SH 151
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Copy 1 . a

aO4

[ARTICLE 19._EXTRACTED FROM THE BULLETIN OF THE U. S. FISH COMMISSION
FOR 1894. Pages 289 to 314.] R

FEEDING AND REARING FISHES, PARTICULARLY
_ TROUT, UNDER DOMESTICATION.

BY

WILLIAM F. PAGE.

WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1895.

SH 151
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Copy 1

[ARTICLE 19.—EX'TRACTED FROM THE BULLETIN OF THE U. S. FISH COMMISSION
FOR 1894. Pages 289 to 314.)

FEEDING AND REARING FISHES, PARTICULARLY
TROUT, UNDER DOMESTICATION.

BY

WILLIAM F. PAGE.

WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1895,

7 (eae A

985

19.—FEEDING AND REARING FISHES, PARTICULARLY TROUT, UNDER
DOMESTICATION.

3y WILLIAM F. PAGE,
Superintendent of United States Fish Commission Station at Neosho, Missouri.

ARTIFICIAL FOOD.

In the summer of 1893 I presented a paper at the Chicago meeting of the American
Fisheries Society under the title: Plant Yearlings Where Needed. <A portion of the
paper contained a summary of some studies which I had made on feeding and rearing
fishes. The present paper is an elaboration of that summary by adding the results
of further study and investigation.

To the fish-culturist striving to improve methods and results the importance of
the question of fish food can scarcely be exaggerated. Aside from the interest on the
cost of the plant and pay of the necessary employés, it is the principal fixed charge,
and in most cases the only item of expense capable of reduction, or, what amounts to
the same thing, the most promising field for obtaining better results for the outlay.

I address myself particularly to those fish-culturists who are engaged in rearing
fishes to be sold for food, and to those who see the necessity for planting large fish in
certain waters intended to be stocked. The paper will have little interest for those
who dispose of their fish as fry. To the former class the data, if not the deductions,
must possess some value.

Nowhere in the literature of fish-culture obtainable at the general book stores
can the prospective investor find an answer to the natural question, How much will
it cost to raise a pound of trout? unless we except the statements made in the
concluding chapter of Domesticated Trout, a part of which was written twenty-two
years ago, and the remainder in 1890, statements which, I think, Mr. Stone would not
care to guarantee to-day.* In 1864 Mr. Francis Francis wrote:

Doubtless some kinds of food agree with them [trout] far better than others. But we know very
little on this branch of the subject. It is dreamland to us, with very little ascertained waking reality.
Few experiments of any note have been tried in the feeding of fishes, this being as yet almost untrodden
ground.

This remark is as true to-day as when written, thirty years ago, and stands as a
monument to the want of progress among American fish-culturists. I say American
fish-culturists, for fortunately the Europeans have progressed in this direction.
Because over two decades ago a fish-culturist, groping in the dim light of a closely
shuttered house illuminated by a single bull’s-eye lantern, killed his trout with a diet
of milk curd, and another expert, with as much (or as little) light in the house and on

*In the Transactions of the American Fisheries Society for 1892, Mr. F. N. Clark presents some
calculations on the cost of raising yearling fish, and in the United States Fish Commission Bulletin
for 1893, page 228, Mr. C. G. Atkins gives some similar data; but neither of them reduces the cost to
pounds of fish, without which, for the purposes of this discussion, the data possess little or no value.

289
F.C. B. 1894—19

290 BULLETIN OF THE UNITED STATES FISH COMMISSION.

the subject, killed his fry with the yolk of hens’ eggs, the law was laid down, ‘ You
must not use curd or hens’ eggs for fish food,” and these two really valuable articles
were placed on the blacklist. Unfortunately, with all our vaunt of being the most
advanced of the world’s nations in fish-culture, we are so conservative that it rarely
happens that an article which once finds itself on the list of prohibited foods receives
a second trial. As a matter of fact, one of the best experts in the world to-day, one
who makes the business pay a handsome return on the money invested, Sir James
Maitland, of Scotland, as far back as 1878 was using fifteen dozens of hens’ eggs
daily. Again, one of the State fish commissions west of the Mississippi River depends
largely upon curd as a trout food.* Their work will be shown to compare favorably
with that of other places where these cheap articles are interdicted.

Another article proscribed by one of the books on fish-culture is to-day almost the
sole food of one of the best-paying private hatcheries in America. These instances
are stated to show that the rules laid down in the text-books are not in all cases reliable,
having been too frequently drawn from a single illy conducted experiment. Scarcely
any of the writers have anything to say on the really important question, How much
food is required to produce a given result? Nowhere in the English books are data
and rules given which would enable one to calculate with any degree of exactness the
amount of food needed during a given period for a given number of fish. One impor-
tant use of such knowledge would be the calculating of a periodic supply of food for
some hatchery situated away from the lines of easy and cheap transportation. Should
the feasibility be demonstrated of the preparation, at the base of cheap supply, of an
artificial food to be preserved and shipped in large quantities by freight to off-lying
hatcheries, the question would naturally arise, How much will be needed during the next
six or twelve months? The early experimentalists contented themselves with saying
that such and such things made safe, cheap, and economical foods (in nearly every
case having reference to liver, heart, and lungs of animals), and that such and such
were poisonous to the fish, and quietly ignored the question of definite quantities.

The fact is that there is scarcely an article in the entire gamut from curd to horse-
flesh that may not be fed to trout with perfect safety. The questions are, or should
be: What amount per day of a given article will be needed to produce a pound of
trout within a given time? Is this amountof food beneficial or harmful to the correct
or normal development of the fish? If harmful, can it be rendered harmless by the
admixture of other foods? And, finally: Can the grower for the market find a profit?

In my Chicago paper it was stated:

There are among fishes, in common with other animals, several dietaries, some followed from a
matter of choice, some from necessity, and others from ignorance on the part of the attendant. They
may, for convenience, be thus classified: First, bare subsistence diet, merely sustaining life and
resulting in stunted, deformed fish, or starvation; second, healthy diet, promoting normal growth
and development; third, fattening diet, fitting for heaviest marketable weight; and, fourth, over-
fattening diet, causing a temporary or permanent suppression of the functions of the reproductive
organs, a partial or total destruction of the eyes, and inflammation of the intestines, frequently
resulting in death.

A considerable percentage of American fish-culturists are to-day confining their
stock to the first diet, either in quantity or quality of food, and are yearly producing
stunted or half-starved fry which, by courtesy, are called yearlings. Dismayed by
their own early experiences and those of the first experimentalists in feeding fishes,
they have not only stricken. article after article from the list of available foods, but

* Practical Trout Culture, Dr. Slack, page 123: “Curd is absolutely poisonous.”

FEEDING AND REARING FISHES. 291

have reduced the quantity below the point of healthy development. One of the early
writers has said, with every appearance of correctness, that if the fry are starved in
infancy they become stunted, the bones harden, and afterwards no amount of feeding
will cause them to expand sufficiently to permit of growth. Unquestionably, it is at
this stage in the rearing of fishes (the earliest feeding of the fry) that the greatest
amount of damage is possible and the most lasting hurt frequently done. It is the
most difficult stage in feeding and rearing, because it is at this point that intelligence
and fidelity are needed more than at any other time.

In the first feeding of fry it is not practicable to weigh the fry or their food so as
to instruct the caretaker as to the allowance of food; though after the fry have been
taking food for some little time it is possible to determine their weight, but it is
searcely probable that any except the most careful experimentalists will ever expend
the time and labor necessary. It is not likely that any better method for this deter-
mination will be devised than that of Mr. Charles G. Atkins, of the U. 8. Fish Com-
mission. His method is as follows:

The fish are first gathered in a fine, soft bag net, commonly one made of cheese cloth, and from this,
hanging meanwhile in the water, yet so that the fish can not escape, they are dipped out a few at a
time in a small dipper or cup, counted, and placed in a pail of water or some other receptacle. This
counting is generally preliminary to weighing, and in this case the fish after counting are placed in
another bag net, in which they are lowered several hundred at a time into a pail of water, which has
been previously weighed, and the increase noted. With care to avoid transferring to the weighing
pail any surplus of water, this is a correct method and very easy and safe for the fish.—( Bulletin of the
U.S. Fish Commission, 1893, p. 227.)

Mr. Atkins does not say so, but it would seem that he must deduct from the
increased weight the weight of the wet bag net immersed in the weighing pail.

Only judgment, experience, fidelity, and watchfulness on the part of the attendant
charged with the feeding will be found to answer at the time when the fish first com-
mence to take food; and unless these qualifications are employed the fish are either fed
to death or Starved. Some of the rules for feeding young fry would be laughable if it
were not for the memory of the helplessness of the fish. A rule at one hatchery is to
give them all they will hold; another acquaintance says keep them hungry all the
time. There are few happy mediums in practice. Years ago the idea was dissemi-
nated that any clever youth of ordinary capacity could safely be intrusted with the
care and feeding of fishes. Unfortunately the idea is not yet entirely eradicated.
They are short-sighted managers, blind to the principles of protection of animals from
cruelty, who leave this most important branch of the work in the hands of any except
the patient, intelligent, skilled workman.

Not all cases of semistarvation and stunting have resulted from the causes
mentioned—ignorance or fear on the part of the attendant. Cases have fallen under
my observation where, from various causes, the desired food, either as to kind or
quality, was not obtainable. Again, some fishes, particularly brook-trout fry, will
persistently decline the most dainty and delicately prepared foods. My own opinion
is that when a lot of fry is found acting in this manner the best thing the culturist
can do for himself is to get rid of them at an early day. They will never make fine
fish. * Several reasons have been advanced to account for this peculiarity on the

* In this some the question presents itself: May we not from this find a weaae reason
why in certain streams, presenting a fair abundance of food, we neyer find trout above fingerlings in
size. I, of course, suppose that in nature, as well as in artificial fish-culture, there are cases w vhere
the young, from some cause, will not eat, and it is more than probable that in many lots of fish
hatched naturally a large percentage never find any food, or find it too late to prevent or arrest the
stunting process, Once stunted, always stunted.

292 BULLETIN OF THE UNITED STATES FISH COMMISSION.

part of certain lots of trout, none of which are entirely acceptable. One writer *
asserts that at the time of the absorption of the sac the fry rises in search of natural
food, and if he does not find it he is compelled to take the artificial food prepared for
him, and the difficulty of adapting his stomach to this food results in a loss which
varies from 50 to 75 per cent.

Another fish-culturist says that they fail to assimilate the artificial food and die.
In passing, I hope to be pardoned for asking if the trout fry in the feeding troughs
offered artificial food when nature demands an aliment, even granting for argument
that they can not always assimilate it, are not in better position to fight the battle of
life than the trout fry in the streams, either hatched or planted there, where they too
frequently find an entire absence of food, for we know that streams are as frequently
barren of natural food for trout fry as the streets of cities are barren of food for
children. They live and reach a certain phase of maturity, but the product too often
falls short of expectations.

At one large establishment where the yearling fish have for a number of years
been abnormally small the trouble is thought to be due to prevailing low temperature
of water. This, in a measure, may be true, for it is a generally accepted opinion that
trout will not readily take their food on cold and cloudy days, and it is not unreasonable .
to suppose that the same cause would prevail in water of a constantly low temperature.
My own observations lead me to believe that, outside of the spawning season, properly
trained trout will eat as greedily during a snowstorm as during fair weather.

To whatever cause due, it must be admitted by every candid and impartial observer
that thousands of trout are annually raised which in size fall short of a commensurate
return for the time, interest, and money expended. I hope to show that a partial
correction is possible by the use of an adequate quantity of proper food. Private
fish-culturists, selling yearling fish at so many dollars per thousand, are more than any
others interested in making this correction. Information is beginning to be dissemi-
nated on this subject, and the purchaser, who a few years since was willing to pay
faney prices for that most meaningless and illy defined of all salable products—year-
ling trout—is now commencing to ask, ‘Of what size are the fish?” It seems to me
that it would be rational and fairer to all parties to establish a weight per thousand
and grade the prices up or down as the weight rose above or fell below the standard.

