SPRING AND SUMMER DISTRIBUTION
OF HADDOCK ON GEORGES BANK

I,

iMarine Biological Laboratory|

JUL 2 7 Vdbb
WOODS HOLE, MASS.

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SPECIAL SCIENTIFIC REPORT- FISHERIES No. 156

UNITED STATES DEPARTMENT OF THE INTERIOR
FISH AND WILDLIFE SERVICE

EXPLANATORY NOTE

The series embodies results of investigations, usually
of restricted scope, intended to aid or direct management
or utilization practices and as guides for administrative
or legislative action, it is issued in limited quantities for
official use of Federal, State or cooperating agencies and in
processed form for economy and to avoid delay in publication

United States Department of the Interior, Douglas McKay, Secretary
Fish and Wildlife Service, John L. Farley, Director

SPRING AND SUMMER DISTRIBUTION OF HADDOCK
ON GEORGES BANK

By

John B. Colton
Fishery Biologist

Special Scientific Report: Fisheries No. 156

Washington, D.C.
June 1955

ABSTRACT

This part of the study of the Georges Bank census data treats of the total
age, and the age distribution of haddock over the Bank, by statistical subarea, by
depth, and by bottom type in the years 1948, 1949, and 1950.

The total abundance and the age composition varied markedly from year to
year and emphasized the effect of certain year classes on the catch .

TTie distribution by subarea demonstrated that the fish were concentrated in
certain subareas and tJiat the age composition of the catch varied with location. This
distribution shifted slightly from summer to spring with the total abundance being
greatest in subareas J and M in summer and greatest in subarea N m spring. The
abundance -of older haddock was consistently greater in subareas G and H than over
the rest of the bank.

The depth distribution of mature fish varied with the season and appeared
to be linked with the spawning and feeding migrations , In summer, greater numbers
and heavier 5 -year -old and older haddock were caught in water deeper than 90 fathoms,
but in spring these older haddock were found in shoaler water . Few haddock of any
age were found in dep'iis between 60 ar;d 90 fathoms during the summer months .

Haddock occurred in greater numbers over sand than over mud bottoms, but
this distribution was incidental to the depth distribution.

Mortalities, although based on 2 years' data, were consistent and decreased
with the increasing age of the fish and their decreasing availability to commercial
capture .

Age -composition data of the commercial catch and of the census data, when
weighted in terms of effort of the commercial fleet, were similar, a fact which
attests to the reliability of the sampling methods .

Estimates of year-class strenglJi based on the relative numbers of zero -ring
haddock determined from census tows were substantiated by the catch of these year
classes in subsequent years during census cruises and by the commercial fleet.

CONTENTS

Page

Introductiom .................................................... 1

Methods .................................................... 2

Results .................................................... 5

Abundance and age composition for Georges Bank 5

Summer ........................................... 5

Spring ........................................... 12

Abundance and age composition in individual subareas ......... 14

Summer ........................................... 14

Spring ........................................... 20

Abundance and age composition as related to depth ............ 20

Summer ........................................... 20

Spring 29

Abundance and age composition as related to bottom type ...... 34

Summer ........................................... 34

Spring ............................................ 39

Comparison of census and commercial data ................... 39

Summary and conclusions 49

Bibliography ...................................................... 51

Appendix ......................................................... 54

SPRING AND SUMMER DISTRIBUTION OF HADDOCK
ON GEORGES BANK

INTRODUCTION

Systematic surveys of the populations of bottom fish in the Georges Bank area
were made by the Fish and Wildlife Service vessel Albatross III during the summers
of 1948 and 1949 and in the spring and summer of 1950. These surveys were con-
ducted to estimate the size and composition of the populations of haddock and other
species of demersal fish and to obtain information on distribution, movements, year
class strength, and growth rates in relation to environmental conditions . This paper
presents an analysis of the distribuHoE of haddock (Meianogrammus aeglifinus) by
area, depth, bottom type, season, and year .

The basic assumptions underlying this program were as follows:

1 . The efficiency of any fishing gear remains constant, although it may
vary with different species. Thus the catches of the net from different places and at
different times are comparable .

2. The size and distribution of the population sampled does not change
significantly during a short period, and thus all samples taken during this period are
samples of the same area.

TTie distribution of the commercial catch in the Georges Bank area in time
and space is well established from records collected over a number of years. These
records show that the distribution varies somewhat with age of the fish and season of
the year and that the population is not evenly distributed by area or depth. (Schuck
1952). Since the commercial fishermen concentrate their efforts in particular
localities and depths and on certain sizes and species of fish (notably haddock), and
since there is little uniformity in the size and the efficiency of the boats and gear used,
these catch records do not give an accurate record of the distribution of the population
over the bank. It was necessary, then, to establish a sampling program which insured
the following:

1 . Standardization of gear and methods .

2. A complete coverage of the bank in as short a time as possible.

3 . Uniform sampling of all areas and depths of the bank .

Eh: . William F . Royce and Howard A . Schuck planned the sampling program .
Numerous persons assisted in the collection of data at sea. I am indebted to Captain
John T. Collins and the crew of the Albatross III for their willing assistance and co-
operation and to biologists E. D. Premetz, R. E. Sayles, E. L. Arnold, J. R.
Webster, R. J.Buller, E. L. Miles, J. R. Clark, and R. E Kirkpatrick, who took
part in many cruises.

Age determinations from scales were made by E. L^-Arnold; R. E. Sayles
and R. R. Marak assisted in compilation of catch records; and C. C. Taylor offered
valuable suggestions and advice in the analysis of the data.

METHODS

Sampling Techniques

Adequate representation of all areas and depths was accomplished in the
following manner:

1. The total area of Georges Bank within a limiting depth of 150 fathoms
was computed and, using 8iie statistical divisions of Rounsefell (1948), the total square
mileage of subareas, G, H, J, M, N, and O were likewise determined.

2. The region to be sampled was further subdivided into unit areas of 10
minutes latitude by 10 minutes longitude. These unit areas represented potential trawl-
ing stations . The percentage which the number of unit areas in each subarea
represented of the total number of unit areas in the region of sampling was then
computed.

3. The number of samples that could be taken within a definite time limit,
approximately one month, was estimated and this number was prorated to each of the
subareas on the basis of their area.

4. Three depth zones were established as follows:

(a) Depth zone I: 0-30 fathoms.

(b) Depth zone II: 31 -60 fathoms.

(c) Depth zone III: 61-150 fathoms.

The percentage of each subarea lying within each of the three depth zones was
then determined and the total number of samples to be taken in each subarea was pro-
rated to each depth zone on the basis of these percentages .

After determining the number of stations to be allotted to each subarea and
to each depth zone within each subarea, the stations to be occupied were determined
by numbering the possible stations and selecting the ones to be occupied from a table
of random numbers (Fisher and Yates, 1943). This random selection was restricted
so that not more than three stations could be adjoining. To provide a measure of
variability between tows, 2 tows were made at random stations in 1948 and at every
third station in 1949 and 1950.

The area and subarea boundaries and distribution of stations are shown in
figure 1 .

Georges Bank was sampled in this manner in the following months and years:

Year Months

1948 July - October

1949 July - August

1950 April

1950 July - August

The catch per tow was adopted as an index of abundance. In the age classifica-
tion of haddock, it is assumed that haddock spawn in February and hence a haddock-
year extends from February of one year to February of the following year . Haddock
which were spawned the preceding February and hence in their first year of life are
referred to here as zero-ring haddock, and are fish~with.no anwilus on their scales.
Fish in their second year of life, having scales with one annulus are called one -year-
olds (I -ring), fish m their third year, two-year-olds (II -ring), and so on. The category,
nine -year-olds, includes the nine-year-old and all older fish. Age readings were
determined from scales obtained from fish caught during census cruise&and by the
commercial fleet in corresponding periods .

The gear used was a slightly modified No. 1-1/2 Iceland Trawl with dimensions
as follows: 78 ft. head rope; 114 ft. foot rope; 6 -inch mesh in the wings and square;
5-inch, tapering to 4 -inch, mesh in the belly; and 4 -inch mesh in the cod end. The
cod end and upper belly were lined with 1-1/2 -inch mesh cotton twine, as earlier ex-
perimentsiiad shown that these were the places where most of the small fish pass
througji the mesh. The entire net was approximately 100 feet long and was attached
to the doors by rope pennants 30 feet long. The doors were fastened directly to the
towing warps. Three 20-foot sections of wooden rollers were used, the largest of
which were about 18 inches in diameter and 4 to 6 inches in width.

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The trawl was towed for i/2-t:iOur at a towing speed of approximately 4.5
knots with each tow being made within the unit area boundary and in the same depth
(^ 10 fathoms) wherever possible.

At each station the following additional observations and collections were
made:

1 . Bathythermograph and stirface temperature readings .

2. Bottom samples by means of a scoop-fish bottom sampler
attached to the nose of the bathythermograph.

3 . Lor an fixes at the beginning and end of each tow .

4. Fathometer records.

5. Counts or accurate estimates of the number of fish and the
number of bushels of fish of all species.

6. Length measurements of all haddock and of other species
as time permitted.

7. Scale samples of as many haddock as possible.

RESULTS

Abundance and Age Composition for Georges Bank

Summer

Since most of the surveys were conducted during the summer months the
results obtained during this season will be discussed first. The total catch per tow
of haddock and the catch per tow by ages for ail of Georges Bank for each of the three
survey years are presented in figure 2 and table A-1 . The total catch per tow varied
markedly during the 3 years, with a maximum of 134 in 1949 and a minimum of 37 in
1948 . These differences in the total catch per tow were due mainly to differences in
numbers of younger fish (0 to 3-year-olds) or more specifically to the abundance of
the 1948 year class >

TTie zero -ring group was not adequately sampled for it will be noted that the
abundance of one-year-old haddock in 1949 and 1950 was greater than the abundance
of zero -ring fish m the respective fsreceding year. The catch per tow of zero-^ing
fish does, however, serve as an indication of year class strength as seen in the catch -
per -tow data of subsequent years. Part of this inadequate sampling may be attributed
to the escape of tSie smallest haddock through the 1-1/2 -inch Imer. However, there
is evidence that some Georges Bank haddock inhabit during their first year of life areas
outside ot Georges Bank and thus outside the area sampled.

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Althou^ only Georges Bank was surveyed consistently with tl^e Albatross III,
occasional trips were made to adjacent areas (Subareas E, F, and Q in area XXII
and area XXIII) and in these locations the concentration of zero-ring haddock was
sometimes greater than that on Georges Bank. The abundance of zero-iing haddock
in all locations sampled is shown in figure 3 .

It appears likely tliat the Georges Bank stock of haddock may be dependent,
at least in part, upon the immigration of immature fish from off the bank proper, and
that the St very young migrants may have been spawned either bn the bank or in the
GuLf of Maine .

Some of the 1948 data are inconsistent with the 1949 and 1950 records. For
instance, the abundance figures for 2, 5,, 7, and 9-year-old fish in 1949 were greater
than those for 1, 4, 6, and 8-year-old fish in 1948. It is our opinion that the sampling
technique was not so good in 1948 as ia other years. Another iindication of this is the
lower number of species per tow and the greater number of tows with 0, 1, and 2
species in that year (Taylor 1953). The reason for this poorer sampling in 1948 is
not immediately apparent for, as seen in table 1, the number of tows by subarea,
depth, and bottom type were consistent with those of other years . One way in which
'the 1948 sampling technique differed from that of 1949 and 1950 was in the time ire-
quired to cover the designated area. In 1948, 97 days were required to sample the
area, while in 1949 and 1950, 23 and 53 days, respectively, were needed. Also, dur-,
ing the 1948 cruises towing speeds varied considerably which possibly contributed to
the sampling error. Because of this discrepancy oaly the If 49 and 1950 data were used
in estimating mortality rates and in determining mean values .

Since the catch per unit of effort varied markedly from year to; year, the age ,
composition was expressed as percentages of the total catch per tow in order to give
a clearer picture of the differences in the age composition of the catch during the three
years. These percentages are shown Ih figure 4.

In 1948, more than 90 percent of the catch was made up of 0-3 -year-old fish,
with 2 -year -old fish predominant (37pere«it)o In 1949, over 90 percent of the catch
consisted of 1 throu^ 3 -year -old fish with 1 -year -old fish predominant (75 percent) .
The percentage of zero-ring fish in 1949 was negligible. In 1950, 89 percent of the
catch were in the 0 throu^ 2 -year age group with 2 -year-old fish predominating
(49 percent). The relative hig^ percentage, as well as actual numbers, of zero -ring
fish in 1950 indicates a successful 1950 year class, and the low percentage and numbers
of 1-year-old fish, indicates the weakness of the 1949 year class. TTie slightly higgler
percentage of 5-year-old fish, which were found principally in subareas G and H in
1950, is not readily explainable from the age composition of the 1948 and 1949 catches.

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From the catch per tow and percentage age composition data (figs. 2 and 4)
it is seen that 1946, 1948, and 1950 were years m which spawning was relatively
successful. The effect that these years of successful spawning have on the catches
of the following years is exemplified by the effect that the 1948 year class had on
the catch per tow data for 1949 and 1950. The success of the 1948 and 1950 year
classes has been further substantiated by the landing of the commercial fleet (Schuck
and Clark, 1950). These two year classes have been the mainstays of the haddock
fishery during recent years. It is thus evident that census surveys such asflhose
conducted with the Albatross III during 1948 to 1950 can be very useful in predicting
the commercial catch several years in advance.

Moa:tality rates can also be estimated from surveys of this kind. However,
it must be emphasized that these rates are based on an extremely limited sample and
as pointed out by Rounsefell and Everhart (p . 15, par. L-9, 1953), it is unsafe to draw
any conclusions from them without further verification. In table 2 are presented the
mortalities in percentage for various age fish, based on the catch per tow data for
1949 and 1950.

The indicated mortality rate is higher in l-to-4-year-old fish than in 5-to-8-
year-old fish. Zero-ring fish were not included because of inadequate sampling, but
natural mortality probably makes up a large proportion of the total mortality of these
recently spawned fish which occur generally in areas outside those fished extensively
by the commercial fleet and are also not retained by the commercial-size gear. The
commercial fleet begin catching haddock during their second year (one -year -olds)
and one and two-year-old fish make up the bulk of the fish discarded at sea. Thus
fishing mortality appears to be an important factor in the depletion of even these
younger fish. Young fish occur in large concentrations and in the same locations as
the older fish and it is this combination of availability and large numbers that most
likely accounts for their high mortality rates .

Commercial catch records indicate that older haddock (5 years) tend to move
to deeper water off the northern edge of Georges Bank where fishing intensity is much
less, which fact might explain the decrease in mortality rate of these fish. This
movement of older fish into deeper water will be discussed further when the distribu-
tion in relation to depth zones is considered.

Althou^ these mortality rates are based on only 2 -years data, and subject
to numerous errors, indications are that of a sample of 100 one-year-old fish
only 5 of these survive to be 3 -year olds. Having an accurate knowledge of these
mortality rates and their relation to changes in fishing effort, it should be possible
by using a similar sampling technique to predict the numbers of marketable fish
available in future years from a sample of one-year-old fish. An even better method

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for making early predictions would be to devise a means of adequately sampling
the zero -ring haddock which are found concentrated in definite areas completely
separated from other year classes and not subject to fluctuating fishing intensity.

Spring

A survey was made during this season only in 1950 and only in subareas H, J,
M, and N. The distribution of tows in each subarea, depth zone and bottom type was
the same as that in the summer months (table 1). The catch per tow of each age and
the percentage age composition are presented in table 3 . The predominance in the
catch of the 1948 year class (2-year-olds) is again demonstrated.

