|¢ 

’ co a 

= 4.) = or a5 Ist | 2nd | sra | 4th | sth | oth | 7th | 8th 

95} 28 |100'| ¢ | 1a Pee ee fk eee Foe ee 

96 ‘ a sk 2 5 8:1 | 15°4 | 19°0 | 21°2 | 22°4 oo — — 

97 As AS am 3 6 48 85 | 12°0 | 16°0 | 19°0 | 21°3 a= — 

98 ‘5 ue + 3 6 5°4 | 10°3 | 14:2 | 18:1 | 20°2 | 22°3 — _- 

99 soe os 2 6 5°0 | 10°4 | 14°5 | 16°9 | 20°71 | 22°4 — -—— 
100 | 24 oe $ 2 6 46 | 10°6 | 15°3 | 18°2 | 21°5 | 23°0 — — 
101| ,, 11835 | ,, | 2 | 7 | 81 | 102 | 152 | 17-5 | 198 | 21-9 | 231 | — 
102 » |150 eH 2 7 4°3 9°8 | 15°0 | 17-4 | 19°9 | 21°8 | 23:3 o 
103 | 25 |125 28 2 — Useless, 
104 » |180 M4 2 6 5'1 8:6 | 12°9 | 17°0 | 20°7 | 23°6 — -- 
105 » | 145 a 2 8 55 | 11°4 | 14°8 | 17:2 | 19°83 | 21°2 | 23:2: | 243 
106 » | 150 % 2 7 3°7 8-2 | 11°3 | 15°9 | 18:6 | 21°3 | 24:2 — 
107 MS is + 2 8 5:0 9°3 | 18°1 | 14:9 | 17:4 | 19°7 | 22°0 | 24-1 
108 » |140 2 2?) 6 76 | 13°3 | 16°0 | 19°3 | 22°3 | 24°3 —- — 
109 | ,, a nS 3 = Useless. 
110 | 26 |155 $ 2 7 4°6 77 | 18-0 | 17:0 | 19°9 | 23:0 | 25°4 | a 
111 1100 ‘ 2 7 4:0 | 75 | 11°0 | 149 | 188 22°0 | 25°2 ooo 

Average length incem. | 49 | 9°5 | 13°2 | 16-4 | 18°6 


21°4 | 23°8 | 24°2 


TABLES. 139 
TABLE XXXVI. 
Trout.? Locality : Luostijok. Date: July 17—September 4, 1909. 
3 6 d|\ 3s Hf ae ~ Calculated Length at Formation of Winter-band. 
g° tbe 5 4 &s ; 
4 | 58) 24 m3 \“5 || ast | ona | ara | ath | oth] oth | rtm | stn | oth | 0tn | 1th 
1; 27); — | 8 | —| 5 | 49)11°3)15:1/17°8) 21-8; — |; —| —} —}| —|] — 
2/32; —|, |—| 61389] 88) 145/178) 21-9| 275; — | —} —| —} — 
8i 5 | — | @l|—{ 8 48] 9-4) 112) 151 | 17-7 | 20-7) 23°8 | 28-0; — |} —| — 
4;36| — | &|—]| 61439] 9°7|15°6|19°9)| 26-9;33-:0; — | —; —] —}| — 
5} 5, | — |. |—| 6 38] 11-0|17°3| 20:3 | 24-1]}29-9} —} —}| —}| —| — 
6 | 37 | 500 1| 9 | 53) 7:6) 103 | 13°7 | 18-1 | 21-2 |.24-7 | 29-3} 35:0} — | — 
7|}39|— |, |—| 6 3:9) 971) 14°8] 22-1 | 28:2/34-7; — | —| —}| —}-— 
8} 41} — | & | —| 11 |/3°7| 8-7] 10°5 | 14-4 | 16-4 | 19°6 | 23-0 | 25°3 | 27-7 | 30-2 | 36°6 
9)» | — | 2 1—l 9 44] 7-4) 1271) 14°6 | 16°5 | 20-9 | 23°9 | 27-7 |:35°9| — | — 
10 | 42} — | & | — | 10 || 4°9| 10°1} 12-0| 14-7 | 16-7 | 18-9 | 22-2 | 26-4 32°3| 37-2} — 
11} 43} — |} 2 | — | 10 | 3:7] 8:8) 11°0| 14°3| 17:9 | 22:3 | 26°7 | 31°2 | 36°8|40°6| — 
12 | 44} — | & | —] 11 38) 7:0) 10°8 | 14-0 | 16-4 | 18:8 | 23-2 | 27°8 | 33°6 | 38-5 | 41-8 
13 | 45 |}1000| @ 3 | 10 || 4:3) 88} 12°8| 17-5 | 20°7 | 23-7) 28°3 | 33°6 | 38°5 | 42-7} — 
14 | 47 | 950) $ 2 | 11 3:8) 6°8| 8°9| 12:2) 17-0 | 20°6 | 25°5 | 31°9 | 36°9 | 41-2 | 45-2 
15 | 48 | — | @ | —|{ 10 || 7:0} 10°6/ 12°6| 16-5 | 18-7 | 21°0 | 24°6 | 34°35 | 40-6 | 47:1; — 
Average length in cm. . - || 44) 9°0| 12°6| 16-3 | 20°5 | 23°8| 24-6] 30°6) 35-3] 39°7| 41:2 
1 Taken with spinner and gill-net, 2 Examined only in three fish. 
TABLE XXXVII. 
Trout.? Locality: Gagavand. Date: August 27—September 18, 1909. 
; Calculated Length at Formation of Winter-band, 
nono, | Haat |e | gh 