The importance of making such correction as above suggested is apparent, for if
at times we are stocking streams with stunted fish we are antagonizing one of the
hopes and claims of fish-culture, namely, the improvement of existing species. I
care not how carefully the breeders may be selected, how minutely all the essentials
of impregnating, hatching, and transporting receive attention, the resulting adult
fish will never be of large size and fine quality unless the fry have been properly fed;
and it is probable that if these fry have been stunted their progeny will be stunted.
The progressive and enlightened cattle-breeder looks closely to it that those individuals
which are to perpetuate his herd have received proper feeding and acquired full and
normal development; and it by chance a runt is among the herd, it is set apart from
the breeders. For the same reason we should not allow stunted fishes to enter into
the brood stock or into streams.

Against the danger of under feeding there should be little cause to warn the
culturist engaged in growing for the market. But because I have known such cases,

"Mr. Herschel Whitaker, Trans. American Fisheries Society, 1892, p. 96.

FEEDING AND REARING FISHES 293

the warning is distinetly given to the private fish-culturist. The greatest draw-
back against raising large trout in a given time (possibly surpassed by an improper
selection of breeders) is an improperly prepared food given in starvation rations to
the fry. “As the animal is, so to speak, made during its early age, and as during
this period its assimilating organs acquire their strength and their power of absorp-
tion, a young fish which is insufficiently fed not only grows very slowly, but will never
become a fine fish.”* Time was, and unfortunately is yet with too many, that canni-
balism was the only danger feared from fry on shortrations. Cannibalism was a very
good bugbear, but the true danger does not lie there, as it is always capable of correc:
tion in a short time.

The discussion of the second and third diets mentioned will be passed over for
the present and we will proceed to look at some of the ill effects of the fourth, over-
fattening diet, “causing a temporary or permanent suppression of the reproductive
orgaus, a partial or total destruction of the eyes, and inflammation of the intestines,
frequently resulting in death.” Nearly every fish-culturist of experience has seen
the two latter evils, “‘pop-eyes” and ‘“‘inflamed intestines;” whilst many have observed,
without knowing the cause, the retardation of the genital organs of the fishes. It
seems fairly probable that the causes known to affect the breeding of other animals
will in like manner influence the breeding of fishes. It is a recognized principle
among stock-breeders that an overrapid accumulation of fat is followed by partial
or total sterility, just as conversely a removal of the genital organs is always followed
by arapid accumulation of flesh. It would seem that the two processes are intimately
connected, and that an excess in either direction is at the expense of the other. The
complaint has not infrequently been made: ‘My fish grew finely, attained a remark-
able growth, and I fully expected a large number of eggs this season, but got very
few.” It rarely or never occurs to such complainants that the want of eggs was due to
the exceptionally fine growth. I have in mind a hatchery where the growth of brook
trout was such that many of them lost their eyes. Eggs were obtained in fair quan-
tity, but they were of such low degree of vitality that the season was counted a failure.
When these fish were marketed their quality was graded low. More than twenty
years previously Dr. Slack had noted a similar occurrence. In his book (Practical
Trout Culture, p. 121) he recounts the following:

A wealthy gentleman of a neighboring State constructed a well-appointed fish farm, with well-
stocked ponds. To his surprise, during the spawning season but few eggs could be obtained and but
a small percentage of these could be impregnated. We were consulted in regard to the matter, and our
first look at his fishes showed us plainly the cause of the trouble. The fishes were enormous, the
bodies greatly swelled, the whole cavity of the abdomen being filled with layers of fat. It appeared
that the proprietor had for over a year fed them twice a day all they could eat, and the result was, as
might have been expected, barren and unhealthy fish.

If ever artificially reared trout sell on a parity with wild trout—and there is no
reason why they can not be made to do so—it will not be the overfed, pop-eyed, liver-
reeking fish, which will produce the result. The danger of overfeeding is just as
distinet and as much to be avoided as that of underfeeding, though obviously the
evil effects will be less lasting and more restricted in results.

Let us now turn to the second classification, “‘ healthy diet, promoting normal
growth and development.” By healthy diet I mean not only the proper amount of
food per day, but a food composed of proper constituents. it has been before inti-

*C. Raveret-Wattel; U.S. Fish Commission Bulletin, 1887, p. 210.

294 BULLETIN OF THE UNITED STATES FISH COMMISSION.

mated that the writers on fish-eulture have been vague in dealing with this subject.
A few quotations will serve to make this point clear:

This quantity varies with the season, the quality, the quantity, and temperature of the water, and
other circumstances, and can not be stated definitely.—(Domesticated Trout, Livingston Stone,p. 236. )

Under favorable circumstances 5 pounds of meat food may be considered an equivalent for a
pound of trout growth, with 2 and 3 year olds. For any given quantity of 2 or 3 year olds 1 per
cent of their weight may be regarded as an adequate average daily ration the year round. Twoand
three year olds will double their weight annually, and ean be made to do so in the six months from
May to September by extra care and feeding.—(Domesticated Trout, p. 265.)

As to the quantity of food necessary for a given number of trout. This is difficult to give
exactly, as it will vary with the size of the fish and the season of the year, more being required in
moderate weather than when it is very hot or cold. For 1,000 three year-olds, about 5 pounds of liver
or lights per day.—(Trout Culture, Seth Green, p.51.)

When six months old a bowlful of curd, diluted with water, will answer for 1,000 trout fry.—
(Trout Culture, Seth Green, p. 38.) :

Since our stock of fishes attained its present size we have never been able to obtain as large a
supply of food as we would desire ; yet we find that our stock fishes, weighing in the aggregate about
a ton (2,000 pounds), thrive upon 50 pounds of lights a week, fed them in equal proportions on
alternate days. Asan average 50,000 young will require, when 6 months old and well supplied with
maggots, about a pound of chopped heart thrice weekly, though the amount varies greatly.— (Practical
Trout Culture, Dr. J. H. Slack, pp. 121 and 125.)

The quantity of food required is also large (for 2-year-old trout). Three pailfuls of chopped
horse are given daily to pond 15, which yields from 20,000 to 22,000 each season. The food is measured,
not weighed, but each pail holds 14 pounds.—(History of Howietoun, Sir James Maitland, pp. 73
and 74.)

When trout are raised in ponds of the dimensions I have given it is evident that little or no
dependence is to be placed on natural feed, such as flies and their larvie. Hence the necessity of
providing curds or liver and lungs of animals, at prices that will not cause too great an expenditure
for the value of the crop. I have found that the curd from the milk of one cow, which gave 14 quarts,
would feed bountifully 1,000 or 1,200 trout averaging five-eighths or three-quarters of a pound, the
smallest being 7 inches long and the largest from 2 to 3 pounds in weight.—(American Fish Culture,
Thaddeus Norris, p. 74.)

These quotations, carefully selected as the expressions of the five most generally
read English writers on fish-eulture,* show how little definite and accurate information
is recorded on the vital question of what should constitute a proper ration for a given
number of trout. Sometimes the number of fish is stated, sometimes their age, in one
instance the approximate weight is given, and only one English writer has had the
courage to approach scientific accuracy. But, alas! His formula is made to apply
only to fish 2 and 3 years old. The fry and the fish more than 3 years old are not
provided for.

The amount of food necessary for the maintenance in good health of a given lot of
fish must, as with any other animals, be in direct ratio to their weight, not their age.

* From writers of other nationalities the Pllawine quotations ms Ly nee ace ae

By experiments M. Lugrin has ascertained that a basin i ‘ may contain 20,000
young ‘fish from 8 to 12 months old, or 3,000 two-year-old trout hay ing an average weight of 250 grams
(i, or alittle more than one- half pound). These 20,000 young fish, or 3,000 trout, consume about

> pounds of small shrimps per day.—(The Piscieultural establishment at Gremaz, Fr rance; by C.
Ravoret.Wattel, Bulletin U. 8. Fish Commission, 1887, p. 209 et seq.)

At Howietoun it is on the weight (one-fiftieth of the living weight) that is determined the food
to be given, a method which appears more scientific and at the same time more practical than that of
feeding them without regard to age or development.—(Notes of M. Després, proprietor of the fish-
cultural establishment at Nantenil-en- Vallee, France.) [I havenot been able to find this formula of
one-fiftieth of the living weight anywhere in the History of Howietoun, and I suppose that M. Després
must have received the i information privately. Iam fully in accord with M. Despreés in his criticism
on the value of this formula. ]

FEEDING AND REARING FISHES 295

To state that 20,000 fish require three buckets of food per diem, without stating the
weight of the fish, is insufficient.

One of the at things to impress itself upon the attention of the student of this
question is the wide ana almost unaccountable variation in the size and weight
acquired by fishes of the same species under different hydrographic and climatologic
conditions. In some instances this variation amounts to 700 per cent. Compare the
weights of yearling trout raised m Colorado and Missouri. Who would say that
1,000 of the Missouri trout should be restricted to the same daily rations as a lke
number of like fish in Colorado? Elsewhere I have said that the Colorado trout could
not consume the allowance of the Ozark (Missouri) trout, and that the Ozark trout
would stunt or starve on the Colorado allowance. Better results will be obtained
when fish-culturists realize that fishes must be properly and plentifully fed in their
infancy and that their allowance of food, regardless of age, must be in constantly
ascending ratio with their increasing weight.

In the first study of this question I early found the lack of definite data in the
English writings. Correspondence was instituted to ascertain the general practice.
For convenience of comparison and study a condensed tabular statement of the
replies received is here presented :

Food and growth of trout.

Weight per 1,000 average
| Average | | year lings, in pounds.
Eleva- skeen daily ra- . , : Length | N |
es A tion |"), | tions, in| apa. -| Natural food | of aver-| | | a
pomae en doustion of above| *€™ | pounds, c haracter of) “present in |age year- ‘ EN a
Cartas sea ple per 1,000 A ponds. ling Ea 4 | 8
level. ape | yearling trout. | 4 | 5 - | 1A
ater.| “trout. |'s fe s a =
jg Gi a | nS =
| Pe Peja Pe a
—|—— |-— = | = ae
OF. | | Inches. |
Solway, Scotland......-..--- 150 | 5 Animal...-- Wes teacc soa 2.5to6 No tests made.
Howietoun, moctlnd: - -| S000 |550) ill. (ee ObLieeoe- (NS a eee B10 No tests made. | 10
Guilford, England. -.- a= ees 50.0 lviry smo --- do .- 4 to 10 E asec) Ho g
Haslemere, England. - 200 | 49-56 |...do ....|....- jittsebas -c] bees Gye Some ber 4 to 10
Vivero, Mexico - CEG || SP eS eee do -| 6 to 7
La Condesa, Mexico - 6, 500 do 7to 8 |
Cold Spring Ponds, N. HOON 85-761, [sae seer Saas do - 6 to 7
Troutdale Farm, Ark - -.| 600 sanim’ 12 ye; 7 to 10
Willow Brook, Minn ..---. 685 MAmimal®: al eee toe aan 5
Annin's Hatchery, Caleeo- 690 : 3. 25
nia, N. Y¥. :
Old Colony, Plymouth, Mass- 50 6 !
State Hatchery, Nevada..... 4, 660 6 No tests made.
State Hatchery, Nebraska. | 1,100 4.5 500}! 503) set 50 |
Duluth Station, U.S. F.C-.| 602 |... 5 70 | 80] 140) 80)
Leadville Station, U.S. F.C-| 9, 640 2.5 LO Serer eee 6)
Northville Station, U.S.F.C_| 600 4 to 6 |§60 | §80 |..-.. § 40
Wytheville Stat’n, U.S.F.C. 2,300 CO ean Gti) (ae ee eee c |
Neosho Station, U.S. F. C.| 1, 041 5.5 (| Gt) el bel ee |
|

*This weight was for fish 15 months old. My experiments in the spring of 1883 demonstrated that rainbow trout increase
their weight enormously in the fourteenth and fifteenth months. In proportion to the increase at Neosho the Troutdale
(Mammoth Spring) trout, at 1 year old probably weighed 82.27 pounds per 1,000 fish.

+ Mr. Annin says: ‘I have been very careful that my answers have been correct, and not magnified.”’

+ These answers are given as of May 1. I should say that the fish were yearlings past, and, judging from the length of
the fish, very highly fed.