Table 2 . - -Mortality rates (percent) in various age groups

Item

Summer of 1949
age group

1

2 3 1 4

5

6

7

Catch per tow

Catch per tow

Mortality rate
(percent)

100t3

10.4 12.5 6.7

2.1

0.73

0.38

Summer of 1950
age group

2

3 4 1 5

6

7

8

30.3
70.00

1.8 1.6 2.2
82.7 87.2 67.2

0.8
61.9

0.43
41.1

0.15
60.5

Table 3 . - - Catch per tow and percentage of age composition in various
age groups

Item

Spring of 1950
age group

1

2 |3 4 5

6 7 8 1 9-1- Total

Catch per tow
Percentage

13.11 64.84 5.93 4.51 3.64
13.90 68.73 6.29 4.78 3.86

1.22 0.63 0.20 0.26 94.34
1.28 0.67 0.21 0.28 100.00

12

As no records are available for this season for other yeiirs, no direct
comparison by season can be made. However, because the mortality rates based
on 1949 and 1950 data for July and August appear considerably higher than rates
based on commercial landings (Schuck and Taylor, in press) and show a decrease
in mortality with increasing age while the commercial data show an increase with
increasing age, it is of interest to estimate mortalities on the basis of the spring
of 1950 and summer of 1949 data. If fishing intensity were constant, numerical
mortality based on this 9 -month period should be considerably lower because of the
shorter time lapse between successive samplings of the populations and should serve
as a check on reliability. Only subareas H, J, M, and N could be used for the com-
parison of mortalities. The catch per tow for these subareas for 1949 and 1950
(summer), and 1^50 (spring), and the calculated mortalities are given in table 4.

Table 4. --Comparison of -mortalities based on catch per tow data
for summer of 1949 and 1950, and spring of 1950 in
subareas H, J, M. and N

Item

Slimmer of 1949
Age group

1

2

3

4

5

6

7

Catch per tow

Catch per tow

Catch per tow

Summer, 1949

to
Spring, 1950

Summer 1949

to
Summer 1950

141.0

15.0

18.4

7.3

2.0

0.6

0.3

Spring of 1950
Age group

2

3

4

5

6

7

8

64.8

5.9

4.5

3.7

1.2

0.6

0.2

Summer of 1950
Age group

2

3

4

5

6

7

8

46.2

2.5

2.2

2.8

1.0

0.5

0.16

51.2
67.2

59.8
83.5

Mortality (p
75.5 49.7

87.8 61.0

lercent)
38.5

53.5

0
23.8

37.5
50.0

13

The numerical mortalities are indeed consistently lower for the shorter time
lapse. That spring and summer distributional differences do not invalidate this com-
parison is evidenced by the fact, which will be shown in a later section, that
distributional differences of the various age groups are merely found in relation to
depth and not to subarea. Therefore, all age classes were uniformly sampled as
regards the four subareas under consideration .

Abundance and Age Composition in Individual Subareas

Summer

The catch per tow (total and by ages) and the percentage age composition by
subarea for the years 1948, 1949, and 1950 and the 1949-1950 means are presented
in figures 5 and 6 and table A-2. Upon comparing the histograms for the three years,
it is apparent that poor catches in subarea M in 1948 were responsible for the dis-
crepancies previously mentioned. In 1949 and 1950 the major portion of the fish were
found in subareas J and M which was as expected from the catch records of the
commercial fleet.

In order to evaluate subareas as regards availability of fish, the mean catch
per tow for each year was assigned a value of unity. The index number was then
determined for individual subareas relative to this value . These comparisons are
presented in figure 7 .

As stated above, the catches in subareas J and M were consistently high while
the catches in other subareas fluctuated considerably from year to year with subarea
O usually having the poorest yield.

Two -year -old fish were dominant in the 1948 catches (figs. 5 and 6) and
this predominance held true for all subareas except G, N, and O. In subareas N
and O zero -ring fish made up the greater proportion of the catch, while in subarea
G, 3 -year -old fish were most plentiful. Subareas G and H were distinct in that they
were the only subareas in which an appreciable number of fish older than 4 years
were caught.

In 1949 the catch per tow was greatest in subarea M and one-year-old fish
dominated the catch in all subareas with the exception of G and J where 3 and 4-year-
old fish, respectively, prevailed. In subareas N and O no fish older than 2 years
were caught. The proportion of older fish (5 years) was greatest in subareas G and
H, although the total abundance was less than in other subareas .

14

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by subarea, Summer.

16

In 1950, the catch per tow was greatest in subareas J and M with 2 -year -old
fish making up the hulk of the total catch. Two -year -old fish dominated tJie catches
in subareas H, ], and M while zero-ring fish prevailed in subareas G, N, and O.
Subareas G and H again had the highest proportion of 5 year and older haddock and in
subareas N and O very few fish older than 2 years were cau^t.

To summarize the subarea distribution in the summer, it may be stated that:

1 . In all three years the catches of haddock 5 years and older were
greater in subareas G and H than over the rest of the bank . This fact is more
graphically illustrated in the following table (taJale 5) giving tJie catch per tow and
percentage of 5 year and older haddock by subarea.

2. Subareas J and M had consistently the greatest conceeai^ation of
haddock, but the greater proportion of these fish were 1 -to -3 -year -olds.

3 . in subareas N and O the catches were made up' principally of zero-
ring and one-year-old fish with older fish seldom observed.

Tables. — Catch per tow trodperccotage age composition of 5-year and
older haddock by subarea

Subarea

Item

1948 1949 1950 1950 Average 1949-

Summer Summer Summer Spring 1950 Summer

G

Catch per tow
Age composition

' 4.88
15.7

9.20
33.0

5.09
15.5

No sample

7.32
24.3

H

Catch per tow
Age composition

3.96
12.3

3.71
12.4

11.37
21.5

12.49
30.0

7.62
18.3

J

Catch per tow
Age composition

1.56
1.4

4.35
2.0

5.98
4.6

4.23
6.2

5.27
3,1

M

Catch per tow
Age composition

0.46
8.2

5.82
1.4

1.08
1.0

5.71
5.4

3.55
1.3

N

Catch per tow
Age compo^tioiL

0.31
0.7

0

1.19
2.4

2.15
1.6

0.56
0.9

Catch per tow 0.08 0

Age compositiori 0.09 0

0' No sample 0

0 -- 0

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Spring

The catch per tow (total and by ages) and the percentage age composition by
subarea for 1950 (spring is shown in figure 8 and table A-2). The total catch per tow
was greatest in subarea N, showing a shift from the summer distribution. Two-year-
old fish dominated the catch as in the summer of 1950.

Because these subdivisions of the bank are based on commercial fishing concen-
trations and thus purely artificial boundaries, discussion of the distribution of
different age fish will now be considered in the light of certain ecological conditions .

Abundance and Age Composition as Related to Depth

As stated in the introduction, sampling at census stations was stratified by 3
depth zones: 0-30, 31-60, and 61-150 fathoms. A preliminary analysis, however^
revealed that the catch per tow dropped markedly in depths between 60 and 90 fathoms.
For this reason the third depth zone was further divided into 2 zones. Thus, there
are four zones used in the study of the relation of the distribution of haddock with
depth. They are as follows:

Depth zones Depth range in fathoms
I 0-30

n 31-60

III 61-90

IV 91-150

Summer

Figure 9 and table A -3 show the total and relative abundance of the different ages
in the four depth zones for the years 1948, 1949, and 1950, as well as the 1949-1950
means. In all three years depth zone II yielded the most haddock followed in descend-
ing order by depth zones I, IV, and III The only exception was in 1948 when depth
zone rv yielded a slightly greater catch per tow than depth zone I . In every year of
the survey the zone between 61 and 90 fathoms showed a very much lower concentra-
tion of haddock than depths either above or below it.

The age composition of the catch also varies with depth. This is evident from
figure 9, but is brought out more clearly in figure 10 where the catch per tow of each
age is expressed as a percentage rather than numerically. It is clearly seen that the
percentage of older fish increases with increasing depth from zone 1 and IV. This is
best illustrated by the 1949-1950 means.

20

When the catch per tow is expresseti m terms of weight rather than numbers we
find chat a conoiderable portion of the haddock stock occurred in deep water, at least
during the times of these surveys .

To convert numbers of haddock to pounds the factors in table 6 were used.

Table 6. --Age-weight relationship of haddock in summer

Age of fish 0 12 3 4 5 6 7

Mean weight 0.30 0.93 1.71 2.60 3.43 4.12 4.56 5.71

6.48

9+

7.64

These factors are average weights of each age during summer months . For the
purpose of sradying the differential age distribution with depth the fish were divided
into two groups according to age . The 4 -year -olds and younger fish were placed in
the first group while those more than 4-years old were placed in the second group .
The abundance of these two age groups at the different depths is presented in table 7.

Table 7 . - -Depth distribution of young and old fish in summer

0-

■4 years

5-9-1-

■"yea.rs

Total

Depth

Numbers

Wsuirds

Numbers

Pounds

Numbers

Pounds "

zone

per tow

per tow

per tow

per tow

per tow

per tow

Year

No.

1948

I

13.15

25.28

1.57

7.50

14.72

32.78

U

64.53

91.09

0.69

3.25

64.68

94.34

III

5.61

4.66

0.47

2.35

6.08

7.01

IV

12.63

31.79

4.85

24.66

17.48

56.45

1949

I

116.34

122.78

1.87

8.65

117.61

131.43

II

232.91

297.64

3.27

14.71

236.18

312.35

m

1.09

2.82

0.38

1.82

1.47

4.64

IV

12.78

37.94

7.88

39.92

20.66

77.86

1950

I

46.99

79.14

5.10

22.73

52.09

101.87

II

94.62

112.97

1.45

6.88

96.07

119.85

lU

3.88

3.17

1.35

6.93

5.23

10.10

IV

19.62

24.81

9.70

46.60

29.32

71.41

1949-

I

78.45

99.11

3.62

16.28

82 .'(17

115.39

1950

II

163.11

200.17

2.36

10.83

165.47

211.00

III

2.54

3.01

0.87

4.41

3.41

7.42

IV

15.62

32.55

8.62

42.64

24.84

75.19

21

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Figure 9. --Total catch per tow of individual ages by

depth zone, Sunimer.

22

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Figure 10. --Percentage age composition for each depth zone,

Summer .

23

It is clear from these data that:

1. The total catch per tow (unsegregated year classes) was greatest in depth
zone 11 and least in depth zone III whether expressed as numbers or as weight. This
situation was found in each survey year .

2. The young fish (0-4 years) were most abundant in depth zone II and least
abundant in zone III whether the catch per tow be expressed in numbers or in pounds .
This situation was found in each survey year.

3 . The older fish, on the other hand, showed the greatest abundance each
year in depth zone IV when expressed in numbers or pounds per tow. In practically
all cases the zone of least abundance of older fish was depth zone IK.

4. In all years except 1948 and at all depths, the number per tow of 0-4 -year-
old fish was greater than the number per tow of 5-9+ year-old fish with the ratio
diminishing with increasing depth.

5. In all years the weight per tow of 0-4-year-old fish was much greater than
the weight per tow of 5-9+-year-old fish in depth zones I and II, practically equal in
depth zone III and less in depth zone IV.

6. In no year was the weight per tow of 5-9+-year-old haddock in depth zone IV
greater than the weight per tow of 0-4 -year-old haddock in depth zone II.

In order to determine at which depth the most valuable quantity of haddock
occurred the weight -per-tow data were further classified roughly according to
market categories. The following four groups were made:

1. 0-2-year-oid - representing haddock of unmarketable size. \J

2. 3-4-year-olds - representing mostly " scrod haddock" which bring the
lowest market price.

3 , 5-9+-year-olds - representing "large haddock" which bring the highest
market price.

4. 3-9+-year-olds - representing all marketable haddock. These fish are
sold at a mixed price depending upon the proportions of scrod and large haddock .

The average weights per tow for each of these categories at each depth are
presented in table 8 .

1/ It must be kept in mind that this division of haddock into marketable and unmarket-
able groups according to age is an approximation based on average cori'ditions during
the spring and summer seasons . The age of haddock landed varies with the season of
the year and with the relative abundance of the various year classes making up the
population in the area fished (Schuck and Clark, 1951). An unmarketable haddock is
defined as one weighing less than. 1 .5 pounds. In the average year this would include
a small proportion of 3 -year -old fish during the spring months and the majority of
the 2 -year -old fish during the summer.

24

In 1948, unmarketable haddock were most abundant in depth zone II. The weight
per tow uf "scrod haddock" v/as least m depth zone III and about evenly distributed in
the other depth zones. The greatest weight per tow of 5-9+-year old and 3-9+-year-
old haddock was in depth zone IV. The weight per tow of large haddock in depth zone
IV almost equaled the weight per tow of ail marketable haddock in depth zones I and
II, and the weight per tow of all marketable fish, both scrod and large, was almost
double that of other depths .

In 1949 the greatest weight per tow of unmarketable, marketable, and scrod
haddock occurred in depth zone II. The greatest weight per tow of large haddock was
obtained in depth zone IV . Considering that the market price ratio of large haddock
to scrod haddock is roughly 3/2, the value of the catch in depth zone IV was consider-
ably greater than that of the other zones .

Table 8 . - -Weights per tow of four age groups of haddock in four depth zones
during summer of 1948, 1949, and 1950

(In pounds)

Summer 1948, Summer 1949,. Summer 1950,

Depth zone, in age group in age group in age group

(in fathoms) 0-2 3-4 5-9+ 3-94- 0-2 S-4'5-9i- 3-^ 0-2 3-4 5-9+ 3-9+

0-30 6'. 14 20.58 7.50 28.08 105.04 17.8X8.64 26.51 64.84 14.24 22.73 36.97

31-60 65.27 24.78 3.23 28.01201.04 73.96 14.7188.67 K)5.QI 7.94 6.88 14.82

61-90 1.80 2.86 2.36 5.22 0.61 2.22 l.»3 4.05 2.13 1.04 6.94 7.98

91-150 2.28 29.49 24.65 54.14 2.16 35.79 39.93 75.72 7.94 16.88 46.65 63.53

In 1950 the separation of the various age categories of haddock was, even more
marked. The greatest weight per tow of unmarketable haddock was again obtained in
depth zone II, while the weight per tow of 3-4, 5-9+ and 3-9+-year-old haddock was
greatest in depth zone IV- TTie weight per tow of large haddock alone in depth zone IV
was more than three times that of all marketable haddock in depth zone II.

It appears, then, that as far as the haddock fishery is concerned, it would have
been both more profitable to the fishermen and more expedient from a conservation
standpoint to have fished in depths greater than 90 fathoms during this period.

25

The effort of the commercial fleet during this period was concentrated in water
shoaler than 60 fathoms (fig. 17). The reason the fishermen restricted their efforts
to the shoaler water when there were available more pounds of large haddock in deep
water is not immediately apparent. Perhaps they were unaware of the presence of
these fish. If in fishing operations they gradually extended their drags from the pro-
ductive depth zone II into deeper water they would be moving into the 61-90 fathom
deep zone which was the least productive zone. It is possible, then, that depth zone
in represented a barrier to the deeper, more productive areas .

Furthermore, the fact that this depth distribution is seasonal (see page 31)
could also explain why the fishermen may not be aware of it.

The greater expense of fishing in deeper water must also be taken into considera-
tion. Setting the gear in deep water is more difficult and hauling requires much more
time. There is also the danger of tearing the net on the rough bottom in the lesser
known depths .

The presence of a greater number of trash fish or a smaller number of otlier
marketable species, however, does not appear to be a justifiable reason for avoiding
deeper water as a further analysis of the Albatross III census data revealed that the
proportions of marketable and unmarketable fish 2/ of other species did not fluctuate
appreciably with depth.