Ist | 2nd | 8rd | 4th | 5th | 6th | 7th | sth | 9th | 10th 
1 32 $ 5 4:1) 9°5 | 14°8 | 21-4 | 284); — | — | — | — | — 
2 34 g 6 4°4| 9°8 | 14°6/ 18°0 | 21:2 | 285) — | — |; — | — 
3 35 a 6 3°8 | 9°6| 15°8 | 19°5 | 22:3 | 283) — | — | — | — 
4 us i 7 6°4 | 10°5 | 14°3 | 17-0 | 20°7 | 24-4 | 30-2; — | — | — 
5 36 $5 7 3°6 | 7°5 | 11°56 | 17°7 | 21-4 | 27°41 31-7; — | — | — 
6 38 3 6 4°5| 9°7 | 14°5 | 18-4 | 20:4 | 32:2) — | — | — | — 
7 39 i 6 |4:8] 9:4] 181 | 21-4] 273/343) — | — | — | — 
8 40 2 7 7°5 | 11°7 | 16°5 | 21:2 | 26-7 | 32-0 | 36-8 | — | — | — 
9 45 $ 8 6°2 | 10°4 | 14°6 | 18°9 | 22°7 | 26-7 | 836-4 | 42-4; — | — 
10 66 Pe 10 || 7°5 | 13-2 | 17°0 | 19°5 | 22°5 | 2671 | 35°5 | 50°5 | 60°0 | 64°5 
Average length in cm. 5°3 | 10°1 | 15°7 | 19°3 | 23°4 | 28°9 | 34°1 | 46°5) 60°0) 64°5 


1 Taken with gill-nets, 


140 THE AGE AND GROWTH OF SALMON AND TROUT. 


TABLE XXXVIII. 
AVERAGE WEIGHT OF TROUT OF DIFFERENT LENGTH. 


Number Average Length Number Average Number Average 
ee | pots, | Gokinee | em |akrima,| Sialieet || loom |achettea | Sasinae 
10 2 85 41 4 600°0 71 4 4187°5 
il 13 11°2 42 6 750°0 72 5 4530°0 
12 12 13°8 43 3 800°0 73 3 4966°7 
13 39 19°1 44 4 787°5 74 4 4500°0 
14 32 23°1 45 2 950°0 75 3 5066°7 
15 41 28°5 46 2 800°0 76 4 5350°0 
16 30 34°4 47 5 1050°0 77 4 5475°0 
17 28 41°0 48 5 1080°0 78 4 6075°0 
18 20 50°0 49 5 1150°0 79 4 5600°0 
19 26 59°2 50 2 1475°0 80 — — 
20 30 67°8 51 3 1300°0 81 2 6725°0 
21 32 789 52 1 1500°0 82 2 7325°0 
22 41 93°0 53 4 1595°0 83 2 7150°0 
23 29 108°8 53°5 1 1700-0 84 2 6800°0 
24 45 119°4 54 3 1333°3 85 2 6820°0 
25 24 1379 55 8 1611°4 86 4 8275°0 
26 20 159°5 56 6 1941°7 87 3 8833°3 
27 30 1842 57 3 1866°7 88 1 7600°0 
28 26 204°8 58 2 2175°0 89 1 8000°0 
29 22 222°5 59 4 2400°0 90 4 8412°5 
30 17 247°9 60 8 2412°5 91 1 9000°0 
31 30 280°2 61 12 2560°0 92 2 9125°0 
32 21 302°6 62 6 2438°3 93 _ —_ 
33 24 352°9 63 3 2590°0 94 1 9650°0 
34 27 360°9 64 6 2983°3 95 — —_ 
35 11 421°8 65 9 3077°8 96 1 11700°0 
36. 11 505°9 66 7 3264°3 97 _ one 
37 8 509°4 67 6 3441°7 98 1 11150°0 
38 6 511°7 68 3 3733°3 99 1 11600°0 
39 5 560°0 69 8 3915°0 — — — 
40 4 580°0 70 9 4083°3 —_ — _ 


8.T. 