§ Determined by the weights of specimen fish furnished to be cast for the World’s Fair at Chicago. Fish furnished by
the Neosho station for the same purpose ran 390 pounds for brook, 200 pounds for Von Behr, and 140 pounds for rainbow
trout (per 1,000 yearling fish).

296 BULLETIN OF THE UNITED STATES FISH COMMISSION.

The difference in locality, elevation above the sea, and mean annual temperature
of the water at the hatcheries is quite varied, but not more so than the daily rations
given. As for the results—the weight of the yearling fish—the data as given do not
admit of a too close comparison, some of the fish having been weighed at 10 months
old and others at 15 months old.

H owever, a study of the table does show that there is not only a decided lack of
harmony between the practice or methods of feeding followed at the various estab-
lishments, but that some are giving an inadequate quantity of food and others are
feeding far in excess of the needs. For instance: Leadville Station gives but 2 ounces
of animal food per day per 1,000 yearling trout, while the Willow Brook Hatchery,
of the Minnesota Fish Commission, gives eighty times as much to the same number of
fish. The quantity of food used at the Leadville Station is the smallest for which I
have any return, and it is not surprising to find that the fish grown there are smaller
than at any other hatchery in the United States. The next smallest is the Howie-
toun Fishery, of Scotland, where the ration is but two-thirds of a pound and the
weight of 1,000 yearling fish (Loch Leven trout) but 10 pounds.

When the very small size of the fish produced at Leadville first came under my
notice I was of the opinion that the extreme altitude of the place might in some way
(possibly by reason of the low temperature of the water consequent upon such great
elevation) be a controlling factor in producing such a slow growth. So firmly was
this idea fixed, that when the returns from the Mexican hatcheries were received I
requested a retesting of the weights. Not only was the weight as first given corrobo-
rated, but a sample of the food used was furnished. In that sample of food, ‘‘mos-
quitte” (Coriza femorata) was found the secret. It was a correct food, unfortunately
at present beyond the reach of American fish-eulturists.

Seeing, then, that the laws of the text-books and the general practice are so
variable, vague, and unsatisfactory, let us see what may be determined by analogous
reasoning from the established laws of dietetics for other animals.

Before entering upon this branch of the subject the reader is requested to bear
in mind that fish are cold-blooded and will never need—in fact, would be overburdened
with—as large a proportion of heat-producing foods as are needed by the warm-blooded
animals. Being cold-blooded, they have no body temperature to maintain, and so do
not require in so large a degree the rich hydrates of carbon needed by the warm-
blooded animals. Again, in small ponds, where the very largest per cent of the food
is supplied artificially, the work of the fishes in procuring a livelihood is reduced
to a minimum, and this will also be found a factor in determining the character of the
food to be supplied.

Animals for which laws of dietetics have been established most nearly resembling
the condition of fishes under domestication are cattle and men not at work. But no
perfect parallel can be drawn between these classes on account of the body heat to be
maintained on the one hand and its absence on the other. It seems that the average
man, passive or at lightest work, requires, according to the various authorities, solid
substances ranging from 20 to 44 ounces per day.* Assuming the average man to
weigh 130 pounds, the average of the allowance of the authorities would be 14 per
cent of the weight of the man. Dr. M. G. Ellzey, formerly professor of agriculture at

* Billings’s National Medical Dictionary, p. Xxx1x; Flint’s Text-Book Human Physiology, pp. 191,
192; Marshall’s Outlines Physiology, p. 899.

FEEDING AND REARING FISHES. 297

the Virginia Agricultural and Mechanical College, is my authority for saying that
“about 15 per cent dry food substances of the live weight is reckoned good keep for
mature live stock.”

It will be noticed that these allowances are for dry substances only. In an
attempt to make a comparison between the food allowances for men and cattle and
fishes the liquid substances have purposely been omitted. This is impossible of
calculation for the fishes. It will vary constantly with the character of the water,
the soil over which it drains, and the season of the year. It may roughly be assumed
that the sustaining elements of the coffee, tea, milk, etc., entering into the food of the
warm-blooded animals is replaced or compensated for by the insect life present to a
greater or less extent in or over most waters.

A study of the foregoing table and quotations giving the feeding methods followed
at the various fish-cultural establishments shows that the average of the food allowance
is 64 per cent of the weight of the trout. Last year I expressed the opinion that this
allowance was in excess of the requirements. This judgment was possibly hasty,
for it is to be noticed that in every instance the amounts are for wet foods; that is,
for liver, meat, curd, ete., in a more or Jess moist condition. The limited data at my
command shows that 1 pound of liver contains 24 per cent of dry substance; 1 pound
of horseflesh contains 23 per cent of dry substance, and 1 pound of curd contains 45
per cent of dry substance. From tests I find that 1 pound of mush made from ship-
stuff, or shorts, contains 28 per cent of dry substance. Hence we would have as the
average 24 per cent of dry substance given to fish as against 14 per cent allowed cattle
and men not at work. I think it will be admitted that this is too much. Notonly is it
contrary to analogy, but the experience of the Neosho Station has proven, to my
satisfaction at least, that it is in excess of all requirements. In the year which gave
us the highest degree of satisfaction the food allowance was 3 per cent wet sub-
stances, or 0.75 per cent dry substances. The trout at one year old. in that season
attained a length of 6 inches and a weight of 51.86 pounds per 1,000 fish. On page
300 will be found the schedule of the food allowance for these fish Curing each month
of the year reduced to a daily allowance per 1,000 fish.

From the foregoing, and from other observations, I am of the opinion that 1 per
cent of the live weight per day of dry substances will be found ample for trout, and
that an amount much in excess of this would be prejudicial to the development of
the fish. But it must not be supposed that this allowance of any or all substances
will be found to produce the desired result. As before intimated, the contrary will
sometimes happen. Man could exist but a short time on 14 per cent of his weight on
bread or meat alone. Not only this, but it has been pointed out that all food substances
vary, in the quality of their constituents, with the soil and season. No matter how
perfect the premises and how careful the reasoning, safe laws of dietetics, for man
or fish, will be found to require a great degree or elasticity.

Certain conditions are necessary to make an artificial food generality acceptable.
The supply must be convenient and certain; the cost must be such as not to entail
too great an expenditure for the value of the crop of fish; if should be a substance of
easy and rapid preparation, and, above all, the chemical composition, or proportion
of nitrogenous and nonnitrogenous constituents, should be in accordance with the
requirements of the fishes to be fed. In determining the food to be used at any
hatchery all of these factors must be considered in connection with the conditions of

298 BULLETIN OF THE UNITED STATES FISH COMMISSION.

the local market. The one element of food which has most generally been found to
fill these conditions is liver. It was probably the most fortunate accident in the
history of fish-culture that the circumstances of the first three conditions forced the
attention of the early culturists to liver. Its adoption may be viewed in the light of
a lucky accident, for in those days only the first three conditions were recognized, and
the fourth and most important condition, the proper combination of the elements
with a view to the requirements, was not considered by the fish-culturist. To-day,
unfortunately, it is but slightly understood. In substantiation of the view of the
value of liver the reader is referred to Prof. E. Wolff's table of percentage of nutritive
substances used as fish food.* From this table it appears that the chemical compo-
sition of liver (and hearts, lungs, and brains of oxen) more nearly approximates that
of insects and their larvee than does any other article of animal substance which has
yet come into use.

In Nicklas’s Pond Culture the study of the food for carp is detailed fully. Nick-
Jas deduces the formula that—

The most favorable proportion of nutritive substances in carp food is Nh: Nfr :: 1: 0.5 (or 0.6),
and that consequently food containing a good deal of nitrogen is the best and most profitable for carp.
The most suitable articles for food, therefore, are blood, horseflesh, fish guano, curds, meat dried and
ground fine, refuse from slaughterhouses, ete. All these, however, require to be mixed with other articles
of food containing less nitrogen, so as to restore the proper proportion of nutritive substances. On the whole
the food for the carp will have to be mixed very much on the same principle as that for cattle and
other domestic animals.

The italics in this quotation are mine. When it is remembered that Nicklas’s
formula was evolved to apply to the sluggish and slow-breathing carp, and that the
main subject of this paper is the active and rapid-breathing trout, the emphasis will
be apparent. The very largest proportion of the nonnitrogenous elements of food
required by the trout (and it will be very much in excess of that needed by the carp)
is for the purpose of respiration. It is for this reason that the otherwise excellent
article of liver, when employed alone, has not proven a perfect food for trout; and it is
partly from this reason that the Neosho method of mixing a large proportion of non-
nitrogenous substance with the liver has secured such satisfactory results.

If the careless reader is inclined to ask, Why is not a food well adapted to one
kind of fish (carp) equally well suited to another (trout)? I would remind him that
whereas man in the tropics needs but the seantiest quantity of fats and oils the
Eskimo requires 20 pounds of animal food daily.t It would be a serious error to
suppose that the food suited to carp is equally suited to trout, or that the food
adapted to trout living in a mean temperature of 55° to 65° would be the best for the
same fish in a mean temperature 30° lower, The very change in the rate of respira-
tion consequent on the change of temperature would, if the feeding was to be done on
the most economical and rational basis, entail a change in the character of the food.
A consideration of these facts led me some years ago to adopt a mode of feeding trout
which has since become known as the ‘* Neosho method.” The following description
of the method of preparing the food and feeding the fish at the Neosho station may
be of interest.

*Die Teichwirthschaft. From the Lehrbuch der Teichwirthschaft, by Carl Nicklas. United
States Fish Commission Report, 1884, p. 467. ‘Translated from the German by Herman Jacobson.
t Second Voyage for the Discovery of the Northwest Passage (Sir John Ross).

FEEDING AND REARING FISHES. 299
FISH FOOD AS PREPARED AND USED AT THE NEOSHO STATION.

The base of the food is composed of a mush made of “shorts,” or mill middlings.
To this mush, according to the kind of fish to be fed, beef liver is added in varying
proportions. The mush, unmixed with liver, is fed to some kinds of fish; mixed with
liver to others, and for some kinds is not employed. For making the mush we use the
best quality of shorts. The poor quality will not answer, because, like corn meal, the
mush made from it is too readily soluble in the water, dividing into finer particles
than the fish will eat. To obviate this we have the miller mix from 5 to 10 per cent
of poor flour with the shorts when it “runs poor.” For making the mush a large,
25-gallon farm boiler is filled nearly full of clean water, which is brought to the
boiling point. Shorts is then added, about 1 gallon at a time, and thoroughly stirred
in. Care is taken that the shorts does not become lumpy, but has a chance to cook
Im an even pasty mass, otherwise portions would be raw. After enough shorts has
been added to bring the mass fo a thick mush it is poured off into convenient-sized
pails and allowed to cool. It has been found advantageous to allow the mush to set
and harden thoroughly in the pails before using. To aid this process in the summer
the pails are placed in the cold running water in the hatching troughs. When
thoroughly set, well hardened, it is not so likely to too freely dissolve in the ponds.

To each kettleful, of 25 gallons capacity, 50 pounds of shorts are used, producing
166 pounds of mush. To each kettle of mush, as it is being made, three to four pints
of common salt is added. Whilst the shorts is being added to the boiling water the
mixture requires constant, vigorous stirring. For this purpose we use a wooden
paddle with a handle 4 feet long. Forty-five minutes is usually sufficient time in
which to prepare such a quantity of mush.

Four to five minutes will prepare a 10-pound beef liver for our work (except when
feeding young fry), by using a No. 22 meat cutter made by the Enterprise Manufae-
turing Company, of Third and Dauphin streets, Philadelphia, Pa. These machines
are provided with perforated plates for regulating the size of the cut of meat. The
perforations vary from one-sixteenth to three-eighths of an inch, being ample range
from smallest to largest fish, except for very young fry. When trout commence to
feed the liver is run through the one-sixteenth inch plate, and afterwards is forced
through a fine-wire screen. The screening of the liver is kept up until the trout are
large enough to swallow the particles of meat as they come from the machine. This
period varies with the development of the fish, the safe period averaging about the
third month of feeding. dl

The very young trout have never been subjected to the mush diet, though it is not
doubted that they could be induced to eat it, but they are started and kept upon a
pure beef-liver diet until they are thoroughly trained to congregate for their food.
When the fry have been on beef liver for about two months we commence to mix in a
little mush, and gradually increase the proportion of mush (and quantity of food) until
by the time they are six months old the mush and liver may be in equal proportions.
After that time the addition is made freely, so that when the fish are yearlings the
liver may be reduced to a minimum. HExigencies have arisen making it desirable to
economize on liver. At such times we have not hesitated to put the trout on a diet of
pure mush. They rise to the surface for this food, sometimes meet it in the air, and
rarely or ever allow a particle to reach the bottom. That the fish produced by this
diet are normal and healthy is beyond all question, and if evidence is wanted it is to

300 BULLETIN OF THE UNITED STATES FISH COMMISSION.

be found in the fact that their progenitors, spawning them at 2 years old, were raised
on the same diet. As yearlings these fish averaged 6 inches long and 51.86 pounds
to the 1,000 fish.