The above study of depth relations is based on records for the bank as a whole.
In the preceding section dealing with the variations of the catch in different subareas
it was noted that subareas G and H consistently had the highest catch per tow and the
highest percentage of older haddock (5 years). Correlating this with the fact that
older haddock were more abundant in deeper water, it is interesting to note from
fig. 11 and table 9 that the subareas yielding the greatest concentration of older
haddock are the ones having the greatest area of water deeper than 90 fathoms.

2J Whether a fish is marketable or not depends largely upon the amounts caught,
the purpose of the trip, and where the fish are to be sold. For example, vessels
fishing out of Boston concentrate their efforts on haddock and in the Georges Bank
area while vessels fishing out of Gloucester fish primarily for redfish and in the
Gulf of Maine. The Boston boats discard redfish, which are found only in depth zone
iV, for there is little market for them in Boston, while the Gloucester fleet finds
a markel: for both redfish and haddock .

26

27

Table 9 . - -Areal extent of each depth zone in each statistical subarea
of Georges Bank (area in square miles)

Depth zone Statistical subarea
(in fathoms)

G H T M N O Total

0-30 fms.

964

1,211

405

795

1,050

1,980

6,405

31-60 fms.

578

506

851

2,(744

2, 160

2,520

8,659

61-90 fms.

788

518

158

i99

491

278

2,432

91-150 fms.

1,215

1,249

701

83

218

60

3,526

Total 3,545 3,484 2,115 3,121 3.919 4,838 21,012

In subareas,M, N, and O the area of water greater than 90 fathoms was
negligible. Therefore, these subareas were omitted in the study of the regional
aspects of the depth -age relationship.

The 1949 and 1950 data were averaged in terms of weight per tow by depth zone
for the three other subareas and are presented in table 10. ^'

Comparing table 8 with table 10 it is seen that the weight per tow of each age
group in each of the three subareas was in general similar to that for the whole bank .
The weight per tow of large haddock (5-9-1- years) was greatest and the weight per tow
of discards (0-2 years) was least in depth zone IV in each subarea, except in subarea
H where the weight per tow of 5-9+-year-oid haddock was slightly less in depth zone
IV than in depth zone I .

Regarding the sharp and consistently lower catch per tow of all ages of haddock
in depth zone III, several causes could be postulated. The area hounded by the 60
and 90 fathom contour lines consists for the most part of a narrow band along the
edge of the bank representing to the north a transition zone between the shallow bank
water and the deeper water of the Gulf of Maine, and to the south and east a transition
between the shallow bank water and deep water off the continental shelf. Because the
graidient between tlie 60 and 90 fathom lines is greater than that above or below this
zone, it was thougjit that possibly the efficiency of the otter trawl was affected by

ZJ The catch per tow by depth zones for individual subajseas are presented in
tables A-4, A-5, A-6, A-7, and A -8 in the Appendix.

28

the slope.. However, no average slope greater ihan 2 degrees was found to exist
between contour lines . Furthermore, occasionally large catches of other species
of fish have been made in this depth zone showing that if the haddock are in this depth
zone they can be caught with the gear used.

The only other factor which appears to differentiate this zone from the shallow-
er bank water and the deeper Guif of Maine and oceanic water is the character of the
bottom sediments. The bottom sediment distribution and its possible relationship
to the distribution of haddock will be discussed in a later section.

Table 10 . - -Mean weight per tow by depth zones for subareas G, H,
and J, summer, 1949-1950 average

Subarea

G

Depth zone
No.

Age group

I

U
III
IV

0-2

3-4

5-9-1-

3-^

24.42

11.52

3.44

6-86

63.71
2.38
4.28

27.86

32.59
1.71
7.32

48.92

96.10

4.09

11.60

76.78

Total

120.52
15.61
15.04
83.64

H

I

n
III

IV

96.50

23.17

3.19

1.06

34.10
6.23
1.92

21.33

55.05

9.54

11.98

46.21

89.15
15.77
13.90
67.54

184.65

35 . 95
17.09
68.60

I

II
III
IV

233.50

274.94

0.90

5.21

24.57

227.16

0.03

44.67

3.24

]6."U
15.69
36.79

27.81

224 . 06

15.72

81.46

261.31

^i9.00

16.62

86.67

Spring

Figure 12 shows the abundance in terms of numbers" and percentages of the
various age fish in the four depth zones during the spring of 1950,

At this season the total abundance of haddock decreased with increasing depth
with 2 -year-old fish dominating the catches in depth zones 1 and II and 3 -year-old
fish dominating the catches in depth zones III and IV. Although, as mentioned pre-
viously, these figures are based on a limited coverage of the bank, it is seen that

29

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T)

^

J3

4->

u

!h

(i;

a

IH

X!

.a

r>

4-1

rt

O

0)
S-l

MOl U3d HSId dO SbdQNDN

NOlilSOdlAlOD 30V lH30H3d

30

during this season there was no longer a greater proportion of older haddock
(5-+years) in deeper water. The catch per tow in depth zone III, which during the
summer months was negligible, was now considerably greater than that in depth zone
IV. In general, there appeared to be less segregation of age groups, although the
majority of younger fish (1-3 years) were found in depths less than 60 fathoms. The
age composition by depths is more clearly shown in the percentage age composition
of the total catch. The greatest percentage of older fish (5t-years) occurred in tows
made in depth zone III.

To convert numbers of haddock to pounds of haddock during this season the
factors in table 11 were used. From these factors-the weight per tow was deter-
mined for the four age groups as was done with the summer data. The weight and
catch per tow for these four age groups are shown in table 12.

Table 11.- -Age - weight relationship of haddock in spring

Table 12.. --Age group distribution in the four depth zones

(spring 1950)

Depth zone
(in fathoms)

Spring (1950) age group

1-2

3-4

5-9+

3-9f

Number per tow

0-30 fms.

176.82

26.08

12.86

38.94

31-60 fms.

61.46

7.03

3.20

10.23

61 -"90 fms.

16.07

2.61

7.10

9.71

91-150 fms.

12.51

0.42

Weight

0.94
per tow

1.36

0-30 fms.

193.09

68.36

56.99

125.35

31-60 fms.

55.07

19.70

13.61

33.31

61-90 fms.

9.09

7.69

30.20

37.89

91-150 fms.

7.92

1.21

4.60

5.81

31

The depth distribution during the spring was markedly different from the
distribution during the summer months. The catch per tow and weights per tow of
unmarketable fish (1-2 years) and scrod (3-4 yeais) decreased with increasing depth.
The catch per tow of all marketable haddock (3-9-H years) decreased with increasing
depth, but was practically uniform between 31 and 90 fathoms. The weight per tow
of all marketable haddock, however, was slightly greater in depth zone III than in depth
zone 11. The catch per tow and weight per tow of large haddock (5-9+ years) was
greatest in depth zone I, followed in descending order by depth zones III, II, and IV .
Depth zone IV, where in summer the greatest concentration of large haddock were
found, was the least productive area for all age groups .

It appears then that at this season it would have been most profitable to fish
in shoal water (0-30 fathoms), but also at this depth the greatest destruction of im-
mature fish would occur. From the conservation st;andpoint; depth zone III would be
the most desirable fishing area. However, a m.uch more thorough coverage of the
bank at this season is needed to substantiate tJiese conclusions .

This inshore movement of older fish during the spring is evidenced in the land-
ings of the commercial fleet which show a marked increase in the percentage of older
haddock at this season . Such a movement is associated with spawning activity and
has also been found to occur in European stocks of haddock (Thompson 1929b).

Although there is a slight variation from year to year; the spawning season
for Georges Bank haddock is mainly from February through April (Bigelow and Welsh,
1942, Walford 1938). These spawning dates are further substantiated by the fact
that large numbers of ripe fish were taken during the spring cruise of the Albatross III.
Thus the above data for the spring represents conditions existing during the spawning
season .

The age at maturity (age at which spawning occurs) varies considerably with
location. Bigelow and Welsh (1925) give 4-5 years as the age at maturity for haddock
in the Gulf of Maine area near Cape Ann . More recent data obtained on the Albatross
in and commercial vessels during March of 1949 and 1950 indicate that the age at
maturity for Georges Bank haddock is considerably earlier than this and is different
for males and females. The following table (table 13) gives the age at maturity for
haddock on Georges Bank, Browns Bank, the Newfoundland Banks, and the North Sea.

The age at maturity of Georges Barik haddock is very similar to that for the
Nortli Sea, while Bigelow' s figures for the Gulf of Maine coincide with Albatross III
observations on Browns Bank and with Thompson's figures for Newfoundland and
Iceland, the haddock from the latter area maturing at 4-6 years (Thompson 1929A).z.'

4/ There exists slight evidence to the effect that the age at first maturity varies
between year classes and that first maturity ofccurs in the larger fish of a certain
year class. (Hansen 1949).

32

Table 13 . - -Age at maturity for haddock in various geographic areas

Haddock

Percentage of mature fish at age--

Location

2

3

4

5

6

Males
Females

40
0

98

77

100
100

-_

--

Georges Bank

Males
Females

0
0

0
0

100
60

100
100

--

Browns Bank

Males
Females

60 ■
10

95

75

99
95

100
99

100
100

North Sea,
(Raitt 193 6 A)

Males &
Females

0

15.5

44.5

95.0

100

Newfoundland
(Thompson 1939)

The division of haddock into 1-2 year and 3-9+ year age groups roughly separates
these haddock into immature and mature or spawning fish. Thus the age-depth dis-
tribution found on the basis of this grouping results from a spawning migration.

It may be stated, then, that the mature haddock seek shoaler water during the
spawning season than during the summer months. That depth is a factor of prime
importance in the determination of spawning location is well known and the depth
limits of spawning are similar for the various banks. Bigelow and Welsh (1929) state
that the important spawning grounds in the Gulf of Maine are all shoaler than 75
fathoms, with 15 to 20 fathoms as the upper limit and 100 fathoms as the lower limit
of any considerable spawning. They also note that no haddock spawn m the deep
basin of the Gulf of Maine (depth zone IV) . Schmidt (1909) and Raitt (1936), using
data based on egg distribMion, give 27-109 fathoms as the depth range of spawning
for European haddock. Thompson (1929A) from observations on egg distriijufion
gives 44-82 fathoms as the range of spawning depth of Icelandic haddock. 'Needier
(1930) from information based onflie commercial catch, states that in early spring
haddock are caught m abundance in water less than 25 fathoms, and as summer
proceeds these fish withdraw to somewhat deeper water. Thompson (1929B)
demonstrated that North Sea haddock congregate into spawning and feeding concentra-
tions during the spring and summer months and the depth distribution of these two
concentrations is seen to be similar to the spring and summer depth distribution
observed on Georges Bank.

It is apparent then that it is a spawning migration to shoaler water that is the
cause of the change in the depth distribution of haddock during the spring. TTie depth
distribution of Georges Bank haddock during both spring and summer is similar to

33

thai of haddock in other regiOub, especially to that of the North Sea. The observa-
tion that older fish generally seek deeper water and appear to migrate more than
younger fish is in agreement with fir.dings in other areas (Thompson 1943).

Abundance and Age Composition as Related to Bottom Type

" During Albatross III cruises more than 250 bottom samples were obtained by
use of "scoop-fish" bottom sampler attached to the nose of a bathythermograph.
This sampler worked successfully, obtaining approximately a 50 -gram sample over
mud,, sand, and gravel bottoms, while over harder bottoms only chips were obtained.
The bottom samples thus taken were classified according to the four size categories
given m the Hydrographic Manual (Adams 1942).

When these data were plotted and lines of demarcation drawn, it became
apparent that due to the insufficient number of samples in certain areas and the in-
ability of the gear used to obtain a reliable sample of particles larger than 6.0 mm.
that the following consolidation of the data was advisable;

Sediment Description

Sand Sand and stony sediments with particle

diameters greater than 0.1 mm.

Mud Mud and sand-mud sediments with

particle diameters mostly less than 0. 1 mm.

This consolidation was verified by the fact that the distribution of haddock was
similar over sand and stony bottoms and over mud and sand-mud bottoms . A chart
(fig. 13) was prepared according to this classification of Albatross lU samples and
to data given m Coast and Geodetic Survey Charts 1106A and 1107A.

Summer

Figure 14 and table A-3 show the total and the relative abundance of the differ-
ent ages of haddock over sand and mud for the years 1948, 1949, 1950, and the 1949-
1950 means. 5/ The total catch per tow was consistently greater over sand than over
mud bottoms and this greater abundance was in large part due to the greater numbers
of younger fish.

In table 14 the catch per tow and wei^t per tow data by bottom type is grouped
into unmarketable haddock, scrod, large haddock, and total marketable haddock, as
was done with the catch by depth zones.

5/ The catch per tow by bottom type for the individual subareas are tabulated in
tables A-4, A-5, A-6, A-7, A-8, and A -9 in the appendix.

34

35

Table 14. --Age group distribution by bottom type in summer

Year

Bottom type 0-2

Age group

3-4

5-9+

3-9+

Numbers per tow

1948

Sand

37.61

Mud

1.83

1949

Sand

137.88

Mud

38.39

1950

Sand

84.80

Mud

15.71

1949-

Sand

105.44

1950 Mean

Mud

26.5^

1948

Sand

44.05

Mud

1.63

1949

Sand

138.38

Mud

39.68

1950

Sand

110.11

Mud

14.18

1949-

Sand

113.45

1950 Mean

Mud

25.36

8.51

1.04

9.55

7.70

3.41

11.11

23.95

3.33

27.28

4.89

4.46

9.35

4.15

3.71

7.86

1.56

3.69

5.25

14.27

3.50

17.77

3.15

4.05
Pounds per tow

7.20

23.24

4.97

28.21

20.94

17.35

38.29

68.34

15.62

83.96

15.76

22.26

38.02

12.38

17.12

29.50

4.83

17.95

22.78

40.98

16.26

57.24

10.05

19.97

30.02

This grouping shows that the catch per tow and weight per tow of unmarketable
haddock and scrod was greatest over sand. The catch per tow and weight per tow of
all marketable haddock (3-9+ years) was greatest over sand except in 1948. The
catch per tow and weight per tow of older haddock (5-9+ years) was with one excep-
tion slightly greater over mud than over sand bottoms . Although older haddock
occurred in greater numbers over mud than over sand, the separation is not as
marked as that corresponding to depth .

In order to determine whether depth or bottom type was the controlling factor
in the distribution of older haddock, an analysis of variance was made on the abund-
ance data shown in table 15.

36

o o

Z ID

IT <T>

Q. —
V)

UJ
>

<

O

in

I

o
in

a:

15
CO

0>

'J-

0>

CO

4

o

-f

o

o

o

CVJ

o
o

o

CO

o

o

o o

CvJ

<

1

o

o

CVJ

0)

&

E
o

4-'

>.

CO

P
bO
n)

>.
J3

n

bO

ca

I— I

■3 ^

•a o.
d CO

O 0)
0) P

a 5
o

CD
U

■g

o

M
0)

n.

o

QNVS

ani/\i

MOi y3d Hsid do saaai/\inN

37

Table 15. --Catch per tow of 5-9-* vear-oid haddock by depth and bottom
type during the summer of 1948, 1949, and 1950

Year

Bottom
type

I

Depth zones

n m

IV

0-30 fms.

31-60 fms

61 -90 fms.

91-150 fms.

1948

Sand
Mud

2.03
0

0.80

0

0.80
0.06

0.68

7.14

1949

Sand
Mud

1.92
0

10.48
0

0.55
0.29

5.22
9.41

1950

Sand
Mud

5.92
2.23

1.71
0

1.38
1.32

11.47,
8.27

The variance ratio values were as follows:

Difference between years. F = 1 .79
Difference between depths. F = 5.51
Difference between bottoms. F -1.01

(not significant) .
(significant),
(not significant) .