METRIC WEIGHTS AND MEASURES. 


Lbs. 

4... 23 
Q2= ‘44 
38= ‘66 
4= ‘88 
Bias 1°10 
6 = 1°32 
7 = 1°54 
8 = 1°76 
9 = 1°98 
10 = 2°20 


A. WEIGHT. 
Kilo Lbs. 
1.= 2205 
2— 4409 
8= 6614 
4= 8818 
5 = 11°023 
6 = 18°227 
7 = 15°482 
8 = 17°687 
- 9 = 19°842 
10 = 22°046 
B. Leneru. 


, Kilo. 


Lbs. 
11 = 24°251 
12 = 26°455 
13 = 28°660 
14 = 80°864 
15 = 38°069 
16 = 85°274 
17 = 87°478 
18 = 39°688 
19 = 41°888 
20 = 44:092 


10 millimetres = 1 centimetre = 0°3937 inch. 


Cm. Ins. 
5= 1°968 
10:= 8987 
15 = 5°906 
20 = 7°874 
25 = 9848 
80 = 11°811 
85 = 138°780 
40 = 15°748 
45 = 17°717 
50 = 19°685 


Cm. Ins. 
55 = 21°654 
60 = 23°622 
65 = 25°591 
70 = 27°559 
75 = 29°528 
80 = 81°496 
85 = 38°465 
90 = 35°4338 
95 = 87°402 

100 = 89°370 


THE AGE AND GROWTH OF SALMON AND TROUT. 


1000 grammes = 10 hectograms = 1 kilogram = 2°204622 lbs. 
Hectos. 


10 


141 


yal gS Le 
HET 

b By nas 34 
eae 

: i 2 

‘ ban Oy “= 
RRO se 
AUTH sh 


wt 


ae 


aoe * 
3" 


ay’ 
al 


ii 


Re RE oe ABR MRE ae 
+ “OTONE emt. BON QL = ORS 


Se or ay 


= ace £06 


Fig. 8.—ScALE oF IMMATURE GRILSE, 26 OM. 
Sandeidfjord, July—August, 1908 x 34. 


Fic. 12.—ScaLe oF SALMON, 29 KGR. 


Fic. 9.—ScaLE oF GRILSE, 57 OM., 1°9 KGR. 
Topdalsfjord, July 8, 1909 x 16. (Hutton fot.) 


Vic. 108. —CENTRE OF SCALE X 40. 


—— >» 
— 


PL. 


118.—CENTRE OF SCALE X 40. 


Fic. 


Fic. 11.—ScaLE oF SALmon, 96 om., 10°5 KGR. 


(Hutton fot.) 


Buoones. :Svd-Varancer. June 9. 1909 * 14. 


Pie y. 


lic. 14.—ScaLE oF SALMON, 73 om. (SLIGHTLY Worn). 
Tierdalselvy, October, 1909 x 16. 


Fic. 15.—Scate oF SAutmon,:.80:cm. (MODERATELY Worn). 
Lerdalselvy, October, 1909 x 16. (Hutton fot.) 


Fic. 16.—ScaLe oF SAutmon, 82 om. (Muon Wory). 
Leerdalselv, October, 1909 x 16. 


Fig. 18.—SoaLE or SALMon, 84 om., 6°4 KGR. (1 SPAWNING MARK). 
Mandal, June 5, 1 


Dh. 


Vill. 


Fic. 22.—ScaLE oF Msgsen Trout, 56 om., 2:0 KGR. 
Laagen, August 15, 1909 x 27. 


PANS 
yy AN 


a Sa By 


rr 


a eS oa ae | 


Fic. 24.--ScaALE OF MJ@SEN TRovT, 81 om., 6:0 KGR. 
Laagen, August 2, 1909 x 16. 


ee 


a, 


to ee ee a 


Fic. 25.—ScaLE oF MJgsEN TROUT, 99 cM., 116 KGR. 
Laagen, September 2, 1909 x 14. (Hutton fot.) 


ely BM & 


Ada 


€ 
t 


33.—ScALE OF TROUT, 36 cM., 650 GRAMMES. 


Fic. 


Laugen, Trondenes, August, 1909 x 35. 


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