The adaptability of the stomach of the trout for various foods was tested by the
following experiment which I conducted at Neosho in 1892. On August 9, 1892,
12,000 healthy trout fry, which had up to that time received the same general treat-
ment and allowance of food as we usually give, were deprived of all animal or flesh
food. From that time until they were shipped, in February, 1893, not an ounce of
animal food was given them, and it is certain that the natural animal food which they
might have obtained was the very least. At the end of the year they averaged 4
inches in length, and an average 1,000 weighed 27.5 pounds. The fish were normal and
healthy, and though under the average for Neosho, they were above the average of at
least two American establishments.

The results to be obtained by this method are intimated above and a comparison
of results may be made by referring to the table on page 295.

As to the cost of this method the following table shows the allowance per 1,000
fish from May 1 (about the average time when fry are liberated as such) to December
31. IT might state that at the Neosho Station liver costs 5 cents per pound and mush
one-fourth of a cent per pound. These prices will, of course, vary with the locality.

Daily allowance of food, in pounds, per 1,000 rainbow trout (Neosho method and practice).

|

Period of time. | Liver. Mush. |

|
Murine Mayes. .----)-2---- 07 30
TUNG GO We eas ee = -10 -40
June 8 to 14........ 12 -48

June 15 to 21......- 15 60 |

June 22 to 28..-..-- cet -17 - 68 |
June 29 to 30........- nied -20 80
July 1 to 5 ---....-- = -20, .80
Tilly Gitow2ee css. Pilg We 30 _88
July 13 to 15... -- ae 25 1.00
July 20 to 26 .-.-. 27 1.08

July 27 to 31..-.-. 30 1.20 *

August 1 to 3i----- 30 1.20
September 1 to 30 =o. 1.40
October 1 to 31-.- -40 1.60
November 1 to 30 45 1.80
| December 1 to 31--- 5 2.00

Caleulations from the above table show that the food for 1,000 rainbow trout from
May 1 to December 31 (discarding fractions in the totals) amounts to 75 pounds
of liver and 300 pounds of mush, costing in the aggregate $4.50. The production
for this expenditure averages 50 pounds of trout. The value of this product varies
with the market, and is impossible of calculation for any specified period.

In a short article in the United States Fish Commission Bulletin for 1894, pp. 71
and 72, may be found some additional notes on the feeding and rate of growth of
trout in their second year at Neosho. By reference to this article it will be seen that
1,500 13-months-old rainbow trout made the remarkable gain of 241 per cent of their
weight in ninety days at an expenditure of 5 cents for food for each pound of trout
gained. At the end of sixteen months these fish were at the best marketable weight,
about one-third of one pound, secured at a cost, for food, of about 74 cents per pound.
of fish. This very rapid development of the trout during the latter three months is
not peculiar to Neosho. Senor Chazari states that the rainbow trout in Mexico attain
a weight of 160 pounds per 1,000 yearlings (!), and that “their development in the
latter part of the year is very rapid.”

FEEDING AND REARING FISHES. 301

The trout reared at the three hatcheries where the Neosho method of feeding is
followed, namely, Neosho, Mo., Wytheville, Va., and Mammoth Spring, Ark., are not
surpassed by any in the United States or in Europe. Only at the Mexican hatcheries,
where the cheap labor and peculiar conditions enable them to collect and supply the
natural food in sufficient quantities, are larger trout grown in the same period of time.
In 1893 the method was adopted by Mr. F. N. Clark, superintendent of the Michigan
stations of the U.S: Fish Commission.

Stubborn as are the facts which have been presented, the mixed diet for trout has
been covertly attacked on the ground that trout, from the nature of their teeth, are
carnivorous, and that it is contrary to nature to supply the domesticated trout with
other than a purely flesh diet. If our knowledge of dentition ever reaches any degree
of exactness it will show exceptions to the general law which will refute such idle
talk. It is a fact well known to all careful observers that—

Allour common fresh-water fishes eat vegetable matter. All of them seem to be fond of mulberries
and elderberries. Chubs, perch, eels, cats, carp (suckers) eat all grains and the meal thereof, whether
whole or ground. I believe that all of the rodentia are at times flesh-eaters. Herbivora often eat
flesh. Horses, mules, and cattle eat dry fish-serap freely. In the case of fishes which scarcely chew,
the dentition does not impede a change from one sort of diet to another. The lines which separate
between flesh-eaters and vegetable-feeders are scarcely so hard and fast as are generally thought.—(Dr.
M. G. Ellzey, ex-commissioner of fisheries of Virginia.)

The dentition argument against the mixed diet for domesticated trout is as
reasonable as that of the so-called school of vegetarians, who declare that because our
teeth resemble those of the vegetable-feeding apes more than any other animals our
most appropriate food is the fruits of the earth. I have before stated that the trout
we feed in our ponds are domesticated animals; that the jackal and the wolf are
carnivorous, but the domesticated dog sickens and dies when restricted to the only
food acceptable to his ancient progenitors. It is strange and unaccountable that the
average fish-culturist will persist in basing all his arguments for the determination of
the food for fishes under domestication upon the known habits and preferences of the
fish in a wild or natural state. All data relating to the habits aud food of fishes in
nature are of the highest value to the fish-culturist in determining the best conditions
for stocking streams, but they have no direct bearing upon what should constitute
their food under domestication.

Dr. James A. Henshall presented at the twentieth meeting of the American Fish-
eries Society (Washington, D. (., May, 1891) a paper on The Teeth of Fishes as a
Guide to their Food Habits. In the closing portion of this paper he says:

Thus, by observing the character and position of the teeth of fishes we have a sure and certain
indication of the character of their food, that is, of their principal and natural food. Of course,
there will be exceptions, but they only prove the rule. An herbivorous fish will occasionally swallow
animal food, while a carnivorous fish will sometimes swallow vegetable matter. * * * MTheyshould
be judged, however, by what they feed on mostly and habitually when situated so that they can
exercise their choice in the matter, for change of environment may involve a change of diet.

The last sentence of this quotation strikes the keynote of a mixed diet for trout
under domestication. Dr. Henshall would have come nearer to the facts had he said
that a change of environment (and it is a wide change from nature to domestication)
frequently demands a change of diet.

In Forest and Stream for November 18, 1893, over the siguature of Mr. A. N.
Cheney, is the following statement:

302 BULLETIN OF THE UNITED STATES FISH COMMISSION.

One of our best-known fish-culturists told me of his experience in rearing trout for market on
mammal food. He said he hauled his liver, ete., to the pond in a two-horse wagon, and carried the
trout to marketin a basket on his arm.

it is very possible that this misguided brother was one of the best-known fish-
culturists, but itis certain that be was not one of the knowing, for, while he was
employing two-horse wagon loads of liver to produce basketfuls of trout, other fish-
culturists were rearing them on a mixed diet of liver and mush for 8 cents and 10
cents a pound.

On page 49 of Seth Green’s Trout Culture is the statement that “ trout are car-
nivorous, and will not eat vegetables of any kind that we have ever tried.” This
statement, in exactly the same language, is repeated nine years afterwards on page
80 of Fish Hatching and Fish Catching, published in 1879 by Mr. Green and Mr.

toosevelt, commissioner of fisheries of New York. Mr. Green’s efforts in this direc-
tion could not have been very extended. The trout at Neosho are very fond of
crackers (stale oyster crackers), and I have frequently given the fry a treat of boiled
potatoes, forced through a masher (C. IF. Henis patent, which I regard as superior to
Sir James Maitland’s feeding spoon), boiled rice, pease, and beans.

There is a statement in Mr. Green’s first book (1870) touching the matter of feed-
ing which takes almost the form of prophecy. On page 47 he says:

Trout can be bred to any color by feeding and the use of proper ponds, and we believe that in the
future they will be bred to color, shape, flavor, ete., with as much nicety and certainty as the cattle
fancier breeds his animals.

At the Vivero hatchery, Mexico, the food consists largely of Gammarus, which
are there to be had only in a miry marsh. These impregnate the trout with a peculiar
muddy or marshy taste. To obviate this. trouble the shrimp food is suspended some
two months before the marketing of the fish, and nutmeg and ginger is added to the
other articles of food for the purpose of imparting an aroma or flavor to the flesh of
the trout. If the American palate objects to the combined flavor of nutmeg and trout
there is reason to believe that the objectionable article might be replaced by some
other flavor more acceptable. It is the writer’s opinion that such a condition as
prophesied by Mr. Green can not be induced by the use of a mammal diet solely; but
Senor Chazari has demonstrated the possibility of flavoring the trout flesh by mixing
vegetable with animal matter.

Should it be urged that trout raised on a mixed diet and intended for stocking
streams would, when liberated, by reason of a perverted nature and taste, be wnfitted
for natural food, I may answer by referring to the difficulty of retaining fowls which
have been hatched from eggs taken from wild nests. In infancy they live, thrive, and
fatten on the farm grains and kitchen scraps of bread and meat. One fine day they
leave for the woods or moors. Is it reasonable to suppose that they die for want of
the diet which served them so well in,infaney? The process of reversion from domes-
tication to nature is always easier than the change from nature to domestication.

Little as is known of the correct rations and best food for fishes under domesti-
cation, there is less known (and from the nature of things it will be more difficult to
determine) of the very important and high-power factors of range and space in deter-
mining the development and rate of growth of fishes. It is well known to every
culturist of experience that these are factors which should not be disregarded, and if
disregarded neither ‘extra feeding nor additional water supply will compensate for
the lacking elements. At first, range and space may seem to involve natural food,

FEEDING AND REARING FISHES. 303

and it must be admitted that to some extent this is so. But it is known that in pools
where the natural food is necessarily of a minimum quantity (for if the pool is at all
well stocked it can only be that introduced in almost microscopic particles by the
inflowing water) a given number of trout would be outstripped in growth by half the
number on the same rations per thousand fish. This has been ascribed to exercise,
freedom of movement, a larger quantity of oxygen per fish, and various other causes.

Other things being equal, it is certain that the temperature of the water and the
proportion of the pond or pool subject to renewal each minute, or hour, will be found
controlling factors of no small consequence. Of course, these elements may be, and
sometimes are, disregarded to the point of asphyxiation, but they are here mentioned
only as they influence development and growth. It seems certain that trout raised in
a high temperature grow more rapidly than those living in colder waters, and it is
more than probable that where the current is very swift too much aliment is demanded
in the work of living. It is true that in the natural home of the trout many fine fish
are caught in the swiftest waters. Because primarily they are fine fish they are able
to stand the exertion and strain of living in this swift water; and so, being in position
to catch and enjoy the abundance of natural food which the current washes down from
the sources of the stream, they become the finer. Again I would warn the reader not
to confound domesticated trout in pools with wild trout in mountain streams. Mr.
Livingston Stone lays stress on cold, sunless water and close confinement as dwarfing
influences on trout, and urges the desirability of an abundance of warm water, range,
and plenty of space in growing large trout.