Thus it is seen that the summer distribution of older haddock was consistent
during the three years, and that depth rather than bottom type was the controlling
factor in this distribution. This is as expected for the only locations in which rela-
tively large numbers of older haddock were caught over mud bottom were locations
in which tJie depth was greater than 90 fathoms (subareas G and H).

It appears, however, that the character of the bottom sediments does serve to
differentiate the 61-90 fathom depth zone from the shallower bank water and the
deeper Gulf of Maine and oceanic water. More detailed analyses by Stetson (1938)
and Northrop (1951) show that there is a certain uniformity in the arrangement of
bottom sediments of the continental shelf when they are considered by regions .
Profile lines from the glaciated section (New England and north), irrespective of
slope, have certain characteristics in common They all start with a zone of relatively
fine sand near shore, followed by a belt of coarse sands and gravel, which in turn are
succeeded by a zone of sand and gravel plus varying amounts of silts and clays lying
on the middle and outer parts of the shelf. Lines crossing the break in the continental
slope show a definite coarsening of texture there. All the traverses show a remarkable
correspondence in the depth of water at which these zones occur, which is obviously
the controlling factor as the lines are of varying length. Consequently, on lines from
the Gulf of Maine where deep water is soon reached, the succession of zones is

38

necessarily compresbed into a few miles. Over Georges Bank, which cdn be
considered as an extension of the continental shelf, the regional distribution is
similar to that of other sections of the shelf, having a like arrangement of bottom

sediments in which depth is the controlling factor . Althou^ the zonation over the
bank has a similar sequence and depth limitations, the width of certain zones is
greatly extended.

Figure 15 represents diagramatically typical profiles across various sections
of the continental shelf and Georges Bank .

Apparently then the main factor differentiating the 61-90 fathom depth zone
from the others is the lack of silt in the bottom sediments . Although obviously the
silt in itself is not the direct cause for the scarcity of haddock, it is an indication of
stronger current action . Such current action not only prevents the deposition of fine
bottom sediments, but would also prevent the accumulation of detritus which serves
directly or indirectly as food for the haddock Considering that the search for food ,
other than at periods of spawning, is the primary cause for the movements of bottom
living fish, this could be a possible explanation for the scarcity of haddock in depth
zone III during the summer months .

Spring

From figure 14 it is seen that during the spring of 1950 only 1 -year-old fish
were caught over mud bottom . The catch per tow and weight per tow data when
grouped into unmarketable, scrod, marketable, and large haddock as shown m table 16
is again comparable to the depth distribution during this season (see table 12). The
majority of the fish were concentrated in shoaler water and were consequently found
over sand bottom .

A relatively high concentration of older haddock were found in depth zone 111
during tJhe spring while in summer there was a scarcity of haddock in this region,
theoretically accounted for by the lack of food at this depth. This reasoning still
appears valid for there exists good evidence that haddock cease feeding during the
spawning season. (Vladykov and Homans, 1935; Bigelow and Welsh, 1925; Needier
1930)

Comparison of Census and Commercial Data

In order to verify the age distribution of haddock as determined from the census
data, a comparison was made with the catch of the commercial fleet on Georges Bank
during July and August, 1949 and 1950, and April 1950. The method used in analyzing
the commercial catch was as follows:

39

2_- o
ca°far-\

^ a

/ ' y

"■""" — ^

O /' 1
<o /< 1/

\
\

\
)

\
1

\

,\ -x

\

\

1

\ \
\ \
\ o
^ Of

o

"'\

;:-^i

%c

f ' '

01

^\

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^w

O

tn

e

o

4->

o

(U

Ul

en

-1

M

o

c

&

>

CO

4-)

V-l

M

o

4-(

(1)

s

F

T3

^

C

<u
tn

a

0)

H

J=

o

4->
4~)
O

X3

2

a

**-!

(U

n

c

c
o

■a

4^

a
o

^

u

^

l-l

3>

o

lO

SWOHIVJ NI Hidaa

40

1 . The weigh: of scrod and haddock and the effort in terms of days fished by
subarea were obtained for the periods of concern from the catch records of the commer-
cial fleet.

2 . From the average weight of scrod and haddock during these periods these
weights were converted to numbers of scrod and haddock.

3 These numbers of scrod and haddock were then allocated to their respective
age groups from age readings of scale samples obtained from the landings of a random
selection of boats.

4. The catch per day of each age was computed as percentages of the total
catch in order to facilitate comparison with the data for census cruises.

Table 16 . - -Age group distribution of haddock over bottom during the
spring

Type of bottom

Sand
Mud

Sand
Mud

1-2

87.39
13.85

88.32
6.93

3-4

32.18
0

Age group

5-9+

3-9+

Number per tow
6781
0
t^eight per tow
30.26 62.44

0 0

Total

11.97

6.81

18.78

106.16

0

0
Weight per tow

0

13.85

150.76
6.93

Because the commercial fleet tended to concentrate in certain areas it was further
necessary to weight the census data according to the effort expended by the commercial
fleet and to exclude data outside the area fished by the fleet. This effort in terms of
days fished and percentage of the total days fished by subarea is given in table 17.

Table 17- -Effort of the commercial fleet in terms of days fished per

month and percentage

Date

Fishing
Effort

Subarea

Total

H

J i

M

G

0

1949

Days fished

-

139.7

44.7

11.6

-

196.0

July- Aug.

Percentage all

fishing

-

71.5

22.6

5.9

~

100.0

1950

Days fished

-

268.2

56.3

4.2

5.0

333.7

July- Aug.

Percentage all

f i shing

-

80 4

16.8

1.3

1.5

100 0

1950

Days fished

9.2

29.4

9.6

-

-

48.2

April

Percentage all
fishing

19.1

61.0

19.9

"

100. 0

41

It is seen that the commercial fleet concentrated its fishing to a very restricted
portion of the bank with the maximum effort in both summer and spring being expended
in subarea J. The weighted catch per tow and percen':age age -composition of the
census data and the catch per day and percentage age -composition of the commercial
fleet is presented in table 18 .

Table 18 . - -Comparison of age composition as determined from Albatross III
data and commercial fleet samples

Item

Age group

"otal

Catch

per tow 42.37 57.07

Percent 34.00 45.80

Catch

pertiay 2488.1 3620.6

Percent 31.8 46.3

Catch
per tow
Percent

Catch
per day
Percent

74.48
84.57

4.12
4.68

7794.9
77.7

Catch

per tow 30 . 99

Percent I 64 . 08
Percent II

995.1
9.9

5.75
11.89

Catch

per day 161.5 668,
Percent I 4.5 18
Percent II -

Albatross III - 1949 July - August

20.20 3.43 0.80 0.40

16.21 2.75 0.64 0.32

Commercial

1290.4 236.8 88.0 47.1
16.5 3.0 1.1 0.6

Albatross Ul - 1950 July

0.18
0 15

28.9
0.4
August

4.41
5.01

3.50
3.97

0.97 0.37 0.12
1.10 0.42 0.14
Commercial

720.3 345.0 100.9

7.2 3.4 1.0

Albatross III -

43.4 18.9
0.4 0.2
1950 April

5.52 3.97
11.42 8.21
47.5 34.1

1.16 0 56 0.17

2.90 1,15 0.35

10.0 4.8 1.5

Commercial

0.16
0.13

21.3
0.3

0.10
0.11

18.6
0.2

0.24
0.50
2.1

2 1203.3 923.2

4 33.4 25.5

44.2 33.9

306.4 163.4 19.3 104.7

8.5 4.5 2.3 2.9

11.3 6.0 0.7 3.9

124.61
100.0

7821.2
100.0

88.07
100.0

2242.2
100.0

48.36
100.0
100.0

3610.0
100.0
100.0

NOTE . - -Two groupings (I and II) were made of data collected In spring by the
Albatross III and by the commercial fleet to show differences and similarities in age
composition of the samples .

42

In the summer montiis only 2 -year and older haddock are tabulated. The
reason for this is that the commercial boats which used gear having approximately
a 3 -inch mesh cod end did not sample zero and one-year-old fish adequately. Fish
of this size that were retained in th.e net were discarded at sea and hence not included
in the catch statistics. During the spring months still older fish are discarded in-
cluding most of the 2 -year -olds and a portion of the 3-^ear-olds . This increase in
the culling age during the spawning season is due in part to the greater availability
of older haddock in the area fished by the commercial boats and in part to the fact
that a fish of a given age is smaller in the spring when the "haddock year" begins
than in the summer. This increase m the catch of older haddock during the spring is
evidenced by the landings of the commercial fleet over a number of years and is due
to the migration of older fish into shoaler water as shown above. Thus, in the age
group data shown in table 18 and figure 16, two groupings were made of the spring
data in order to demonstrate the differences and similarities in the age composition
as determined from commercial and census figures.

The age composition of the commercial and census data are similar during July
and August of 1949 and 1950 for all ages and during April of 1950 when only 4-year-
old and older fish are considered. The above comparison greatly attests to the reli-
ability of the census data and its value in population studies when account is taken of
the fact that these census data are based on a comparatively few completely random
sam.ples compared with that of the effort expended by the commercial fleet, which
effort is necessarily biased in that it is concentrated on certain age groups and re-
stricted areas .

Mortalities based on such a limited sampling of a population are necessarily at
best rough approximations, but it is interesting to note that the mortalities determined
from the weighted census data and commercial data for July and August of 1949 and
1950 are quite similar. These mortalities are given in table 19 and it is seen that
the mortality for all ages appear exceptionally high which lends credence to similar
figures determined from census data based on all subareas as shown in table 2 .

Mortalities determined from census data for the period of July and August of
1949 to April of 1950 were consistently lower for all ages than those determined for
the longer period of July and August of 1949 to July and August of 1950. However,
similar figures based on commercial data give negative values for 5 year and older
haddock for the 9 month period. These negative results are due largely to the
migration of older fish during the spawning season from deep-water areas little fished
by the commercial fleet into shoaler water where the greatest effort of the commercial
fleet is expended.

The average mortality rates determined from the yearly abundance data of the
commercial fleet obtained over a 20 -year period show wide fluctuations throughout the

43

00

H S 60

o ^ 40

Q.

O
O

LU
<

20

00

SUMMER

1949

2345678 9+

uj < 80 -

UJ °^ 60
Q. UJ

O

o

40

20

0

2345678 9+

950

2345678 9+

2345678 9+

SPRING
1950

Ll

2345678 9+ 45678 9 +

2346678 9+ 45678 9+-

Figure 16. --Percentage age composition of commercial and census data
during July and August 1950, and April 1950.

44

Table 19 . - -Mortality (percentage) based on commercial and weighted

census data

Source
of data

Age group

Date

2

3 4

5

6

7

1949, July & Aug.

to

1950, July & Aug.

FWS
Census

90 3

92.3 82.9

71.7

53.8

70.0

1949, July & Aug.

to Commercial

1950, July & Aug. fleet 60.0 80.1 73.3 57.4 50.7 5^.9

St. 4 90.3 80.3 66.2 30.0 57.5

1949,

July & Aug.

to

FWS

1950,

April

Census

1949,

July & Aug.

to

Commercial

1950,

April

fleet

73.1 66.8 27.7

years and in general a marked increase in the mortality of older haddock. To explain
this. It had been assumed that the older haddock were fished more intensively. The
census data, however, now show that the indicated increase in mortality with increasing
age is probably fallacious and is due to the decrease in availability with increasing age
caused by the migration of older fish to deeper, less fished regions .

From statistics obtained from commercial -catch records giving the number of
days fished in each unit area during trips which were devoted primarily to catching
haddock, it has been possible to make up concentration charts showing where the major
effort was expended duiring July and August of 1949 and 195D. The following units of
effort in terms of days fished were chosen in the construction of these charts:

Designation Number of days

fished per month
Very heavy 45-60

Heavy 30-45

Medium 15-30

Li^t 1-15

45

300+

150

-300

50

-150

10-

-50

From census data for similar periods charts were constructed showing the
distribution of i- 2, 3-4, 5-9-»-, and 3-9-1— year -old fish representing unmarketable
haddock, scrod haddock, large haddock, and all marketable haddock . The following
four units of abundance were used:

Number of fish
Designation per half hour tow

Very heavy
Heavy
Medium
Light

These charts showing the area fished by the commercial fleet and the location
of the different age groups of haddock as determined by census tows during July and
August of 1949 and 1950 are presented in figure 17. _'

In July and August 1949, the maximum effort of the commercial fleet was ex-
pended in subarea J (see figure 11) with limited fishing taking place in subareas M
and G. The distribution of the various age groups as determined from census tows
showed that large concentrations of unmarketable haddock (1-2 years) were located
in subareas J and M, but were also found in subareas N, O, and H which were outside
the area fished by the commercial fleet. The maximum concentration of scrod haddock
(3 -4 years) was found in subareas M and J, but limited numbers were also caught by
the Albatross HI in deeper water in the western side of the channel (subarea G) and
in the North East Rip (subareas H and J) . 5-9-t— year-old haddock were found in very
limited concentrations in subareas J and M with the majority of these large haddock
being located in the deep water of subareas G and H. The greatest concentration of
all marketable haddock (3-9-)- years) occurred in subareas J and M and extended con-
siderably south of the location of maximum fleet effort. Relatively large concentra-
tions of 3-9-1- year haddock were also found in deep water in subareas G, H, and J.

It is seen then that in the summer of 1949 the commercial fleet concentrated on
1-4 -year -old haddock and did not sample large areas, especially m deeper water,
where the majority of older haddock and considerable quantities of scrod were found.
This fact is substantiated by the age composition of the commercial catch during
July and August, 1949.

6/ It must be kept in mind that a marked difference exists between the two
sampling techniques involved. The commercial data is representative of the effort
per unit area for a two month period while the census data is only representative of
the age -group concentration during the short period required to sample a specific
area . Because there is bound to be some movement of these concentrations over a
two month period, the correlation between fishing effort and location is at best an
approximation .

46

OrtCHPfRTOW
(0-50
51-150
151 -JOO

^^ J ^' ""-■-...--■■""O--" ' '■''°" l\

^

TZJ

r^

o

^

3 4 YEAR OLOS

Figure 17. --Comparison of the distribution of haddock as determined from
census tows and the location fished by the commercial fleet
during July and August, 1949 and 1950.

47

In July and August 1950, the effort of tlie commercial fleet was more widely
dispersed than in 1949 with the maximum effort expended in subarea J and the southern
part of subarea G. Limited fishing also occurred in subareas M and O. The distribu-
tion of the various age groups as determined from census tows showed that the majority
of unmarketable haddock occurred in subareas J and M with limited concentrations being
located in the southern part of subarea G and in the northern limits of subarea N . No
heavy concentrations of scrod were found anywhere on the bank that year and what
limited concentrations did exist were within locations fished by the commercial fleet.
The majority of large haddock were found in deeper water in subareas G, H, and J.
The greater proportion of all marketable haddock were found in the deep water of
subareas G, H, and J with limited numbers also occurring in the shoaler waters of
subareas J, M, and N.

During the summer of 1950 the location of maximum effort of the commercial
fleet coincided with the location of 1 and 2-year-old haddock as determined from census
tows. The majority of these unmarketable haddock were 2-year -old fish of the strong
1948 year class. The concentrated effort on these fish by the commercial fleet is
evidenced by the landings for July and August 1950, which consisted of more than 75
percent 2-year-old fish. A limited and completely isolated concentration of haddock
of all ages found by the Albatross III at approximately 41° -05' North and 68° -30' West
was also discovered by the fishing fleet. Again as in 1949 the older haddock were
found principally in deeper water outside the area sampled by the commercial boats .