The following notes on the feeding of other species of fish at Neosho may be of
interest :

Black Bass.—The black bass (Micropterus salmoides) decline a vegetable diet in
any form, and can not be made to eat it. When mush is sometimes mixed with a
considerable quantity of liver they will take it in the mouth, but quickly spit it out.
The same results have attended frequent trials with crackers, bakers’ bread, and dog
biscuit. They seem averse to vegetable diet, no matter how well disguised with a
mixture of meat. Ihave been unable to induce them to take artificial food except
liver, and it must be fresh and sweet. Of course, minnows or other fish have not been
tried, the effort being to overcome their natural inclination to eat fish. When the
liver, as it will occasionally in summer, becomes the least bit tainted the bass refuse
it. Sometimes they decline everything. This peculiarity of the bass is well known to
anglers.* In the Neosho ponds the bass rarely eat on nasty, raw days, but on pretty,
clear days they follow one around the poud, seeming to beg for food. The food of the
young bass was discussed in my paper, The Propagation of the Black Bass in Ponds. +

The Rock Bass (Ambloplites rupestris)—In the first efforts at Neosho to feed
these fish a small quantity of liver was daily put in their pond, but it is doubtful if
they ever swallowed any of it. Sometimes they would pugnaciously dart out and
take a small piece in the mouth, to immediately spit it out. Formerly every few days
a small quantity of liver was put in their pond to assist in breeding the insect life
which furnishes the largest and most acceptable part of their food. For two years
past no artificial food has been expended on the rock bass. Their pond, of only 9,000
square feet water surface, is well planted with Potamogeton and Hlodea, on which the
smaller crustacea breed in such quantities as to support from 10,000 to 12,000 rock

* Book of the Black Bass, James A. Henshall, p. 360. tU.S. F.C. Bulletin, 1893, pp. 229-236.
? I

304 BULLETIN OF THE UNITED STATES FISH COMMISSION.

bass each year without the introduction of any other food. Apart from any consid-
eration of the value of these fish, they are the cheapest boarders at the hatchery.

The Channel Catfish eat the mush greedily. During the fall, winter, and early
spring they were dormant, and did not come for their food. Such as was offered them
during this period sank to the bottom and remained unnoticed. At other times of
the year they rose to the surface and ate the mush ravenously, reminding one of pigs.
They are, as is well known among anglers, v ery fond of liver, it being a favorite bait
for them among the negro fishermen of the South. Very rarely we mixed a small
amount of liver with their mush*.

The Carp and its Allies.—The food for these fishes has received such excellent treat-
ment at the hands of Mr. Carl Nicklas that the reader is referred to the translation
of his Pond Culture, to be found in the Report of the U.S. Commissioner of Fish and
Fisheries for 1884. But I would state that in ponds not overstocked I have never
found it necessary to employ any animal diet for this class of fishes, though it is not
to be doubted that the limes of feeding laid down by Mr. Nicklas will produce the
most satisfactory results in securing the best marketable weight in the shortest time.

NATURAL FOOD.

The artificial propagation of natural food fer fishes reared artificially has received
the serious consideration of European fish-culturists, and several of them claim to
have reached the solution of the problem and to be now rearing natural food in any
desired quantities at a not extravagant cost. Foremost among these was M. Lugrin,
of France, a description of whose secret process may be found in the frequently
quoted article published in the Bulletin of the U.S. Fish Commission for 1887. The
hope was held out last year, in the meeting of the American Fisheries Society, that
the French Government contemplated purchasing the secret of M. Lugrin and throwing
it open to the publie use.

Mr. Thomas Andrews, of England, also has for some time past been engaged in
rearing natural food, but, from my understanding of his letters, his process seems to
consist in allowing the natural food, principally Gammarus and Limnea, to multiply
naturally in reserve ponds and transfer the surplus to the ponds containing fish.

The method of Mr. C. G. Atkins, of the U.S. Fish Commission, can scarcely be
called, in the strict sense of the term, artificial propagation of natural food.t I take
it that maggots are in no sense natural food for Salmonidie, and I think that the
method, because of its extreme malodorousness, will never be acceptable to the
attendant or the community in which the work is conducted.

Senor Chazari, of Mexico, uses natural food in considerable quantities, which, by
reason of peculiar environments and cheap labor, he is able to collect at the low cost
of 24 and 3 cents per pound. I understand that he neither breeds the insects after
the style of M. Lugrin nor uses reserve ponds after that of Mr. Andrews, but relies on
neighboring Swamps as a base of supply. The local technical name of the Mexican
food is “ mosquitte,” and in answer to my inquiries Senor Chazari wrote as follows:

It is a kind of aquatic insect, being produced in large quantities in our lakes pertaining to this
district, especially in that of Fercoco, and from which considerable quantities are collected every year,
mixed with larvie and other aquatic insects. It is utilized extensively as a food for singing birds. It
is aspecies of Coriza, the Coriza femorata. Itis veryrich in ‘‘azoid” principles (is are almost all insects),
and even more than others, and therefore is considered an excellent food for fish. I have preferred it,

“U.S. Fish Commission Bulletin, 1883, p.419; 1884, p.321; and 1886, p. 137.
+ Bulletin of the U. 8, Fish Commission, 1893, pp. 221 et seq.

FEEDING AND REARING FISHES. 305

in view of these highly estimable qualities, and because it can be given to trout without any mechan-
ical preparation, even to the smallest. Some 20,000 or 30,000 pounds a year are collected. * * * Its
only defect is that it keeps but for a short time. It rots, and is devoured rapidly by other insects
developed in it.

In the saine letter it is stated that rainbow trout at 1 year old, fed on Coriza,
attain a weight of 160 pounds per 1,000 fish. I know of no other place where
attention is given to the Coriza except the Neosho Station, where it is not used for
the trout but for the pond fishes, black bass, rock bass, ete.

Last year Mr. A. N. Cheney called attention to the methods of the Austrian, Carl
Elder von Scheidlin, who says: * ‘‘1, by following further on the lines of the French-
man, Lugrin, have solved” the question of proper food, ‘‘and have tested the solution
as good, cheap, and practically feasible.” Mr. von Scheidlin has proposed, through
Mr. Cheney, to make over his method of rearing natural food for use in the United
States, and correspondence is now going on to that end.

Up to the present time the only tangible effort of a European in the direction of
cultivating natural food for fishes which the American fish-eulturist can take hold of
has not been accomplished by a fish-culturist, but is the result of investigations and
experiments conducted by Dr. W. Kochs, of the University of Bonn, on the Artificial
Propagation of Minute Crustaceans. The results of this work appeared in Biolog-
isches Centralblatt, October, 1892, and on account of its exceeding value a full trans-
lation is offered on pp. 306-308 of this paper. Occasion is taken to recommend for con-
sideration, particularly of the pond culturist, the suggestion of Dr. Kochs to construct
insect-breeding ditches along the banks of the ponds, from which the infusoria and
crustacea may find their way into the ponds. Observation has fully convinced me of
the value of the hint given by Dr. Kochs of the fondness exhibited by Gammarus for
dry brushwood, and I might state that the same seems true of all woods in which
decay has commenced; Corizain particular seems to frequent half-rotted logs lying in
warm, shallow water, though I believe Gammarus prefers clean running streams. I
have found it most abundant in water of a temperature not unpleasant for drinking.

Translations of portions of reports by M. Chabot-Karlen on the fish-cultural
operations of MM. Durand, Binder, Després, and other culturists of France are sub-
mitted on pp. 309-311. I would invite attention particularly to M. Durand’s method
of propagating the Cyclops, and I am prepared, from my own observations, to unquali-
fiedly indorse his remarks as to the value of Potamogeton and Nasturtium as a shelter
for the smaller crustacea.

As before intimated, little or no systematic attention, except on an experimental
scale, has been given this subject by American fish-culturists; the only approach to
the European method of which I am aware being that at the private ponds of Mr.
Fairbank, of Illinois, and even there the effort is like that of Mr. Andrews.

One of the objections which has been raised to the employment of natural food
is the time and expense which would be involved in collecting enough for feeding a
large number of fish. To this I make answer: First, be certain how much food you
need to produce the best results. A comparison of the values of different foods as
determined by chemical analysis and as exhibited on page 295 will show that from 7 to
10 pounds of the artificial food may well be replaced by 1 pound of natural food. I
say well replaced, because if 1 pound will do the work why burden the system with
the useless 9 pounds ?

*U.S. Fish Commission Bulletin, 1893, p. 278.
F. C. B, 1894—20

306 BULLETIN OF THE UNITED STATES FISH COMMISSION.

EXPERIMENTS WITH ARTIFICIAL PROPAGATION OF MINUTE CRUSTACEANS.*

By Dr. W. Kocus, University of Bonn.

Within the last twenty years fish-culturists have become more and more convinced that the
knowledge and dissemination of minute crustaceans and other lower animals inhabiting fresh water
are of the greatest benefit to fishing. The growth of the young brood and the faculty of the full-
grown fish to increase under favorable conditions are in the first instance regulated by the facility of
obtaining good food, and this regularly and abundantly. Emil Weeger delivered an interesting lecture
on this subject at the International Agricultural and Forestry Congress at Vienna in 1890, which
was later published with illustrations showing ‘‘ strongly magnified representations of several species
of crustaceans frequently found in the waters of ‘central Europe and insects belonging to the family
of gnats, May flies, and dayflies, all serving as food for fishes.”

At the close of this lecture Victor Burda, fish-culturist of Bielitz, spoke on the same subject
and added, relative to the propagation of fish in large ponds, that these small infusoria were not only
of the greatest importance for salmou-breeding, as stated by Weeger, but also for carp-breeding; it
was a subject which would demand the greatest attention among experts, because it was known ever
since the well-known expert, Director Lusta, had lifted the veil behind which the question of the
nutrition of the carp had been screened for so long a time, that the principal food of the carps, like
that of the salmon, not only in its earliest stage, but also later, consists of animal life, and he asks
why the artificial breeding methods of the water fauna,as suggested by Weeger, should not be
adopted.

Mr. Burda then continues and points out some measures by which the propagator might exert a
beneficial influence upon the growth of this minute water fauna. Starting from the idea, and this
idea is correct, that the minute crustaceans live on infusoria, and that these infusoria again thrive on
plants in the process of decomposition and on animal life, he endeavors to supply the ponds with the
necessary and appropriate food. He says:

““The decomposed substance serving as food for the infusoria accumulates on the bottum of the
pond, and is also mechanically distributed in the water, giving it a muddy appearance. The substance
distributed in the water partly originates on the bottom, partly enters the pond with the new influx,
in which case it comes from the soil, near by or far off, according to the condition of land or water.
The more luxuriant and the more fertile the land the richer the ingredients washed into the pond. It
is, therefore, of the greatest importance to have the greatest amount of this muddy influx led into
the pond after a heavy rainfall.”

This 1s doubtless correct, but it is also a fact that this acquisition to the pond is gained at the
expense of the surrounding lands, because they are impoverished by the heavy rainfalls. Of course
considerable values in the shape of organic and inorganic substances wash from the fields into the
brook, from there flow into the rivers, and then into the ocean, and so would become lost if they
were not collected in the ponds and subsequently absorbed by the fishes. But a correct pond
propagation must not depend on circumstances; just as a certain quantity and quality of manure
must each year be supplied to the field to produce fair crops,sg the same action must be taken in
regard to the fish ponds. Dr. Kochs tried for a year to catch the crustaceans described on Weeger’s
plates and to breed them in glass vessels holding from 8 to 10 liters (1 liter is equal to 2.113 pints)
for the purpose of investigating their conditions of life. He found them only in puddles, which
received their fertilizing substance from the surrounding land or from animal cadavers. In one case,
in a puddle in a clay pit near Winterschlick, he found that dung particles had been washed into the
puddle from an adjoining sloping orchard, where numerous dung heaps were found. The consequence
was a luxurious vegetation and numerous crustaceans in this puddle, while in many other adjacent
puddles hardly anything living could be detected.

It is not essential to catch a great number, because they increase wonderfully. To obtain those
species in a perfect condition, which collect between the water plants, he used a pear-shaped pipette
holding 1 liter, having a long and strong, but narrow, neck, and on the other end, in the pear, an
aperture 1 centimeter wide. When, closing the narrow neck and placing the pear end of the vessel in
the water, the stopper is suddenly removed, the water will rush into the vessel, carrying with it the
small infusoria. It is not possible to catch nearly as many with mull netting, besides the latter is
unserviceable between the water plants, and it is difficult to separate the infusoria from it.

Dr. Kochs has prepared since June, 1891, a number of glass vessels as aquaria, in each of which he
placed all kinds of crustaceans. Some he kept at his private residence in the open air and during the

* Translated by H. H. Gerdes from Biologisches Centralblatt, Band x11, pp. 599-606.

FEEDING AND REARING FISHES. 307

winter in a warmroom; others he kept in the Pharmacological Institute in a room not heated, but not
exposed to frost; others, again, since January, at the Physiological Laboratory for Animals at the
Academy of Toppelsdorf, near Bonn, in a room exposed to all atmospheric changes. One set of the
aqnaria was prepared as called for by Weeger; that is, 10 cubic centimeters of garden soil were
placed on the bottom and soaked with liquid manure; on this was placed mud from the puddles
containing crustaceans, and on this, again, dry leaves of hazelnut and willow trees. The aquarium was
then filled up with water. Some filiform alge, Wolfia, and other small water plants had entered into
the aquarium with the mud. In the course of two weeks there developed in all the aquaria minute
crustaceans (shell insects, flea lobsters, water multipedes, infusoria, green alge), a felted mass of
filiform alge, and a thick cover of WVoljia. The warmer the aquarium the quicker and better was the
development, but the plant life seemed to prosper better than the animal life. By catching these
small crustaceans in proper pipettes it was shown that the quantity in the aquarium was less than in
running water.

Subsequent experiments proved that the majority of the erustacea were very easily affected by
even the smallest quantity of ammonia, sulphureted hydrogen, or free acids, as also stated by Weeger.
It is clear that only the most favorable conditions for the development of the crustacea in the aquaria
prepared according to Weeger are mentioned. Then comes a period, which passes quickly, develop-
ing a good deal of this animal life. Dr. Kochs tried to accelerate the increase by throwing in small
pieces of meat or dung, sometimes with more or less success, and to raise larger individuals, having
the most success with the water multipedes.

These experiments soon convinced him that water in which the erustacea grow well and increase
was too unclean for most fishes; moreover, the crustacea require warm and more or less stagnant
water, and can, therefore. only be raised in shallow puddles exposed to the sun and containing many
water plants, whereby it is clearly shown that the propagation of infusoria for fish food must be
entirely separated from the breeding of fishes. When attempting to breed both in the same vessel,
either the water fauna prosper and in that case the fishes can not live, or vice versa. He ascertained,
also, through special experiments, that the minute crustacea could hardly live in water most favorable
for the growth of microscopic plant life.

Mixing 0.1 liter of nitrate of ammonia, 0.1 liter of biphosphate of potash, anda minute quantity
of iron with the strongly ecaleiferous water from the city hydrant in Bonn, and adding a small
number of water plants, the water will soon turn strongly green and turbid at a temperature of
from 10° to 12° C. (50° to 54° F.), and becomes slimy on account of the alge. Daphnia and Cypris
will hardly grow therein.

His aim to first produce, in the proper manner, large quantities of greenish water rich in plant
life for the sustenance of the crustacea proved a failure. Still it is true that many crustacea live
on microscopic plants, but the most favorable condition of life does not tally with that of the plants.

The crustacea are only good in transparent and clear water; all the fine aquaria tested for years
contained large water plants, but also always clear water.

Later he experimented as follows:

To make the method to breed crustacea artificially practicable and feasiblethe material needed
must be easily accessible and cheap. If the breeding is done in special receptacles (reservoirs) it must
be done in such a way that it will be easy to get the infusoria clean when fed to the fishes. The fol-
lowing experiment led him to a procedure which in his opinion will prove successfui: Taking two glass
vessels each containing 10 liters of water (21.13 pints) and adding 100 grams (3.53 ounces avoirdupois)
of fresh cow manure without straw in such a way that in one vessel this manure is evenly distributed,
while in the other these 100 grams of manure are placed in a glass cup and covered by wire netting,
it will soon be observed, especially where the temperature is warm, that a strong decomposition takes
place in the first-mentioned vessel, a thick scum of bacteria is formed, the liquid turns light-brown
and smells strongly of musk and ammonia. Cypris and Daphnia may live, and even increase, in this
bad-smelling liquid, if the temperature is not too high, and under the described conditions. On the
other hand, there is hardly any smell in the second vessel, where the manure is inclosed in the cup.
The gases forming in the manure raise the cup, bottom upward, to the surface of the water, which is
soon covered with a scum consisting of numerous bacteria and infusoria. The outer side of the wall
of this cup, and also the bottom of the large vessel, is soon covered witha whiteslime, also consisting
of bacteria and infusoria. After some time only organisms are developed containing chlorophyl

green coloring matter of leaves or plants) in large quantities. Daphnia, Cypris, Cyclops, and many
other crustacea grow finely in such a vessel. The wire netting which prevents the cow manure from
mixing with the water is thickly covered with minute crustacea searching for food. As the water

308 BULLETIN OF THE UNITED STATES FISH COMMISSION.

remains nearly clear, it is somewhat easy to catch the animals, and one may so become convinced of
the phenomenal increase. :

Under the influence of water and warmth a vast development takes place of those numerous
microorganisms contained in the cow manure which absorb the undigested parts of the manure, and
which serve themselves as food for the crustacea. The manure gradually disappeared during the
months of May, June, and July. When these crustacea are fed to small carp or goldfishes a gradual
transformation of cow dung into fish is accomplished, almost without the help of plants.

The Gammarus pulex has lately frequently been found in large quantities between old bricks and
half-rotten brush wood in the Endenich Brook, near Bonn, without any cells containing chlorophyl
having been found in the water or mud. The water of the brook was muddy, because it contained the
waste and drainage of several adjoining villages. This relatively large crustacean grows splendidly
in an aquarium prepared with cow dung, as previously described, if a little dry brush wood is added.

Practically, it will be easy to produce this transformation of cow dung into fish, subject to local
conditions. The most advantageous way would seem to be to dig ditches along the banks of the pond
about 1 meter wide and 25 centimeters deep (about 40 inches by 10 inches) connected with the pond
by numerous narrow cuts. Perforated boxes or flower pots filled with cow dung are then placed in
these ditches and protected from the rays of the sun. When this shallow water is warmed by the sun
a great quantity of infusoria and crustacea will develop, which by the rise and fall of the water in
the pond are sucked into it. If the banks of the pond are low, the fertilizing substance will settle
there, thus enlarging the area for the breeding of the crustacea and forming a feeding-place for the
young fishes. ;

All these infusoria are especially sensitive to light. The ditches and banks must have old bricks,
brushwood, leaves, ete., for the protection of animal life. A luxuriant growth of water plants,
especially Jolfia, must be prevented, because it absorbs too much nourishment from the water; that
is, the nourishment is collected in the plant in such a shape that it is unserviceable for the purposes
of fish propagation. *

These breeding ditches must, if possible, be dry in winter, so that the frost may easily penetrate.
In that case the winter eggs of the crustacea, bedded in the mire, will develop better and more numer-
ously 1n the spring than when having overwintered in water. It would be very interesting, but very
difficult, to determine the causes of this peculiar process. Dr. Kochs exposed the mud of several
aquaria in an open box to the sun, to rain, and to frost by keeping it in the gutter of the roof of his
residence. By putting samples in glass vessels filled with boiled hydrant water and placing them in
a warm room, there developed within three weeks Cypris, Daphnia, and microscopic wheel animalcule,
especially Hydatina senta and infusoria. It is certain that the eggs had several times been exposed
to —10° C. (149 F.). At the end of May several samples of the same, now air-dried mud, were put into
water previously boiled, and in two weeks numerous crustacea had again developed. By drying a
large quantity of egg-containing mud in the fall, the proper food may easily be bred in the spring and
summer.

It must here be stated that the eggs will not stand a drying over sulphuric or anhydric phosphoric
acid. When that is done they all die, as has often been observed. This is mentioned because it is
frequently asserted that the eggsof the lower animals may live for one or more years in the thoroughly
dried mud puddles. Even mud, cleft and disrupted by the action of the sun, still contains several
parts of water. A total drying up of the eggs, therefore, does not take place in nature.

Dr. Kochs made special experiments with the Helix pomatia, and found that under the usual condi-
tions the moisture of the living animal does not dry up in a year, even ina warm room; moreover, as
soon as a dry crust has been formed around it, it loses the moisture only in artificially dried air, but
it dies before all the moisture is absorbed. The poisonous substances forming at the bottom of the
ponds by aslow decomposition of organic substances at such times of the year when there is no frost
are destroyed bythe plant life. These infusoria, and also the eggs of the lower animals, are frequently
threatened by an accumulation of those poisonous substances during such times in winter when this
process does not take place. Half-decomposed organic substances are loosened and made spongy by
the frost, and later on easily crumble or dissolve. Only the drying and freezing of the mud, there-
fore, can be recommended.

* I think it pertinent at this point to remark that Dr. Kochs’s warning against allowing a luxuriant
growth of water plants in the ponds has reference to his method of ‘transforming cow dung into fish
without the help of plants.” Ordinarily—that is to say, naturally—the vis or fertilizing strength of the
manure would go to making a Inxuriant growth of plant life, which in turn would be converted into
the low forms of animal life exhibited in the infusoria'and crustacea,.

FEEDING AND REARING FISHES. 309

REPORT BY M. CHABOT-KARLEN ON THE FISH-CULTURAL OPERATIONS OF M. DURAND,
AT THE SCHOOL OF AGRICULTURE AT BEAUNE.*

The anthor states that fish-cultural operations were commenced at the School of Agriculture
and Viticulture of Beaune in 1886-87, near the Bouzaize, one of the affluents of the Sadne; that there
were at the time no trout in the vicinity or in the neighboring rivers, and that if was necessary to
buy eggs. The first year 12,000 fry were obtained, which were divided into three lots. Two lots of
3,000 each were planted in the Ouche and Muzin: the rest were liberated in the Bouzaize or held in
confinement near the shore and fed on Cyclops and afterwards on Gammarus. The second year 17,000
fry were obtained; the two rivers above named received 6,000, the Vouge but 1,000; 500 were planted
in the Love, and the rest put into the Bouzaize, a part at liberty anda part inconfinement. At the
present time 18,000 fry are ready to be distributed. In three seasons 47,000 fry have been turned out.

In the Ouche, in which the trout were previously unknown, it is now possible to take them
weighing 400 grams (about 14 ounces), those that were put in first being 23 months old. M. Brossard,
director of bridges and roads at Bligny-sur-Ouche, says that numbers of them of this weight can he
seen in the upper parts of the stream. As to those1 year old, they have attained a weight of 100 grams
(about 34 ounces). Moreover, natural reproduction will commence next season, and the conditions in
this river are so favorable that its stocking by this method is assured, as the fish will be in condition
to spawn in December, 1889. In the Muzin the same results would have been obtained had it not been
for poaching. Nevertheless, in spite of this and of the devices of every kind that were employed by
the mills along the stream, the trout reappeared in the Muzin.

More or less similar results were obtained in the Bouzaize. Reared in captivity in receptacles
abundantly provided with aquatic plants, Potamogeton and cress, and fed with Cyclops and aquatic
larvie of every kind at first, and then with Gammarus, the trout gained in a year an average of 60}
grams (about 2 ounces). At this age they were not able to cope with the large pike that infested
the mill course at the head of the river; this was emptied and the larger ones taken out, only those
of the size of the young trout being permitted to remain. Now, at the age of 23 months, a great
number of the trout weigh more than 300 grams (about 104 ounces), The following are the weights
of some taken in the river: First, 365 grams; second, 360 grams; third, 280 grams; average weight,
335 grams (about 1i4 ounces). So that in a year their weight increased from 604 to 335 grams, a gain
of 2744 grams in twelve months. Natural reproduction may be expected to commence in this river
from December, 188).

The report also contains observations on the Cyclops (which are presented with a view to furnish-
ing the basis of a method for the rearing of these), the Daphnia, and the Cypris, with some remarks
on the monstrosities found with th: eggs of the trout and a statement of prices obtained for trout.