The concentration of the fleet in areas where smaller fish are abundant is re-
flected in the records of discarded haddock collected regularly in port by interview.
These records show that the location of the greatest destruction of unmarketable fish
during July and August of 1949 and 1950 was similar to the location of maximum fishing
effort (subarea J) . However, when this data is plotted in terms of the effort involved
(pounds per -days -fishing) the distribution of these unmarketable haddock is seen to be
quite similar to the distribution determined from the census data, being more widely
dispersed in 1950 than in 1949 and in general with the greatest concentration of these
unmarketable fish lying somewhat south of the areas of maximum effort. It is im-
possible to draw more than a general comparison between Ihe 2 sets of data because
of the inadequate coverage by the commercial fleet and the fluctuations of the age
groups making up the bulk of these discarded fish. It is noteworthy, however, that
this destruction drops markedly during the spring months as older fish are more
available and also more completely segregated from the immature fish during this
season.

It may be concluded then that during the summer of 1949 and 1950 the commer-
cial fleet concentrated their efforts in depths shoaler than 60 fathoms and consequently
on younger fish (2 to 4 -year -olds) . As stated previously it appears likely that during
these months fishing in deeper water (greater than 90 fathoms) where the majority of
older haddock were located and where younger fish occurred only in limited numbers
would have proven more profitable and more desirable from a conservation standpoint.

^ * 48

SUMMARY AND CONCLUSIONS

1 . The purpose of this study was to analyze the total and age distribution
of haddock on Georges Bank by statistical subarea, depth and bottom type, and the
variation of this distribution between seasons and years.

2. The total catch per tow of haddock for the bank as a whole varied markedly
during the 3 years and these fluctuations resulted mainly from the fluctuation in
numbers of younger fish.

3. Althou^ the sampling of zero-ring fish was not adequate due to the size of
the gear used, it did serve as an indication of year-class strength as evidenced from
subsequent samplings and the catch of the commercial fleet.

4. Although relatively large quantities of zero-ring haddock were found in
subareas N and O which long have been considered the principal nursery grounds

for the Georges Bank stock of haddock, relatively high concentrations of these recently
spawned fish were found outside of this area (subareas E, F, Q, and area XXIII). This
occurrence of large numbers cf zero -ring haddock in the Gulf of Maine and off southern
New England and Long Island coincide with the occurrence of the strong 1948 and 1950
year classes and indicates that the recruitment of the Georges Bank stock is dependent
upon fish spawned in or inhabiting, during their first year of life, areas outside the
limits of Georges Bank, as well as those fish spending their complete life cycle on the
bank proper.

5. The distribution by subarea was similar to that indicated by the commercial
catch. EXiring the summer the major portion of the haddock were found in subareas J
and M and during the spring in subarea N .

6. In all three years, not only the percentage, but also actual numbers of
older haddock (5 years and older) was greater in subareas G and H than over the rest
of the bank .

7 . EXiring the summer months the catch and weight per tow of marketable
haddock was greatest and that of unmarketable haddock least in depths greater than 90
fathoms, and thus it appears that it would have been both more profitable and expedient
to have fished at these depths .

8 . During the summer months few haddock of any age were found in the zone
bounded by the 60 and 90 fathom lines . The scarcity of fisji during this season in this
depth zone could be due to the lack of suitable food.

49

9 . The depth distribution during the spring indicated a migration of older fish
into shoaler water at this time. EXiring this season the greatest concentration of
marketable haddock occurred in water shoaier thian 60 fathoms.

10. The depth distribution of Georges Bank haddock during both spring and
summer was similar to that of haddock in other regions and is apparently due to
spawning and feeding migrations . This depth distribution was similar over various
bottom types and although greater numbers of haddock occurred over sand than over
mud bottoms, this distribution was incidental to the depth distribution.

11. The age composition of the commercial catch and of the census data when
weighted in terms of effort by subarea of the commercial fleet were very similar,
which fact further substantiates the reliability of the sampling methods .

12. Concentration charts showing tlie fishing location of the commercial fleet
during July and August and the distribution of the various age haddock as determined
from census cruises during similar periods reveal that the commercial fleet con-
centrated their efforts on younger haddock ( 2 to 4 -year olds) and principally in sub-
areas J and M and in depths between 30 and 60 fathoms and did not sample large areas
of deeper water (more than 90 fathoms) in subareas G, H, and J where the majority of
the older haddock occurred. This fact is further substantiated by the age composition
of the commercial landings which reveal that it is only during the spawning season
(spring) at which time these older haddock have moved into shoaler water that
appreciable numbers of older haddock are caught.

13 Numerical mortalities based on census data were consistent with expected
results in that they decreased umformly for all age fish with shorter time limits
between successive samplings. A marked contrast exists between these mortalities
which show a decrease in the mortality of older fish and similar figures determined
from the abundance data of the commercial catch over a considerable number of years
which show a definite increase in the mortality of older fish. This is explained by the
fact that these fish are being under sampled by the commercial fleet because of their
location (deeper water) and not by the fact that there is an increased effort expended
by the commercial fleet on these older fish with "the resulting increase in fishing
mortality.

14. The consistency of the age distribution by years, season, subareas, and
depth; the uniformity of the mortalities determined from the spring and summer data;
the accuracy of the year -class strength prediction based on the catch of zero -ring
fish which was known to be the least reliable sample; and the similarity of the age dis-
tribution determined from census and commercial data all attest to the reliability and
value of the data obtained and the methods used. It is believed that such methods with
certain adaptations for specific needs and accuracy desired would prove most valuable
in the study of migrations, year class strength, mortality and growth rates, and their
relation to ecological conditions .

50

BIBLIOGRAPHY

Adams, K. T.

1942. Hydrographic manuial. Special puiblication No. 143. Revised (1942)
edition, U. S Dept. of Comm., Coast and Geodetic Survey.

Bigelow, Henry B .

1927. Physical oceanography of the Gulf of Maine . Bull., U. S. Bur. Fish,
vol. 40(1924), part 2, pp. 511-1027, 207 figs.

Bigelow, Henry B. andW. W. Welsh.

1925. Fishes of the Gulf of Maine. Bull. U. S. Bur. Fish., vol. 40(1924),
part 1, 567 pp., 278 figs.

Fisher, R. A., and F . Yates.

1943. Statistical tables for biological, agricultural and medical research.
2nd edition, Oliver and Boyd, Ltd., Edinburgh.

Hansen, Paul M.

1949. Studies on the biology of the cod in Greenland water. Cons. Perm.
Internal. Explor. Mer., Rapp. etProc, vol. 123, pp. 1-77.

Needier, A. W. H.

1930. The migration of haddock and the interrelationship of haddock

populations m North American waters . Contr. Can. Biol. Fish.,
N. S., vol. 6, No. 10, pp. 241-313,

Northrop, J.

1951 . Ocean bottom photographs of the neritic and bathyal environment

south of Cape Cod, Massachusetts. Geol. Soc. America, Bull. 62,
pp. 1381-1388.

Petterson, Otto.

1926. Currents and fish migrations in the transition area. Cons. Perm.
Intemat. Explor. Mer., J. du Con sell, vol. 1, No. 4, pp. 322-326.

Raitt, D. S.

1936A. Stock replenishment and fishing intensity in the haddock of the North
Sea. Cons. Perm. Intemat. Explor. Mer., J. du Conseil, vol. XI,
No. 2, pp. 211-218.

1936B. The haddock stocks of the northeast Atlantic, 1916-1935.
Fisheries, Scotland, Sci . Invest. 1936, No. 1, pp. 1-31.

51

Richie, Alfred.

1937. Tho food and feeding habits of haddock (Gadus aeglefinus) in
Scotdsh waters . Fisheries, Scotland, Sci. Invest., 1937, No. 2,
pp. 1-94.

Rounsefell, George A.

1948. Development of fishery statistics m the North Atlantic. Special
Scientific Report No. 47. U.S. Fish and Wildlife Service,

pp. 1-18.

Rounsefell, G. A., & W. H Everhart.

1953. Fishery Science: Its methods and applications. John Wiley and
Sons, Inc., New York. 444 pp.

Schmidt; Jobs .

1906. The pelagic post larval stages of the Atlantic species of Gadus.
A monograph. Part 2, with 1 plate, 19 pp'.

1909 . The distribution of the pelagic fry and the spawning regions of the
gadoids in the North Atlantic from Iceland to Spain, based chiefly
on Danish in vestigaaons . Cons. Perm. Internat. Explor. Mer.,
Rapp. etProc. vol. 10, No. 4, pp. 1-229, 10 charts, 15 figs.

Schuck, H. A.

1949. Relationship of catch to changes in population size of New England
haddock. Biometrics, vol. 5, No. 3, pp. 213-231.

1951. Studies of Georges Bank haddock, part 1: Landings by pounds,
numbers, and sizes of fish. U. S. Fish and Wildlife Service,
Fish. Bull., vol. 52, No. 66, pp. 151-176.

Schuck, H. A., ard> R. Clark.

1951. An unusual haddock year on Georges Bank. U.S. Fish and Wildlife
Service, Comm. Fisheries Review, No. 285, June, 1951,

Stetson, H. C .

1938 . The sediments of the continental shelf off the eastern coast of the
United States . Pap. Phys . Oceanogr. and Meteor. 5(4),

pp. 5-48, 15 figs.

Taylor, Clyde C .

1953. The nature of variability in trawl catches. U.S. Fish and Wildlife
Service Fish. Bull. vol. 54, No. 83, pp. 145-166.

52

Thompson, H.

1922. Problems in haddock biology with special references to tlie validity

and utilization of the scale theory . I . Preliminary report .
Fisheries, Scotland Sci. Iirv^.st. 1922, No. 5, pp. 1-78.

1926. Haddock biology. II. Metabolism of haddock and other gadoid
fish in the aquarium. Fisheries. Scotland, Sci. Invest., 1926:
No. 2, pp. 1-14.

1927. Haddock biology. IV. The haddock of the northwestern North Sea.
Fisheries, Scotland, Sci. Invest., 1927, No. 3, pp. 1-20.

1929A. General features in the biology of the haddock (Gadus aeglefirms L.)
in Icelandic waters in the period 1903-1926. Cons. Perm. Internal.
Explor. Mer. Rapp. etProc . vol. 57, pp. 1-73.

1929B. Haddock biology (North Sea) Cons, Perm. Internat. Explor. Mer.
Rapp. etProc, vol. 54, pp. 135-163.

1939 . The occurrence and biological features in the biology of the haddock

of the Newfoundland area . Dept. Nat. Res. Nfld., Res. Bull. (Fish.),
No. 6, 31 pp.

1943 . A biological and economic study of cod (Gadus callarias L.) in

the Newfoundland area including Labrador . Dept. Nat. Res. Nfld.
Res. Bull. (Fish.), No. 14, 160pp.

Vladykov, V. P. andR. E. S. Homans.

1935. Do haddock feed during the spawning period? Biol. Bd. Canada,
Prog. Rep. Atlant. BioL Sta., No. 15, pp. 10-11.

Walford, L. A.

1938 . Effect of currents on tJie distribution and survival of the eggs and
larvae of haddock (Melanogrammus aeglefinus) on Georges Bank.
Bull. U. S. Bur. Fish. vol. 49, No. 29, pp. 1-73, figs. 1-50.

53

Tabls A-1. — Wuabera per tov and percenta^g aga compoBltloD ty subau-ea, area XIII

KimtMr

Subarea

Nuinbera per tow;

age composition

{In percent)

Age group

tOW8

0

1

2

3

4

5

6

7

8

9 ♦

ToUl

Suarcer 1948

23

a

Nujnbora
Percent

per tow

4.2S
13.78

1.88
6.05

3.89
12.52

13.66
43.97

2.48
7.98

2.71
8.72

0.38
2.83

0.68
2.19

0.36
1.16

0.25
0.80

31.07
100.00

20

H

Nvnnbera
Percent

per tow

0.71
2.20

3.26
10.12

U.56
45.20

7.67
23.81

2.05
6.37

1.38
4.28

0.79
2.45

0.80
2.48

0.50
1.55

0.49
1.52

32.21
100.00

22

J

Nujnbers
Percent

per tow

0.19
0.16

24.17
21.83

59.18
53.45

22.39
20.22

3.22
2.90

1.02
0.92

0.30
0.27

0.18
0.16

0.01,
0.03

0.02
0.01

U0.70
100.00

ik

«

Numbara

Percent

per tow

0.88
15.66

1.29
22.95

2.10

37.37

0.70
12.46

0.19
3.38

0.10
1.78

o.u

2.49

O.U
2.49

0.05
0.89

0.03
0.53

5.62
100.00

26

»

Numbers
Percent

per tow

23.97

57.43

8.67
20.77

8.17
19.57

0.55
1.32

0.09
0.22

0.20
0.48

0.07
0.17

0.03
0.07

0.01
0.02

0

0

41.74
100.00

27

0

Nunbera
Percent

per tow

8.30
91.51

0.05
0.55

0.37
4.08

0.10
1.10

0.17
1.87

0.06
0.66

0.01
0.11

0.01
0.11

0
0

0

0

9.07
100.00

U2

Total

Numbers
Percent

per tow

6.93

18.71

6.32

17.07

13.76
37.16

7.00
18.90

1.27
3.43

0.86
2.32

0.34
0.92

0.28
0.76

0.15
0.41

0.12
0.32

37.03
100.00

Suanner 1949

20

G

Numbers
Percent

per tow

0.05

0.18

2.19

7.86

1.65
5.92

4.48
16.08

10.29
36.93

4.86
17.44

1.97
7.07

1.06
3.81

0.62
2.23

0.69
2.48

27.86
100.00

19

H

Numbers
Percent

per tow

0.05
0.17

19.64
65.75

1.35
4.52

1.89
6.33

3.23
10.81

1.43

4.79

0.87
2.91

0.48
1.61

O.U
1.37

0.52

1.74

29.87
100.00

11

J

Numbers
Percent

per tow

0
0

64.48
29.77

51.80
23.92

71.60
33.07

24.33
11.23

3.15
1.45

0.61
0.28

0.30
0.13

O.U
0.07

0.15
0.07

216.56
100.00

21.

M

Numbers
Percent

per tow

0.3S 341.28
0.09 84.03

23.48
5.78

25.32
6.23

9.88
2.43

3.93
0.97

1.09
0.25

0.53
0.13

0.21
0.05

0.06
0.01

406.16
100.00

24

N

Numbers
Percent

per tow

0.90
1.23

72.04
98.24

0.39
0.53

0
0

0
0

0

0

0
0

0
0

0
0

0
0

73.33
100.00

a.