The Cyclops possesses an extraordinary fecundity, and reproduces at a temperature of from 8° to
10° G. (46° to 50% F. about). In winter they seek the bottom and hibernate in some sort, but on
capturing them and placing them ina high>r temperature their generative organs will be seen to
revive. Thirty-five degrees C. (95° F.), however, according to our experience, is the highest they
can resist. The best for hatching is between 20° and 25° C. (68° and 77° F.). At this temperature there
forms on each female every two days two egg-bearing sacs, or external uteri, wherein the eggs are
hatched. At the end of two days these organs become detached and fall to the bottom. ‘The number
of eges contained in cach may be from 16 to 32, but generally the number of young obtained is some-
what less. However, the eggs hatch immediately, and the young Cyclops which issue forth are almost
globular, haying but four feet and no tail. At the end of fifteen days they undergo a molting, the
tail appears and other feet form, and fifteen days after—that is, a month in all, the Cyclops are mature
and ready to reproduce.

With such fecundity, it can be readily nnderstood how numerous they become. Carbonate of
lime is necessary in th» formation of their shell. From the fact that they are found in abundance in
water infused with veyetable matter in decomposition, the water, nevertheless, not contracting the
least odor, it is supposed that they live on infusoria, and that, therefore, the means by which the fish-
culturist may have them at his disposal is to multiply in his rearing ponds aquatic plants. (Potamo-

* The report was published by the National Society of Agriculture of France, June 19, 1889. The
papers in this Appendix were translated by Mr. F. P. Fennell, of the U. S. Fish Commission; none of
them have been translated in full, only such portions being presented as apply to the feeding and
rate of growth of the fishes.

310 BULLETIN OF THE UNITED STATES FISH COMMISSION.

geton crispus gives the best results.) In this way the Cyclops will live and reproduce with the young
fish. By digging in a neighboring field one or more holes into which is introduced a smal) stream of
water and placing therein the Potamogetons and fountain cress (Nasturtium officinalis?) (this last
agrees with the Gammarus) a temperature will be obtained at which the Cyclops can propagate in
great numbers; and there will be at hand in abundance the best food that can he given to the young
fish. The fish-eulturist who possesses clayey land can undertake this without expense. In basins so
prepared it will not be long before confervie and vaucherias will be seen to form, which, after a while,
becoming decomposed, will take on a brown tint, and in the midst of which the little creatures will be
very abundant.

For collecting the Cyclops a simple net is used, similar to that employed by entomologists. This
lets the water pass and retains a multitude of animalcules, not only Cyclops, but the larve of gnats,
Hydrachnas, ete., of which the fry are very fond.

The rearing of Daphnia pulex and Cypris fusca was also tried. The Cypris, however, were found
to prey upon the young fish. Having been put in with the embryos of the carp, they were often
discovered to the number of two or three fixed upon the back of an alevin devouring it, notwith-
standing the efforts of the poor animal to shake itself free. It was, therefore, necessary to abandon
their use, and with regret, because their fecundity is certainly much greater than that of the Cyclops,
and they mature much more quickly. It1is believed that this fact is absolutely new in the history of
applied fish-culture.

Finally, attention is called to the great number of monstrosities found among eggs taken from the
trout at Vougeot, at the establishment of M. Peloux. These breeders were reared by M. Peloux and
eame from the same parents, and it is asked whether these deformities may not be attributed to
consanguinity.

REPORT BY M. CHABOT-KARLEN ON THE FISH-CULTURAL OPERATIONS OF M. BINDER,
PROFESSOR AT THE SCHOOL OF AGRICULTURE OF SAINT-REMY (HAUTE-SAONE).*

In this paper it is stated that during the three years that fish-cultural operations were conducted
at this school 100,000 tront were planted in the Lanterne and Moselotte; and that such good results
were obtained in the Lanterne that the young fish could be seen therein as numerous as minnows;
that those 14 months old weighed 8 to 16 grams (0.28 ounce to 0.56 ounce) with a length of 7 to 12
centimeters (2.75 inches to 4.72 inches).

REPORT BY M. CHABOT-KARLEN ON THE NOTES OF M. DESPRES, PROPRIETOR OF THE
FISH-CULTURAL ESTABLISHMENT OF NANTEUIL-EN-VALLEE (CHARENTE).t

This paper has reference to the notes of M. Després on rearing salmonide by artificial food. He
says that the development of the embryo especially attracted his attention; that it was between the
third and fourth day before the absorption of the sae that the alevin would become hungry and com-
mence to eat, nob seeking its food, but lying in wait for it; that six or seven days after it would quit
its hiding-place and attack its prey, snapping at it while in movement in the water. He then enters
into a deseription of the means to be employed for the protection and feeding of the young, and he
seems to have succeeded in his experiments if, as he says, he is able to guarantee the rearing of 90 per
cent. At Howietoun it is on the weight (one-fiftieth of the living weight) that is determined the food
to be given, a method which appears more scientific and at the same time more practical than that of
feeding them without regard to age or development. The choice of food largely depends upon enyiron-
ment. At Howietoun mollusks are used to atgreat extent, while at Nanteuil brains, blood, and Limax
satisfactorily replace these shore animals, of which the alevins are very fond.

* Published by the National Society of Agriculture of France, June 30, 1886.
t Presented to the National Society of Agriculture of France, June 30, 1886.

FEEDING AND REARING FISHES. ali

REPORT BY M. CHABOT-KARLEN ON THE VIEWS OF M. EMILE RIVOIRON ON THE
REARING OF TROUT BY NATURAL FOOD.*

M. Rivoiron says that the young trout do not take food except when it is moving in the water;
that they do not go to the bottom. Unless great care is taken, which is not always possible, failure
is certain in the use of artificial food on account of decomposition. Of the natural food M. Rivoiron
prefers the Daphnias. To rear these he says: Dig near the side of the stream two, four, or six basins,
from 10 to 12 meters (about 32 feet and 9 inches to 39 feet and 5 inches) long, by 2 meters (64 feet)
wide, and 1} meters (about 5 feet) deep, according to the numberof Daphnias to be produced. Clayey
soilis preferable, as the water with which the basins are filled will not quickly evaporate. In these
there should be placed during March, at the north end, because the basins should be dug as near as
possible from north to south, one cubie meter (about 14 eubie yards) of fresh dung (cow dung and
horse dung mixed).

Every day the water should be stirred until it takes on a light-brown color, without, however,
becoming tainted. On this point depends somewhat the success of the microscopic beings that
during the first days of April shonld be deposited there. At a temperature of 25° C. (77° F.) each of
these will give birth every five days to eight others, which in a few weeks will amount to millions.
They reproduce even at a temperature of 32° C. (about 90° F.), and sustain a temperature of —6° C,
(about 219 F.). The least shock will kill them en masse. Under no circumstances should the water
he disturbed, and they should be gathered with the utmost care. This gathering (a sort of skimming)
can be commenced at the end of April and continued until the end of September. It can be done by
means of a strainer, which should be brought gently to the surface. Before being given to the
alevins the Daphnias should be placed in fresh water, in order to rid them of the odor with which
they may be impregnated; otherwise they will kill the young fish. It is supposed that the ammonia
in the rearing basin is the cause. A basin should never be fished to the bottom, and eight or ten days
should elapse, according as the temperature will have more or less favored the multiplication of the
crustacea, before recommencing the operation. When giving them to the alevyins the same precau-
tions should be taken with the Daphnias as when collecting them, and it is essential that they should
be deposited in the water very slowly. A basin of the above dimensions will cost 35 franes, and will
furnish, from April to September, from 170 to 180 kilograms (374 to 396 pounds, avoirdupois) of
Daphnias. An aleyin so fed will weigh at six months 6 grams (0.21 ounce), with a length of 6 centi-
meters (about 2? inches).

*Made to the National Society of Agriculture of France, July 1, 1885.

312 BULLETIN OF THE UNITED STATES FISH COMMISSION.

BIBLIOGRAPHY.

(The following table contains a partial list of references to articles on the food of fishes, artificial
and natural, under domestication and in nature. The abbreviations R and B are for the Reports and
Bulletins of the United States Fish Commission, T for the Transactions of the American Fisheries
Society, and § has reference to miscellaneous publications, a list of which is given at the close of this
appendix. }

=a)
Subject. Author. a | Vol. Page.
= = | — | eee ne
Artificial feeding of carp..---.-.----------.- | Carl Nicklas......-.-- “ R 1882 1009-1031
cultivation of trout in Japan.....-.. Sekizawa Akekio-----. R 1879 646
Black. bass, food obaace o> noes eee een ae | Dr. J. A. Henshall. ---- eae Yel Lea Le ee 164 et seq.
LON se ie ce Aree Sie rset ESOS ten ee ea ie DISCUSSION -- 4s eee tk XX | 8
DOF eee eer sete ele eae tts ee eee ee Ree Ss eee ag | ee f 32
Carp and trout, cost of food. ...-........--.. | A. J. Malmgren....---- B 1883 | 378
artificial feeding ODS ete josece CarliNicklass=-=-425-ee R 1882 | 1009-1031
POC ert 6 Nae ee ene eee eee eee ea Dra vHessel aos ee ees R 1875-76 | 895
Carpigfoodi ot see teoerre eee. ee see caeine Pa Bile cant= = eee APR eee oes | 72 et seq.
DDO Mord a ee ee aoe eae aoe ene E (sr wh essellssssae eee R 1875-76 | 869
Be Seo Se Ree A REE ee ee eee CarliNickl asp eae B 1883 | 403
BARRA Ee Bae ae ee a eee eee ane ( GalWiaes00d] eee oe ee ane B 1883 | 245
ae ‘food of,,pond culture --_2_-.-2.._.....| Adolph Gasch ..-.. -..- R 1883 | 1143-1150
Bak Ro Fe ARO MOS ea ai ee SOE a ieee CarlNicklas t= -ce. eee R 1884 | 565-587
Gan ‘food aNGsh alts see sees he eee ee fae Hugh D. MeGovern-. Tt x 11-16
ID eee See Mes ae AS As, ee Sale AL Ome otters a en tere ue] XI 5-7
Carp and other fish, how to raise.........-.- Max von dem Borne - -- R 1883 1133-1142
food, in Guirorniae a wee: Robert A. Poppe -----. R 1878 | 665
trout and, manufactured food_.....-__. Drs C(O bHanz aaa B 1884 449 et seq.
Nicklas’s food discussed .......---..--. | Baron von Ki .-.--:---- B 1885 | 290, 291
Catfish and trout, feeding .-.--........----.. AGP: Gardner sees B 1883 | 418, 419
LeqkoOnicOnn) Mealsees ase eee eee Naman May ...--....-- B el | 137
bee a (| R. O. Sweeney -.-... ---- Je 67
OIG Ee. SSG ee tae jE onesie eee B | 1884 | 321
China, food! for diryineree. 256-2522 222 <5 oS el deta Ko pacha: = esse ee R 1873-75 | 546
Codfish eat herring spawn -.-.--!-...-...--- | Prof. G. OkSarsoo ee R 1876-77 639
LOOCUO fea Seen eee fee eT R 1876-77 | 710
Colorattactediby toads sae ene eee iT XVIII | 20
Costiofitish ood jsesce sean eee ee aoe = R 1872-73 | 771, 772
food for carp and trout --...-.....-.. B 1883 378
Crawilishtoodoncesees oa) oe sie tee we R 1876-77 | 782
DO Rae eee Sane oh = SR eG ss ot R 1878 584
LD) OF eee RRS” eek Peer R 1879 | 767 et seq.
Crustaceans, cultivation of, for fish food. _._. R 1878 | 555-575
Devicedortesdingstry. sears seen neon nee WwW. 0. ‘Ghanihes Bree es 40) XVII | 25, 26
Embryo fishes, Pop oh eeu! kane nico JepAGeRy der 222 aces B 1882 | 179-205
Expenses of food of fresh-water fish......_.... Veto Wik bel Gye mere a e- 3B 1884 73
Fish fed by lake dwellers..............-..-.- Chrlbeymerss- 55 sseee R 1873-75 | 583
foodsand! feeding ee. seen ese ne ee. Uppeemoltz seen oe R 1880 409-514
Bishi foodtof 2s 7st Seite ee ee Philo Dunning ---..--. db XV | 79-83
LOE ores ac See ee eee ae eee Eugene Blackford -.-- - lie ake XII 5-8
I Drier eRe he ene a en Vit ensene 2 eee eeee R 1879 | BAT
Fishes in confinement, food of .........-.-.-. Fred Mather=.... -2.-- fe aed VI! 67 et seq.
LOOU: Ofer caas stet iat eRe See ase eee HAL YNeLC heneve es: ae ea- | manly XXI 22 et seq.
Hood fish,andstishitogdiecesese neces. ce dole. che teen eee At XII 27-32
Food habits, teeth as a guide to............. Dr. J. A. Henshall _.... ee, ae 3.6.4 24 ef seq.
Fresh-water fish, expense of....-.........-.- Ji. Manley sae -see B 1884 73
FOOD Ofte). neh Foe aoe sl Sidney I. Smith-....... R 1872-73 | 708-709
ry d6Vvicewtortecdinp ema neene ee ane ae W. O. Chambers..-...- a XVII 25-26
Gadus) morrhtiaeeeeicas cece nee eee s Karl Dambeck.....-.-- R 1876-77 533
German fish, food and digestion.-............ Dr Pa eancritines=. se. | ee 1886 145 et seq.
Goldfish, Sood OPN Gases Lae ie Deutsch. F.Zeit........ fd 1878 679
DD Oe aia Ss een a eee aise ice Hugo Mulertt ...-.....| §3 oo eeee rece (LG t eG Beg.
Gouramt;foddiol-sss.- te oa eee eee eee Theodore Gill.....-...- R 1872-73 | 715
Grayling sfoodofes-<ate- ssanec coos ree wena Prof. J. W. Milner. ..-- R 1872-73 | 731
Herring; artiticial feeding --....-.222-...1... Hi Widseren 225-5: 5222 Re | Sys eeaeel 27,

FEEDING AND REARING FISHES.