0

Numbers
Percent

per tow

0
0

49.81
95.04

2.60

4.96

0

0

0
0

0

0

0
0

0

0

0
0

0
0

52.41
100.00

122

Total

Numbers
Percent

per tow

0.27 100.34
0.20 74.95

10.63
7.74

12.53
9.36

6.74
5.03

2.08
1.55

0.73
0.55

0.38
0.28

0.22
0.16

0.22
0.16

133.87
100.00

Suaner 1950

17

G

Numbers
Percent

per tow

16.12
49.04

5.57
16.95

3.71
11.29

1.17
3.56

1.21
3.68

2.41
7.33

1.21
3.68

0.83
2.53

0.34
1.03

0.30
0.91

32.87
100.00

20

H

Numbers
Percent

per tow

0.20
0.38

5.79
10.97

27.77
52.64

4.05
7.68

3.58
6.79

6.95
13.17

2.64
5.00

1.17
2.22

0.34
0.64

0.27
0.51

52.76
100.00

U

J

Numbers
Percent

per tew

9.30

7.17

28.41
21.91

75.94
58.57

4.76
3.67

5.27
4.06

4.18
3.22

1.15
0.89

0.42
0.32

0.12
0.09

O.U

0.08

129.66
100.00

22

H

Numbers
Percent

per tow

0.12
0.11

25.08
23.12

79.39
73.19

1.83
1.69

0.97
0.89

0.63
0.58

0.16
0.15

0.13
0.12

0.09
0.08

0.07
0.07

108.47
100.00

2J

N

Numbers
Percent

per tow

33.55

68.47

2.82
5.76

10.87
22.18

0.23

0.47

0.36
0.74

0.41
0.84

0.3S
0.78

0.24
0.49

0.10
0.20

0.06
0.12

49.00
100.00

26

0

Numbers
Percent

per tow

23.16
100.00

0

0

0

0

0
0

0
0

0
0

0
0

0
0

0
0

0
0

23.16
lOO.OO

121

Total

Numbers
Percent

per tow

U.47
23.36

10.10
16.30

30.31
48.12

1.76
2.84

1.61
2.60

2.16
3.49

0.84
1.36

0.43
0.69

0.15
0.24

0.12
0.19

61.95
100.00

Suimer »»«r«i!« 1949-1950

37

0

Numbers
Percent

per tow

7.43
24.64

3.74
12.40

2.60
S.62

2.95
9.78

6.12
20.29

3.73
12.37

1.64

5.44

0.95
3.15

0.49
1.63

0.51
1.69

30.16
100.00

39

H

Numbers
Percent

per tow

0.15
0.36

12.54
30.U

U.90
35.81

3.00
7.21

3.40
8.17

4.26
10.24

1.78
4.28

0.82
1.97

0.37
0.89

0.39
0.94

U.61
lOO.OO

25

J

Nuabers
Percent

per tow

5.21
3.10

44.28
26.37

65.31
38.90

34.17
20.35

13.66
8.U

3.73
2.22

0.91
0.54

0.37
0.22

0.13
0.08

0.13

o.oe

167.90
lOO.OO

46

M

Numbers
Percent

per tow

0.26 190.05
0.10 72.05

50.22
19.04

14.09

5.34

5.62
2.13

2.35
0.89

0.64
0.24

0.34
0.13

0.15
0.06

0.07
0.03

263.79
100.00

46

N

Numbera
Percent

per tow

16.52
26.78

38.93

63.11

5.40
8.75

0.11
0.18

0.17
0.28

0.19
0.31

0.18
0.29

O.U
0.18

0.05
0.08

0.03
0.05

61.69
100.00

50

0

Numbera
Percent

per tow

12.04
32.37

23.91
64.27

1.25
3.36

0
0

0
0

0

c

0
0

0
0

0
0

0
0

37.20
100.00

243

Total

Numbers
Percent

per tow

7.34
7.51

55.40
56.65

20.92
20.75

7.13
7.29

3.98
4.07

2.12
2.17

0.78
0.80

0.40
0.41

0.19
0.19

0.17
0.17

97.80
100.00

Spring 1950 (subareas h

1. J. M.

and N)

19

H

Numbers
Percent

per tow

1.46
3.50

19.55
46.95

3.51
8.43

4.63
11.12

6.33
15.32

2.77
6.65

1.83
4.39

0.65
1.56

0.86
2.m

a.64

100.00

13

J

Numbers
Percent

per tow

28.88
42.53

25.74
37.91

3.80
5.60

5.26

7.75

3.15
4.64

0.64
0.94

0.26
0.38

0.06
0.09

0.12
0.05

67.90
100.00

21

H

Numbers
Percent

per tow

21.42
20.17

58.03
54.65

13.85
13.04

7.17
6.75

4.18
3.94

1.19
1.12

0.27
0.25

0.05
0.05

0.02
0.02

106.18
lOO.OO

25

N

Numbers
Percent

per tow

6.80
4.92

125.33
90.63

2.22

1.61

1.78
1.29

1.38
1.00

0.40
0.29

0.22
0.16

0.06
0.04

0.09
0.07

138;28
100.00

78

Total

Numbers
Percent

per tow

13.U
13.90

64.84
68.73

5.93
6.29

4.51
4.78

3.64
3.86

1.22
1.28

0.63
0.67

0.20
0.21

0.26
0.28

94.34
100.00

Table A-2. — Wmnbcr per tow and percentage age composition by depth zone, area

XXII

jober Numbers per tow;

of Depth age composition

ow zone (in percent)

Age group

27

1

fjumberg
Percent

per tow

3.30
22.42

0.78
5.30

1.74
U.82

5.49
37.30

1.84
12.50

0.92
6.25

0.26
1.90

0.20
1.36

0.08

0.54

0.09
0.61

U.72
100.00

65

2

Numbers
Percent

per tow

12.36
19.U

13.28
20.53

28.78
U.49

8.44
13.05

1.13
1.75

0.40
0.62

o.u

0.22

0.10
0.15

0.03
0.05

0.02
0.03

64.68
100.00

19

3

Numbers
Percent

per tow

4.25
69.90

0.16
2.63

0.22
3.62

0.61
10.03

0.37
6.09

0.19
3.13

o.u
i.ei

0.10
1.64

0.06
0.99

0.01
0.16

6.08
100.00

31

4

Numbers
Percent

per tow

0.37
2.12

0.34
1.94

1.09
6.23

9.22
52.75

1.61
9.21

2.16
12.36

0.94
5.38

0.83
4.75

0.50
2.86

0.42
2.40

17-48
100.00

Summer 1949

27

1

Numbers
Percent

per tow

0.05
0.04

106.58
90.62

3.38
2.87

2.15
1.83

3.58
3.04

1.24
1.06

0.34
0.29

O.U
0.12

0.05
0.04

0.10
0.09

U7.61
100.00

53

2

Numbers
Percent

per tow

0.60
0.25

176.54
74.75

21.45
9.08

25.45
10.78

8.87
3.75

2.27
0.96

0.58
0.25

0.28
0.12

0.11
0.05

0.03
0.01

236.18
100.00

15

3

Numbers
Percent

per tow

0
0

0.06
4.08

0.32
21.77

0.26
17.69

0.45
30.61

0.19
12.93

0.10
6.80

0.06
4.08

0.02
1.36

0.01
0.68

1.47
100.00

27

4

Numbers
Percent

per tow

0
0

0.22
1.06

1.14
5.52

4.08
19.75

7.34
35.53

3.60
17.43

1.75

8.47

0.99
4.79

0.72
3.48

0.82

3.97

20.66
100.00

Summer 1950

32

1

Numbers
Percent

per tow

0.07
0.13

9.10
17.47

32.99
63.33

2.80
5.38

2.03
3.90

3.49
6.70

1.15
2.21

0.35
0.67

0.07
0.13

0.04
0.08

52.09
100.00

51

2

Numbers
Percent

per tow

27.62
28.75

16.95
17.64

47.35
49.29

1.58
1.65

1.12
1.17

0.83
0.86

0.30
0.31

0.18
0.19

0.08
0.08

0.06
0.06

96.07
100.00

16

3

Numbers
Percent

per tow

2.49
47.61

0.53
10.13

0.52
9.94

0.15
2.88

0.19
3.63

0.49
9.37

0.36
6.88

0.26
4.97

0.13

2.49

O.U
2.10

5.23
100.00

19

4

Numbers
Percent

per tow

11.44
39.02

0.38
1.30

2.43
8.29

1.86
6.34

3.51
11.97

5.U

17.43

2.22

7.57

1.40
4.77

0.51

1.74

0.46
1.57

29.32
100.00

Summer averaKe 1949-1950

59

1

Numbers
Percent

per tow

0.06
0.07

53.71
65.U

19.U
23.69

2.50
3.05

2.74
3.34

2.46
3.00

0.78
0.95

0.25
0.30

0.06
0.07

0.07
0.09

82.07
lOO.OO

107

2

Numbers
Percent

per tow

U.23
8.60

96.00
58.02

34.51
20.86

13. U
8.10

4.96
3.00

1.54
0.93

0.44
0.27

0.23
O.U

0.10
0.06

0.05
0.03

165.47
100.00

31

3

Numbers
Percent

per tow

1.29
37.83

0.31
9.09

0.42
12.32

0.20
5.87

0.32
9.38

0.34
9.97

0.22

6.45

0.17
4.99

0.08
2.35

0.06
1.76

3.41
100.00

46

4

Numbers
Percent

per tow

4.73
19.51

0.29
1.20

1.57
6.89

3.16
13.04

5.77
23.80

4.22
17.41

1.94
3.00

1.16
4.79

0.63
2.60

0.67
2.76

24.24
100.00

Sorlnt 1950 teubsreas H

. J. M.

and N)

21

1

Numbers

Percent

per tow

2.35

0.92

174.47
80.86

16.83
7.90

9.25

4.29

7.79
3.61

2,84
1.32

1.33
0.62

0.44
0.02

0.46
0.02

215.76
100.00

33

2

Numbers
Percent

per tow

20.90
29.15

40.56
56.58

3.00
4.18

4.03
5.62

2.36
3.29

0.48
0.67

0.22

0.31

0.05
0.07

0.09
0.13

71.69
100.00

11

3

Numbers
Percent

per tow

U.31
55.51

1.76
6.83

0.74
2.87

1.87
7.25

3.39
13.15

1.62
6.28

1.21
4.69

0.38

1.47

0.50
1.94

25.78
lOO.OO

13

4

Numbers
Percent

per tow

9.73
70.25

2.78
20.07

0.15
1.08

0.27
1.95

0.45
3.25

0.19
1.37

0.08
0.58

0.04
0.28

0.18

1.30

13.85
100.00

Table A-3» — Wumbere per tow and percentage age composition by bottom type, (eand, atony, mud, mud and sand), area XXII

Bottom
typa

Numbers p«r tow; ,
age composition
(In percent)

Age

group

of
tows

0

1

2

3

4

5

6

7

8

9 •

Total

SunBner

1948

86

Sand

Numbers
Percent

per tow

10.99
22.53

9.78
20.04

19.12
39.20

6.47
13.26

1.32
2.71

0.60
1.23

0.22
0.45

0.17
0.35

0.07
O.U

0.04
0.08

48.78
lOO.OO

U

Steny

Numbers

Percent

per tow

0
0

3.39
9.10

20.26
54.40

11.52
30.92

1.45
3.39

0.36
0.96

0.15

0.44

0.08
0.22

0.02
0.05

0.01
0.03

37.24
100.00

23

Hud

Numbers
Percent

per tow

0.51
3.84

0.26
1.96

0.62
4.67

8.59
64.68

0.38
2.85

1.56
U.73

0.52
3.91

0.39
2.93

0.26
2.00

0.19
1.42

13.28
100.00

19

Mud-Sand

Numbers
Percent

per tow

1.47
11.75

0.16
1.2S

0.71
5.67

4.17
33.33

2.00
15.99

1.51
12.07

0.79
6.31

0.78
6.24

0.46
3.68

0.46
3.68

12.51
100.00

Sumner

1949

66

Sard

Numbers
Percent

per tow

O.U
0.24

152.85

84.35

9.92
5.47

10.39
5.73

4.95
2.73

1.84
1.02

0.45
0.25

0.22
0.12

0.09
0.05

0.06
. 0.03

181.21
100.00

23

Stony

Numbers
Percent

per tow

0.17
O.U

U.96
35.25

23.04
19.36

34.57
29.03

14.10
11.84

2.68
2.25

1.12
0.94

0.58
0.48

0.40
0.34

0.41
0.37

U9.03
100,00

19

Mud

Numbers
Percent

per tow

0
0

0.18
1.12

0.35
5.29

1.93
12.33

6.01
37.42

3.35
20.86

1.57
9.78

0.88
5.48

0.57
3.55

0.67
4.17

16,06
100. 00

U.

Hud-Sand

Numbers
Percent

per tow

0
0

84.64
93.31

4.45
4.91

0.18

0.20

0.51
0.56

0.50
0.55

0.22
0.24

0.11
0.12

0.07
0.08

0.03
0.03

90.71
100.00

Summer

1950

67

Sand

Numbers
Percent

per tow

21.35
36.08

10.68
15.0?

31.86
44.89

1.75
2.47

1.47
2.07

2.31
3.25

0.69
1.25

0.42
0.59

0.15
0.21

0.10
O.U

70.98
100.00

18

Stony

Numbers
Percent

per tow

2.90
2.63

22.53
20.47

74.21
67.26

4.04
3.66

3.54
3.20

2.33
2.U

0.46
0.42

0.16
0.15

0.04
0.04

0.07
0.06

U0.33
100.00

15

Hud

Numbers
Percent

per tow

15.48
47.97

3.54
10.97

5.00
15.49

1.00
3.10

1.35
4.18

2.77
8.58

1.43
4.43

0.98
3.04

0.37
1.15

0.35
1.09

32.27
100.00

21

Hud-Sand

Numbers
Percent

per tow

1.72
13.35

2.25

17.47

5.80
45.03

0.36
2.80

0.62
4.81

l.U
8.62

0.56
4.35

0.27
2.10

O.U
0.85

0.08
0.62

12.88
100.00

Sujnner averaKe 19^*9-1950

133

Sand

Numbers
Percent

per tow

10.79
8.65

81.23
64.63

20.98
16.69

6.04
4.81

3.19
2.54

2.07
1.65

0.68
0.54

0.32
0.25

0.12
0.10

0.08
0.06

125.68
100.00

U

Stony

Numbers
Percent

per tow

1.37
1.19

33.45
29.02

45.51
39.50

21.17
18.38

9.47
8.22

2.52
2.19

0.83
0.72

0.39
0.34

0.24
0.21

0.26
0.23

U5.21
100.00

V.

Hud

Numbers
Percent

per tow

6.83
29.43

1.66
7.15

2.68
11.55

1.55
6.63

3.95
17.02

3.09
13.30

1.51
6.41

0.93
4.01

0.43
2.07

0.53
2.28

23.a
100. OO

35

Hud-Sand

Numbers
Percent

per tow

1.03
2.34

35.20
79.98

5.26
11.95

0.29
0.66

0.58
1.32

0.37
1.98

0.42
0.95

0.21
0.48

0.09
0.20

0.06
O.U

U.Ol
100.00

Sprlnj! 1950 (subareas H. J,

, M. and

N)

W

Saisl

Numbers
Percent

per tow

9.80
7.97

96.26
78.31

4.44
3.61

5.09

4.14

4.37
3.56

1.50
1.22

0.86
0.70

0i27
0.22

0.33
0.27

122.93
100.00

20

Stony

Numbers
Percent

per tow

20.71
31.U

21.86
33.16

l;!.45
18.89

5.33
8.09

3.69
5.61

1.16
1.76

0.40
0.61

O.U
0.17

0.20
0.30

65.92
100,00

2

Hud

Numbers
Percent

per tow

0
0

0
0

0
0

0.09
5.32

0.51
34.00

0.31
20.69

0.13
8.67

0.16
10.67

0.31
20.67

1.50
100.00

3

Mud-Sand

HuMbers
Percent

per tow

0
0

17.31
100.00

0
0

0
0

0
0

0
0

0
0

0
0

0
0

17.31
100.00

(Bottom types grouped-sand-sand and stony,
Sujmor 1948

mud-raic

1 and mud-sand^

area XHI

100

Sand

Numbers
Percent

per tow

9.45
20.04

8.89
13.85

19.27
40.86

7.17
15.20

1.34
2.84

0.57
1.21

0.S1
0.45

0.16
0.34

0.D6
0.13

0.06
OJX

47.16
100.00

U2

Hud

Numbers
Percent

per tow

0,95
7.34

0.21
1.62

0.67
5.18

6.59
50.93

1.11
8.58

1.54
U.90

0.64
4.95

0.57
4.40

0.35
2.70

0.31
2.40

12.94
100.00

Summer

1949

89

Sand

Numbers
Percent

per tow

0.37
0.22

154.19
75.20

13.32
8.07

16.64
10.03

7.31
4.42

2.06
1.25

0.63
0.38

0.32
0.19

0.17
0.10

0.15
0.09

165. U
100,00

33

Nod

Numbers
Percent

per tow

0
0

36.01
75.44

2.38
4.99

1.22
2.56

3.67
7.69

2.U
4.47

1.00
2.09

0.56
1.17

0.36
0.75

0.40
0.84

47.73
100.00

Sunser

1950

8!

Sand

Numbers
Percent

per tow

17.45
22.00

13.20
16.64

40.82
51.46

2.24
2.82

1.91
2.U

2.31
2.90

0.80
1.01

0.37
0.47

0.13
0.16

0.10
0.13

79.32
lOO.M

36

Mud

Kuoben
Percent

p«r tow

7.45
35.54

2.79
13.31

5.47
26.10

0.63
3.00

0.93

4.44

1.80
8.59

0.92
4.39

0.57
2.72

0.21
1.00

0.19
0.91

20.96
100,00

Sujmer.

tnrue 1949-1950

m

3and

NuBbera
Percent

per tow

8.71
7.07

69.97
56.79

26.76

21.72

9.60
7.79

4.67
3.79

2.18

1.77

0.71
0.58

0.34
0.27

0.15
0.12

0.12
0,10

123,21

100,00

69

Mud

Numbers
Percent

per tow

3.89
U.52

18.68
55.33

3.99
11.82

0.91
2.70

2.24
6.63

1.96
5,81

0.96
2.84

0.56
1.66

0.23
0,83

0,29
0,86

33,76
100,00

SpriJU 1950 (1

Bubareaa

H. J. H.

and N)

68

Sand

Numbers
Percent

per tow

y:?J

74.38
70.06

6.80
6.40

4'.86

4.17
3.93

1.40
1.32

o'.ie

0.23
0.25

0,29

W.^

10

Mud

Numbers
Percent

per tow

13.85
97.98

0

0

0
0

0.02
0,U

0.10
0,68

0.06
0,41

0.03
0.20

0.03
9.29

O.oi
0,40

U.ll!
lOO.OO

Table A-/,. — ffumbers per tow of each age by bottom type and depth zone« Subarea G.

Depth
zone

Bottom
type

Number
of tows

Age group

Summer 19m

Sand
Stony
Hud

Mud and sand
Total

.29 10.27 1.5.9

20.93 11.71

3.1*8 2.56

1.03

0
2.67

00000000
6.19 6.85 30.65 13.95 7.61 2.32 1.71 0.69

0

o.ei

0
73.65

Sand
Stony
Mud

Mud and sand
Total

6.50

1..00 12.70

0.15

6.50 1..00 12.70 1,.25 0.80 0.15

Sand
Stony
Mud

Mud and sand
Total

19.30 0.93 1.19 3.60 1.82 1.06 0.64 0.65 0.36

19.30 0.93 1.19 3.60 1.82 1.06 0.64 0.65 0.36

0.04

Sand
Stony
Hud

Hud and sand
Total

0.50 0.45
0.50 0.45

1.12 14.96
1.12 14.96

0.50 2.70
0.50 2.70

0.8
0.8

0.65
0.65

0.40
0.40

0.25
0.25

22.a
22.41

Sand

Stony

Mud

Mud and sand

4.15

0.50 0.45
0 0

8.32 13.31

1.12 L4.96
0 0

5.61

0.50
0

2.70

0

0.88
0

0.65
0

0.35
0.40

0.25
0

22.41
0

Sand

Stony

Mud

Mud and sand

Total

3.39 U.65 20.62

7.63

3.39 U.65 20.62 7.63

Sand

Stony

Hud

Hud and sand

Total

8.34 0.69 0.33

0.56

0.69 0.33 0.56

Sand

Stony

Mud

Hud and sand

Total

0.01 0.80
0.01 0.80

1.04 2.79
1.04 2.79

0.8

O.Si

0.65 0.63 0.17
0.65 0.63 0.17

0.03
0.03

7.00

7.00

Sand
Stony
Hud

Hud and sand
Total

0.31
0.26

0.93
1.40
1.33

2.36 4.08
3.33 10.12
3.18 9.19

1.50
5.70
5.06

0.62 0.45 0.?5
2.65 1.47 0.96
2.34 1.31 0.85

0.08
1.16
0.99

10.27
27.10

24.51

Sand 8

Stony 0

Mud 12

Mud and sand 0

0.13
0

5.04
0.29

2.10

1.35

6.50 11.74
3.14 9.51

4.21
5.30

1.21
2.48

0.55
1.40

0.21
0.89

0.12
1.07

31.54
25.43

Summer 1950

Sand
Stony
Hud

Mud and sand
Total

23.74 U.60

23.74 11.60

3.32

1.55 1.73

Sand
Stony
Hud

Hud and sand
Total

25.00 14.10

1.00
13.00

1.91
8.00

1.46

0.09

0.78

0

0.37

0.60 0.09

0 0
0.30 0.05

3.00
22.50

Sand

Stony

Mud

Mud and sand

Total

8.30
8.00

3.23

0.88 0.30 0.23

0 1.17 0.64

0.66 0.52 0.33

0.49 0.83 0.43
0.18 0.01 0
0.41 0.63 0.32

0.24 0.15

0 0

0.18 0.11

0.05

11.90
10.00

11.43

Sand
Story

Mud

Mud and sand 0
Total 8

26.90
26.90

0.60
0.60

3.08
3.08

0.99
0.99

1.71 4.U
1.71 4.U

2.18

2.18

1.63
1.63

0.65
0.65

0.62
0.62

42.50
42.50

Sand

Stony

Mud

Hud and sand

7.13 12.56

1.63 0.96 1.11

0.07 0.02

24.80
1.00

0.53

1.91

2.87
0.09

0.95
0

1.54
0

3.68
0

1.94
0

1.45
0

0.58
0

0.55

0

38.89
3.00

Table A-S.—Mumbers per tow of each age by bottom type and depth zona. ^ Sub- rea H

Depth
zone

Bottom
type

Number of tows
for each age group

Ace group

,_SprlJV^ 1943

Sand

Stony

Mud

Mud and sand

Total

0.04 0,37 0.08 0.01

0 0.04 0.57 CO-^ 0.01

Sand

Stony
Mud

Mud and sand
Total

1.60 8.77 39.53 U.b5 1.16 0.18 0.01

1.60 8.77 39.53 11.65 1.16 0.16 0.01

0 62.90

Sand

Stony

Mud

Mud and sand
Total

0

0

0

0.37

l.U

0.40

0.06

0.03

0

0

2.00

0

0

0

0.37

l.U

0.1.0

0.06

0.03

0

0

2.00

0

0.29

0.50

0.61

0.i,6

0.36

0.22

0.24

o.u

0.01

2.70

0
0.60
0.30

0
0.54
0.39

0.02
2.46

2.77

12.90

6.97

1.05

5.72
3.15

0.36
4.92
2.60

0.49
2.86
1.57

0.53
2.90

1.60

0.76
1.76

1.00

1.02
1.73
0.97

7.00
36.39
19.98

Sand
Stony
Hud

Mud and sand
Total

4
0
1
5
10

Sand

Stony

Kud

Mud and sand

13
0

0.36

0
0.60

4.81 21.45

6.60 0.73

0.07 0.07

0 0.01 1.57
0.54 2.46 12.90

1.10
5.72

0.33
4.92

0.28
2.86

0.28
2.9C'

0.38
1.76

0.51
1.73

4.51
36.39

'^vm't ''%''

Sand
Stony
Mud

Hud and sand
Total

81.22
0

64.98

3.47
0

2.84
0

3.54
0

0.76
0

0.28
0

0.22
0

0.05
0

0.52
0

2.73 2.27

2.33 0.61 0.22 0.13 0.04

92.90
0

Sand
Stony
Mud

Mud and sand
Total

0.50 23.48

3.52 0.72 0.26

0.50 23.48 3.52

0.72

0.26 0.02

28.50

28.50

Sand
Stony
Mud

Mud and s^Jid
Tot.^1

0.17 1.03 0.26

0 0 0

0.11 0.69 0.17

0.04

0

0.03

1.50

0

1.00

Sand

Stony

Mud

Hud and sand

Total

0.34

0
1.11

0 0.13
0.15 0.52

0.05 0.44 0.10
5.04 9.06 4.07

1.23 3.57 3.53
2.53 4.97 2.63

0.01

3.05

1.54
1.70

0

1.06

0.73
0.91

0
1.63

0.50
0.33

0
1.84

0. !2
0.87

0.60
27.80

11.50
15.11

Sand

Stony

Mud

Mud and sand

11
5
1
2

0.09 33.30 1.90

0 0.27 0.89

0 0 0

0 0 0.13

1.21 1.64 0.36

4.03 7.25 3.09

0 0 0

1.23 3.57 3.53

0.11

2.44

0

1.54

0.08

1.33

0

0.78

0.02

1.30

0

0.50

0.19

1.47

0

0.22

39.40

22.07

0

11.50

Summer 1950

Sand
Stony
Mud

Mud and sand
Total

6.37

0

48.24

0

10.01

88.19
0

48.24
0

61.15

12.42 9.61 19.00

0 0 0

6.44 6.48 8.44

0 0 0

8.57 6.82 12.92

6.U
0

3.99
0

4.32

1.77
0

1.61
0

1.31

0.31
0

0.29
0

0.23

0.21
0

0.27
0

0.16

U.3.99
0

124.00
0

105.49

Sand
Stony
Mud

Mud and Band
Total

9.97 1';.78 2.53 2.38

3.60 1.03 0.54

0
4.99

0
9.89

0
1.26

0

1.19

0
l.SO

0
0.52

0

0.27

0.20

0

0.10

o.u

0

0.07

40.17

0
20.09

Sand
Stony
Mud

Mud and sand
Total

4.00 0 0.95

0 2.95 1.92

1.33 1.97 1.60

0.05
0.19
0.14

0 0 0

0.35 2,13 1.84
0.24 1.42 1.23

0

1.31
0.37

0
0.66
0.44

0
0.65
0.43

5.00
12.00

9.67

Sand
Stony
Mud

Mud and sand
Total

0.67 1.48

0.67

1.48

3.10

6.81

3.83

3.83

2.92

1.01

0.78

20.60

20.60

Sand
Stony
Total Hud

Mud and sand

11
1
2
6

0 5.61 45.66

0 0 0

2.00 24.12 24.59

0 0.98 0.64

6.74

0

3.24

0.06

5.86 U.43 4.10

0 0 0

3.24 4.22 2.00

0.12 0.71 0.61

1.75

0

0.30

0.44

0.47

0

0.15

0.22

0.35

0

O.U

0.22

82.02

0

64.50

4.00

Spring 1950

Sand

Stony

Mud

Mud and sand
Total

0.30 34.57
17.00 13.75

13.27
7.68

13.99
9.34

17.65
8.60

7.35
3.31

4.71
2.02

1.78
0.46

1.93
1.34

3.64 7C.41 12.15 13.16 15.84

U5.55
64.00

Table A-5. — Wumb-?r9 per tow of each age by bottom type and depth zone. Subarea H - Continued.

Depth
sone

Bottom
type

Number of tows
for each age group

Age group

Spring 1950 t cont . )

Sand
Stony
Hud

Mud and sand
Total

0.90

0.25 0.54

0.19 0.06 0.05

0.25 0.54 0.78 0.19 0.06 0.05

Sand
Stony
Mud

Mud and sand
Total

7.42

0

4.95

2.27
0

9.75
0

18.63
0

8.93
0

6.66
0

2.11
0

1.51 6.50 12.42 5.95 4.44 l.U

2.74

0

1.83

58.51

0

39.01

Sand
Stony
Hud

Mud and sand
Total

2.00
1.00
0
0.30
0.86

0.43

0.50

0

0

0.23

0.29
0
0
0

0.07

0.47
0.01
0.17
0
0.14

0.52
0.22
1.02
0
0.31

0.23
0.21
0.62
0
0.19

0.05

0.05

0.26

0

0.06

0
0

0.31
0

0.04

0.01
0.51
0.62
0
0.21

4.00
2.50
3.00
0.30
2.U

Sand

Stony

Mud

Mud and sand

U
3
2
3

0.72 32.42 5.36

6.33 4.92 2.56

0 0 0

0.30 0 0

7.09

3.28

0.09

0

10. U
3.01
0.51

0

4.39 2.95 1.04

1.24 0.71 0.15

0.31 0.13 0.16

0 0 0

1.21

0.79

0.31

0

65.30
23.00
1.50
0.30

S»

Tabla A-6. — HaTuerB per tow of each ape by bottom type and deptii zone. Subarea J

Depth
aone

Oottom
typo

Number
of tOWB

Sand
Stony
Mud

Hud and sand
Total

0 0.41 8.79 13.15 2.55 0.51 0.17 0.10 0.03 0.03 30.74

B.79 IS. 15 2.55

0.51 0.17 0.10 0.03

0.03

30.74

Sand 7

Stony 5

Mud 0

Mud and sand 0
Total 12

0 70.35 146.19 44.26
0 7.42 49.48 21.36

44.13 105.89 34.72 4.28

5.53

1.65

0.33

0.23

0.06

0.04

268.64

2.52

0.70

0.31

0.17

0.03

0

-J1.99

0.02 190. e?