BIBLIOGRAPH Y— Continued.

Subject.

313

Author.

(a)

Herrin ned sfood! of: .- = 2 -.42s-+-<=2-----2-<
Herring spawn eaten by cod
Lobsters, food of young --. -- aero
Mackerel, menhaden and, Hod Of seek ro
HOOG) Of emer ee Seer ces Soon ee

PPAIS hoodie =H he ene oS al
Mammoth Spring, Ark., food at... ..-.-.----
Manufactured food for trout and carp
DO eee ce ee ce aeceieeay
Marine animals, food of-.---- - see ies esos
Menhaden and mackerel, food riesiloe caeter.
Mississippi Valley, food of fishes of
Natural food, cultivation of

Gremaz (Ain), France.
Natural food, cultivation of ..........-... ----
report on piscicultural estab-
lishment of Piedra, Aragon,
Spain.
selt-reproducing food for fish. .
Oysters, food of fry and spat-----
Perch, diseased and healthy
PIKES tOOdtObs eee tor oe aoe ae ee eeeteh
Piscicultural establishment at Gremaz (Ain),
France.
Plankton estimates, some

WILMER erat et cies cases Woe eee |

Pollack, food of......----
Propagation of food for fish...-..---..-----.
Protozoa and protophytes - ..-.-.-.------..---
Protozoa and protophytes (2d edition)
Redahernm po wtoodsOt esses 0 cae eters
Report on piscienltural establishment of Pie-
dra, Aragon, Spain.

Salmon, Atlantic, food of........---.---..-.--

Sacramento, food of

Salmonide, in ponds, best food for. ......---
Salmonoids, raising in inclosed waters ------
Salmon, trout, and shad, food of
Nes shes: O00 Of - ac stain nanos See ee
Self-reproducing food for fish
Shad, food of

DN ode Seer SS cee ein Oe Soe cineee aa

Shad, food of young AEE rede pS eh

salmon, trout and, food of

Spanish mackerel, food of

Sturgeon, food of

Swordfish, food of
Do

Teeth, a guide to food habits ....-.---.------
Trout and carp, manufactured food for
Do

| R. Rathbun
| Prof. S. A. Forbes ------
| N. Wergeland
cultivation of crustaceans ---.--|---
piscicultural establishment at |

Axel Ljungman

| .
A.V. Ljungman .-

| M. E. O’Brien

ae tO

| Sidney I. Smith

ieeedo

Vi Henson. 2232 22-—~— $1

Hjalmar Widegren --.-)
Prof. G. O. Sars
A. V. Ljungman
Prof. G. O. Sars

M. -McDonald es eae
Rewkathborce oto eek }
G. Brown Goode -
R. Edward Earll-.-----
PAB IPs Hyerson----—=-
Dr Cx OM arZ ena eo eece
Garli Nicklas) 2 -=s----
Prof. K. Mobius.. ------

Magen cee ed

F. Muntadas

Frank H. Mason
John A. Ryder -----.---
Prof. S. A. Forbes -.----
DrGoG: Abbott —---<-
C. Raveret-Wattel

J. E. Reighard..-...---
Ernst Haeckel
ProtiG.O2Sars ---- ==
MEG Briens=--s!s-= 5
Prof. J. A. Ryder

Prot. G. Ossarts' <2. 5525-
F. Muntadas...--.--.---

Livingston Stone

German Fish Ass’n --- -
Director Haack
D. Barfurth
Sb Baris = ss
Frank H. Mason. .-----
M. McDonald... -.-.---.--
Dr. H. C. Yarrow
Sek pare eee
James W. Milner:
DBarfarth.. ..-- 22.2
R. Edward Earll
James W. Milner ------
G. Brown Goode. -.-----
A. Howard Clark.-.---
Dr. J. A. Henshall
Carl Nicklass.-2s-- ----
Dr. C. O. Harz

| Publi-
cation. |

BH HRW RHR RAR

HHH RRR RR RHR BRR BR

Vol. | Page.
1879 | 505, 506
1879 | 538
1873-75 | 148
1873-75 | 186
1876-77 | 609 et seq.
1878 | 181, 197, 216
1876-77 | 691
1876-77 | 639
1889-91 | 164
1881 | 41
1881 | 105-111
1880 =| 403

XIX | 46 et seq.
1884 449 et seq.
1884 | 453 et seq.
1879 485-489
1881 |
XVII
1878
1878 | 5
1887 207 et seq.
XVII 29-33
1887. 211 et seq.
1887 203 et seq.
1885 387-388
1888 485
1875-76 | 845
1887 | 207 et seq.
XXIT 112 et seq.
1889-91 | 565-641
1876-77 | 592
XVII 29-33
1881 236 et seq.
1881 755-770
1876-77 | 691
1887 211 et seq.
1872-73 | 371
1872-73 | 190
1875-76 | 808
1876-77 | 779 et seq.
1879 675-685
1873-75 | 735-759
1886 38-72
1887 | 203 et seq.

XII 33
1872-73 | 454-5
1872-73 | LVII
1873-75 | 367
1873-75 | 735-759
1880 | 403
1872-73 | 73
1880 329
1884 234

XX | 24 et seq.
1884 453 et seq.
1884 449 et seq,

ATAU UI

@ 002 860
314 BULLETIN OF THE UNITED STATES FISH COMMISSION.
BIBLIOGRAPH Y—Continued.
ch: Publi- | >
Subject. Author. Ta | Vol. Page.
Trout, catfish and; feeding.............------ Acse Gardner. == aes oe Bes | LSSs, 418-419
artificial culture in Japan ..-.-.-..---- Sekizawa Akekio....-. Re ost879 646
carp and, cost of food..--.--..-------- A. J. Malmgren....-.-. 3 1883 378
feedinp in confinement) .-----e——— =e eee nea = a= eee Noes i VIII 4-6
ID se easse Sanseosans soccescn ates N. Wergeland -..-.---- R 6 «61878 554
feeding in'ponds..--—-----——---- sSscinc: Dr? Broumme.-- 22-2 se 3 1884 330-331
Trout: foodoise. se ee eee eo et Coe Roosevelt & Green -...| §4 |--...----- 79-84, 130
D0t: cee eee ee eee Pee ease ee ee Bred Mather -.---.---- A XXI__ | 87-93
D0’: Baie SS eae cae ee ee @arlPeyrer’s-2sss-se x 1873-75 | 591
DOSER ee se Se ee toon Seth Green .-.-..-----. QiSr s|o2teeSeee 37 et seq.
Do) S28 2s ee BAS. Sach eee ae Me N@lark)s. 5-se5- T XXI 78
D0) teas oe cette c saci ees eae eee | Sir James Maitland....) §6 |.----.-.--- 61-264
DO yer see es bet ae oe see eee Santee ee eee | Win iPave 222i as- 3h XXII 71 et seq.
DD Ot eee St eke ee ence en. - see Peabo sy ersona sso a XIX 46 et seq.
Do) sets shee sess eee ee eee | Livingston Stone... .-- (tied Bees 228 et seq.
Dig eee: BS oe ee oe a eee ee ae | Thaddeus INGELISSS =< 2. < STS! 522 eect 73-68, 231
1D (i SA Pee epee wep ee So 2 om aed pe Bot ahi Jeb leh te el cee ee i SSID lee a eee 123 et seq.
Mroubtood, cost! O fae sae ee General discussion. ---- Wy .9.¢ 10 et seq.
Trout, rainbow, food at Baird!.--2--2----=--- | Livingston Stone --.---- R_ | 1880 618-619
salmon, and shad, food .-...-22_..-----} | D. Bar rfurth so Hee oe R | 1873-75 735-759
Transportation, feeding during..---.-------- Livingston Stone ------ R | 1873-75 | 394
Whatidoesyanish (cost ?i ie 5 = ae eee eee eee Christian Wagner ----. R | 1878 605 et seq.
Whitefish, adults, food of -.............--..- James W. Milner .----- R 1872-73 | 44
food) ofs-=As-2 ane ase eee AE SS | Frank N..Clark .22..2-- ® XVII | 67
ris earliest food) j5.2=.55--)-— = | Prof. S.A. Forbes --.--- Ri. || 1881 | 771-782
youns, feeding ss _ 9 see eee! James W. Milner .----- R 1872-78 | 32,57
Whitefish, young, food of-.--..2.-.-.------- Prank N. Clark .-.---:- R 1880 | 586
Wo its 2 225.555 sss eee gece osereeisi= 2 | Prof. S. A. Forbes -.----} B 1881 | 19 et seq.
Woteeet Ua: baaeyaec i os Ma Wes eee | W.O. Chambers . .----- B 1887 | 18
Winter: -food/of fishiip)eccee- 2-22 eee DrsCiCrAbbott 2. ose R | 1875-76 | 842
Utilizing water by fish-culture -.-.....-- =--.| Prof, B. Benecke--2-.-. R 1883 1101-1181
Yellowstone Park toodjim-.~..---.--s=-ee--- hata buns ss-=5-eee5 R 1889-91 | 138
Monn) fishes! foodsol: 2-22.) seer se ee eae Prot. 8. A. Forbes ------ | WI) eeeeics son: 10-19

DADA
_ ve Noe

aD
ao

§ 10.

The miscellaneous publications referred to in the preceding list are as follows:

. Book of the Black Bass, Dr. J. A. Henshall. 1881. Robert Clark & Co., Cincinnati.

. Practical Carp Culture, L. B. Logan. 1888. Youngstown, Ohio.

The Goldfish and Its Culture, Hugo Mulertt. 1883. MeDonald & Eick, Cincinnati, Ohio.

. Fish Hatching and Fish Catching, Seth Green and R. B. Roosevelt. 1879. Union Advertiser

Company, Rochester, N. Y.

. Trout Culture, Seth Green. 1870. Curtis, Moray & Co., Rochester, N. Y.
. History of Howietoun, Sir J. Ramsay Gibson Maitland. 1887. Published by J. R. Guy, secre-

tary Howietoun Fishery. Edinburgh University Press, T. and A. Constable, printers to
Her Majesty.

. Domesticated Trout, Livingston Stone. 1872. Fourth edition. 1891. Cold Spring Trout Ponds,

Charlestown, N. H.

. American Fish Culture, Thaddeus Norris. 1868. Porter & Coates, Philadelphia. Sampson

Low, Son & Co., London.

. Practical Trout Culture, J. H. Slack. 1872. American News Company, 39 and 41 Chambers

street, New York.

Proceedings of the Central Fish-Cultural Society. 1880.