Sand

Stony

Hud

^fud and sand

Total

Sand
Stony
Mud

Mud and sand
Total

0

0.11

0.74

1.39

0.51

0.32

0.27

0.18

0.05

0.02

3.59

2.00

0.33

C.39
0.16

1.32
0.82

U.71
3.59

9.39
1.99

4.14
0.96

C.76
0.35

0.30
0.20

0
0.04

0
0.02

33.00
8.46

0.16
0

37.92

4.79

79.00
34.22

24.37
20.16

3.18
2.53

1.01
0.63

0.28
0.26

0.19
0.L4

0.05
0.03

0.03

0.01

146.19

62.77

Sand 13

Stony 8

Hud 0

Mud and sand 1

1.32 1A.71

6.39

0.76

Suir.mer 1949

Sand
Stony
Hud

Mud and sand
Total

0 78.34 70.60 48.20 2.87
0 104.94 81.73 115.56 38.43

0
4.49

0
0.87

0
0.31

0
0.13

0 200.00
0.04 346.50

0 101.14 80.14 105.94 33.35 3.85 0.74 0.27 O.U 0.03 3^5.57

I<o tows

IJo tows

No tows

Sand
Stony
Mud

Mud and sand
Total

0 0.32 2.19 U.51 8.54 1.94 0.37 0.37 0.20 0.36 25.80

0 0.32 2.19 11.51 8.54 1.94 0.37 0.37 0.20 0.36 25.80

Sand 1

Stony 10

Mud 0

Mud and sand 0

0 78.33 70.60 48.20 2.87 0 0 0 0 0 200.00

0 63.09 49.92 73.94 26.47 3.47 0.67 0.33 0.16 0.17 218.22

Summer 1950

Sand

Stony

Mud

Mud and sand
Total

6.60 132.96 6.23 2.44 0.68 0.09

6.60 132.96 6.23 2.44

Sand
Stony
Hud

Hud and sand
Total

100.00
5.20

2.64 25.30
77.23 176.97

3.24
6.S6

3.62
4.79

0.55
2.57

0.15
0.35

0

0.03

a.OC 64.80 151.77 6.26 4.59 2.23 0.32 0.03

0 136.00
0 274.00

251.00

Sand
Stony
Hud

Mud and sand
Total

0.01 0.85 0.77 0.89 0.26

J.OQ

Sand

Stony

Mud

Sand
Stony
Mud

Hud and aand
Total

0.30 0.58 3.58 4.50

6.41 1.34 0.43

0.13

0.24

6.04 1.59 1.44 1.24 0.55 0.13 0.01

6.04 1.59 1.44 1.24

0.13 0.01

25.72

Mud and
Total

sand

2
6

0
0.20

0
0.39

2.60
3.25

2.44
3.81

5.48
7.30

9.02
7.28

3.99
2.23

1.54
0.80

0.43
0.23

0.21
0.23

25.71
25.72

Total

Sand
Stony
Mud
Hud and

sand

1
11
0
2

100.00
2.75

0

2.64
35.92

0

25.80

93.83
2.60

3.24
5.32

2.44

3.62
5.38

5.48

0.55
3.64

9.02

0.15
0.72

3.99

0
0.25

1.54

0
0.07

0.43

0

0.11

0.21

136.00
U7.99

25.71

Sprlns

1950

11.00

Sand

Stony
Mud

Kud and sand
Total

0
0

2.00
42.30

42.73
U.93

6.78
6.61

5.81

9.79

2.4i,
5.67

0.24
1.09

0
0.45

0

0.10

0
0.13

60.00
108.07

0

36.54

42.05

6.63

9.22

5.21

0.97

0.39

0.09

O.U

101.21

' towa

Sand

Stony

Hud

Mud <jid sand
Total

8.57 0.33 0.59 0.82 0.24 0.13

0 0

0 23.92

0
6.86

0
0.27

0
0.47

0
0.66

0
0.19

0

0.10

0
0.03

0
0.14

0
32.64

Sand 1

0

2.00

42.76

6.78

5.81

2.44

0.24

0

0

0

60.03

Stony 11

0

33.95

26.54

3.87

5.69

3.50

0.73

0.30

0.07

0.13

74.78

Total

Mud 0

Mud and sand 1

0

0

0

0

0

0

0

0

0

0

0

Table A-T.—Numbara par tow of each ape by bottom type and depth zone. Subaraa H

Dapth

Bottom

typa

Nunbsr
of tows

Age group

lona

0

1

2

3

4

5

6

7

8

9/

Total

Sunmer

1948

Sand

h

0.30

0.30

0

0

0

0

0

0

0

0

0.60

Stony

1

0

0

0

0

0

0

0

0

0

0

0

I

Kud
Mud and

sand

1
0

0

0

0

0

0

0

0

0

0

0

0

Total

6

0.20

0.20

0

0

0

0

0

0

0

0

0.40

Sand

10

0

2.06

4.07

1.63

0.41

0.23

0.33

0.33

0.13

0.07

9.26

Stony

2

0

t.1.0

4.60

0

0

0

0

0

0

0

9.00

11

Mud
Mud and

sand

0
0

Total

1!

0

2.1.5

4.16

1.36

0.34

0.19

0.23

0.28

0.11

0.06

9.23

Sand

1

20.00

0

0

0.50

0.40

0.10

0

0

0

0

21.00

Stony

3

0

0.10

0.20

0

0

0

0

0

0

0

0.30

ni

Mud
Mud and

sand

0
0

Total

1.

5.00

0.08

0.15

0.13

0.10

0.03

0

0

0

0

5.49

Sand

2

0

0

0

0

0

0

0

0

0

0

0

Stony

0

IT

Hud
Hud and

!tand

0
0

Total

2

0

0

0

0

0

0

0

0

0

0

0

Sand

17

1.25

1.28

2.39

0.99

0.27

0.14

0.19

0.19

0.08

0.04

6.32

Stony

s

0

1.82

1.96

0

0

0

0

0

0

0

3.78

Total

Hud
Mud and

sand

1
0

0

0

0

0

0

0

0

0

0

0

0

Summer

1949

Sand

T

0

0

0

0

0

0

0

0

0

0

0

Stony

L

0

43.80

0

0

0

0

0

0

0

0

43.80

1

Hud
Hud and

sand

0

0

Total

7

0

25.03

0

0

0

0

0

0

0

0

25.03

Sand

13

0.1.0

601.1.6

U.32

44.01

16.45

6.44

1.47

0.73

0.30

0.09

715.67

Stony

1

1..00

156.60

22.35

33.01

21.39

9.25

6.19

2.98

0.94

0.29

257.00

II

Mud
Mud and

sand

0
0

Total

H

0.66

572.1.7

39.96

43.23

16.30

6.64

1.31

0.89

0.35

0.11

682.91

Sand

0

Stony

3

0

o.n

1.33

0.85

0.65

0.45

0.24

0.10

0.05

0.02

4.00

III

Hud
Hud and

sand

0

0

Total

3

0

0.31

1.33

0.85

0.65

0.45

0.24

0.10

0.05

0.02

4.00

IV

No towa

No towa

No tows

Sand

16

0.33

1.91.12

33.57

35.76

13.37

5.23

1.20

0.59

0.24

0.07

581.48

Stony

3

0.50

U.59

3.29

4.45

2.92

1.33

0.86

o.u

O.U

0.04

55.53

Total

Hud

Mud and

sand

0
0

Sujnroer

1950

Sand

2

0

1.0.11

133.27

0.90

0.50

0.19

0.03

0

0

0

175.00

Stony

2

0

0

0

0

0

0

0

0

0

0

0

I

Mud

0

Mud and

sand

1

0

39.41

112.70

2.33

1.31

0.97

0.10

0

0

0

156.87

Total

^

0

23.93

75.85

0.83

0.46

0.27

0.03

0

0

0

101.37

Sand

13

0.20

32.36

31.72

1.64

1.06

0.80

0.23

0.22

0.15

0.12

113.50

Stony

2

0

5.73

151.86

7.08

2.25

0.94

0.12

0.02

0

0

163.00

n

Mud
Mud and

sand

0
0

Total

15

0.17

23.81

91.07

2.36

1.22

0.32

0.22

0.19

0.13

O.U

125.10

Sand

1

0

0

1.36

0.63

0.72

0.25

0.04

0

0

0

3.00

Stony

1

0

0

0

0

0

0

0

0

0

0

0

III

Mud
Mud and

.sand

0
0

Total

2

0

0

0.68

0.32

0.36

0.12

0.02

0

0

0

1.50

17

No tows

No tows

No towa

Sand

16

0.16

31.31

83.14

1.48

0.97

0.69

0.19

0.18

0.12

0.10

ua.34

Stony

5

0

2.29

60.74

2.83

0.90

0.33

0.05

0.01

0

0

67.20

Total

Mud

0

Hud and

sand

1

0

39.U

112.70

2.33

1.31

0.97

0.10

0

0

0

156.37

Spring

1950

Sand

U

0

137.71

14.11

17.17

10.23

2.74

0.72

0.05

0.04

182.77

atony

3

0

0.30

63.44

9.06

3.43

3.81

0.83

0.31

0.06

36.24

I

Mud
Mud and

sand

0
0

Total

7

0

78.82

35.25

13.69

9.46

3.20

0.77

0.16

0.05

1U.40

Sand

10

42.80

53.72

3.53

4.75

2.05

0.26

0.04

0

0

107.20

Stony

1

2.00

125.23

4.80

6.03

0.94

0

0

0

0

139.00

II

Mud
Mud and

sand

0
0

Total

11

39.09

60.22

3.69

4.37

1.95

0.24

0.04

0

0

110.09

Tabla A-7. — Mumbera per tow of aach age by bottom type and depth zontj. Subar«a M - Contlnuad

D«pth
■one

Bottom
type

Number

of tOW8 0

Sand 1

Stony 2

Hud 0

Hud and sand 0

Total 3

Ag« group

9/

Spring 1950 - Contlnuad

0 0 0 0 0
9.91 2.26 1.78 0.51 0.01

6.61 1.51 1.19 0.36 0.01

0
U.50

9.67

n

Sard 15

Stony 6

Total Mud 0

Mud and sand 0

28.53

72.53

6.15

7.75

i.09

0.90

0.22

0.01

0.01

120.21

3.61.

21.79

33.11

5.71

1..37

1.91

O.U

0.15

0.03

71.12

Tabls A-8. — Numbera par tow of each aga by bottom type and depth gone. Subaraa 1

Depth
Bone

Bottom
type

Number
of tovra

Age group

9/

S&nd
Stony
Hud

Mud and sand
Total

Sand
Stony
Mud

Mud and sand
Total

33.80 16.19 15.17 1.02 0.16 0.37 0.12 0.06 0.01

38.80 16.19 15.17 1.02 0.16 0.37 0.12 0.06 0.01

Sand
Stony
Hud

Hud and sand
Total

0.30

0 0

0.13 0

0
0.13

Sand

22

Stony
Mud

0
0

Mud and sand

28.32 10.25 9.65 0.65 0.10 0.21. 0.08 O.Ot 0.01

Summer 19A9

Sand
Stony
Hud

Mud and sand
Total

0.20 207.33 0.92

0.20 207.38 0.92

Sand
Stony
Hud

Mud and sand
Total

12
0
0
0

12

1.70 1.0.36 0.32

Sand 2

Stony 0

Mud 0

Mud and sand 3

Total •■

Sand
Stony
Mud

Mud and sand
Total

Sand 20

Stony 0

Hud 0

Hud and sand u

1.08 86. U 0.1.7

Summer 1950

Sand
Stony
Mud

Mud and sand
Total

0 2.75 3.90 0.16 0.21 0.18 0.05 0.06 0.06 0.03

0 2.75 3.90 0.16 0.21 0.13 0.05 0.06 0.06 0.03

Sand
Stony
Hud

Hud and sand
Total

11
1
0
0

12

65.10 1,.38 19.96 0.38 0.62 0.73 0.73 O.U 0.18 0.11
22.00 000000000

61.51 i.Ol 18.30 0.35 0.57 0.67 0.67 0.1.0 0.16 0.10

92.63
22.00

Sand
Stony
Hud

Hud and sand
Total

Sand

Stony

Hud

Hud and sand

W..76 3.87 U.91. 0.31 0.1,9 0.56 0.52 0.32 O.U 0.09
22.00 000000000

66.00
22.00

Spring 1950

Sand
Stony
Mud

Mud and sand
Total

3.90 3U.26 5.55 3.89 2.11 0.1.9 0.20 0.06 0.01.

3.90 3U.26 5.55 3.39 2.U 0.1.9 0.20 0.06 0.01.

360.50

Sand
Stony
Mud

Mud and sand
Total

0.10 31.59 0.92 l.U 1.48 0.50 0.32 0.03 0.13

0.10 31.59 0.92 1.11 1.1.8 0.50 0.32 0.08 0.18

36.23

Table A-9. — Hunbers per tow of each a^e by bottom type and depth zone. Subarea M - Continued

Depth
zone

Age group

Bottom
type

Number
of tows

9/

Spring 1950 - Continued

Sand
Stony
Hud

Mud and aand
Total

3t.J.O
27.52

31.1.0
27.52

No tows

No tows

No tows

Sand 21

Stony 0

Total Hud 0

Kud and sand U

1.54 U9.20 2.6i 2.11 1.65 0.17 0.26 0.07 0.12 15S.06

3H0 00000000 31.. iO

Table A-9.

—Numbers per tow of

each ace.

by bottom type and depth zone.

Subarea 0

Bottom
type

Number
of towa

Age group

Depth
zone

0

1

2

3

k

5

6

7

s

9/

Total

Sunner 1918

Sand

L

0

0

0

0

0

0

0

0

0

0

0

Stony

0

I

Mud

2

0

0

0

0

0

0

0

0

0

0

0

Mud and

sand

2

0.50

0

0

0

0

0

0

0

0

0

0.50

Total

3

0.13

0

0

0

0

0

0

0

0

0

0.13

Sand

8

2/.. 50

0.15

1.25

0.35

0.57 0

.22

0.0/.

0.02

0

0

27.10

Stony

0

II

Hud

1.

1.30

0

0

0

0

0

0

0

0

0

1.30

Hud and

sand

U

5.50

0

0

0

0

0

0

0

0

0

5.50

Total

16

13.95

0.07

0.62

0.18

0.29 0.11

0.02

0.01

0

0

15.25

Sand

0

Stony

0

III

Mud

1

0

0

0

0

0

0

0

0

0

0

0

Mud and

sand

2

0

0

0

0

0

0

0

0

0

0

0

Total

3

0

0

0

0

0

0

0

0

0

0

0

IT

No tows

No tows

No

tows

Sand

Stony

Hud

12

16.32

0.10

0.83

0.23

0.38 0

.15

0.03

0.01

0

0

13.07

Total

7

0.71.

0

0

0

0

0

0

0

0

0

0.71.

Mud and

sand

8

2.88

0

0

0

0

0

0

0

0

0

2.33

Sunnuer 19C9

Sand

U

0

0

0

0

0

0

0

0

0

0

0

Stony

0

I

Hud

0

Mud and

sand

1

0 U09.78

58.22

0

0

0

0

0

0

0

1168.00

Total

^

0

221.96

11.64

0

0

0

0

0

0

0

233.60

Sand

6

0

1.76

o.oh

0

0

0

0

0

0

0

1.80

Stony

0

II

Hud

5

0

0

0

0

0

0

0

0

0

0

0

Hud and

sand

5

0

15.03

0.77

0

0

0

0

0

0

0

15.80

Total

16

0

5.35

0.26

0

0

0

0

0

0

0

5.61

Sand

0

Stony

0

III

Mud

1

0

0

0

0

0

0

0

0

0

0

0

Hud and

sand

2

0

0

0

0

0

0

0

0

0

0

0

Total

3

0

0

0

0

0

0

0

0

0

0

0

IV

No tows

No tows

No

tows

Sand

10

0

1.06

0.02

0

0

0

0

0

0

0

1.03

Stony

0

Total

Mud

6

0

0

0

0

0

0

0

0

0

0

0

Mud and

sand

8

0

U3.12

7.76

0

0

0

0

0

0

0

155.38

Simmer 1950

Sand

6

0

0

0

0

0

0

0

0

0

0

0

Stony

0

I

Hud

1

0

0

0

0

0

0

0

0

0

0

0

Hud and

sand

3

0.70

0

0

0

0

0

0

0

0

0

0.70

Total

10

0.21

0

0

0

0

0

0

0

0

0

0.21

Sand

10

56.20

0

0

0

0

0

0

0

0

0

56.20

Stony

0

II

Mud

2

2.50

0

0

0

0

0

0

0

0

0

2.50

Mud and

sand

1

32.00

0

0

0

0

0

0

0

0

0

32.00

Total

13

i.6.03

0

0

0

0

0

0

0

0

0

1.6.08

Sand

0

Stony

0

III

Hud
Hud and

sand

1
0

0

0

0

0

0

0

0

0

0

0

0

Total

1

0

0

0

0

0

0

0

0

0

0

0

Sand

0

Stony

0

IV

Mud

0

Mud and

sand

2

0.50

0

0

0

0

0

0

0

0

0

0.50

Total

2

0.50

0

0

0

0

0

0

0

0

0

0.50

Sand

16

35.13

0

0

0

0

0

0

0

0

0

35.13

Stony

0

Total

Mud

1.

1.25

0

0

0

0

0

0

0

0

0

1.25

Hud and

sand

6

5.85

0

0

0

0

0

0

0

0

0

5.35

lDl*rlor — [>wpll«atlB| Siotlss,

LaroB. D C. DTIT