30 
THE NEW YORK AQUARIUM JOURNAL. 
FISH CULTURE AT THE AQUARIUM. 
The apparatus in use in the Aquarium for 
fish culture is of the latest and most approved 
pattern, and consists of a large wooden reser¬ 
voir divided lengthwise by a partition, in 
which are placed frames covered with a woolen 
screen which filters the water before it passes 
over the eggs. The hatching troughs, five in 
number, are placed with their heads abutting 
the reservoir and are supplied by brass cocks. 
In the troughs are placed frames covered 
with wire cloth, which, with the wood work, 
and in fact every part that the water comes 
in contact with, is coated with coal tar, which 
not only keeps the wire from rusting, but also 
prevents the jelly-like sap that always appears 
in new pine wood when under water, from 
exuding, while it also is a barrier to any 
\ egetable growth upon it. 
The eggs are laid upon these wire screens, 
of which several-layers can be used in each 
trough, thus increasing their capacity. Only 
two' troughs are in use at present and are 
filled with the ova of the California Salmon 
whicli were presented by Prof. S. F. Baird, 
the Commissioner on Fisheries for the United 
States. They were obtained from his Salmon 
breeding ranch on the McCloud River, Cali¬ 
fornia, in charge of Mr. Stone, the Deputy 
Commissioner. This variety of Salmon is 
called by Naturalists the Salmo Quinnat, and 
from its being capable of passing through 
water that iu Summer reaches a temperature 
of 80 degrees Farenheit on its annual migra¬ 
tion from the sea to its fresh water breeding 
grounds above, and which would kill its con- 
genor of the Adantic Coast, is more valuable 
than the latter for stocking all our rivers 
south of the Connecticut. Many millions of 
the eggs have been taken, hatched and dis¬ 
tributed by Prof. Baird in the past two years, 
but as it requires three years for this fish to 
reach maturity and return to the place where 
it was deposited, it is too soon to see the re¬ 
sults yet, though many young have been 
caught during the first year that they remain 
in fresh water. 
The eggs are obtained from the living fish 
by pressure of the hand upon the abdomen, 
and such is the delicacy of touch and knowl¬ 
edge of condition acquired by an expert that 
a fish is seldom killed by them, and Mr. 
Mather states that he has taken eggs from the 
same trout for five years in succession with¬ 
out injury to them. After the eggs are taken 
iu a pan that has been merely wet, a male 
fish is manipulated in the same manner over 
the eggs and in a few minutes after the addi¬ 
tion of a little water, the fecundation is com¬ 
plete and the ova is placed in a trough where 
it remains for three or four weeks, until the 
eyes can be distinctly seen and all the unim¬ 
pregnated ones picked out, when they are 
packed in a box with a layer of fine, living- 
moss, and a layer of eggs alternately until 
full—this box is then packed in a crate of hay 
or box of sawdust to keep it from changes of 
temperature and sent by express to any part 
of the world. The eggs of the California 
Salmon are the largest now handled by fish 
culturists, measuring nearly one-third of an 
inch in diameter, and as the eggs of any fish 
average about one size for each species, they 
are measured to find the number of thousands 
taken. 
It takes from forty to sixty days to hatch a 
Salmon egg, according to the temperature; a 
high one, say 70 degrees, hatching very quick¬ 
ly but leaving the fish weak. The best tem¬ 
perature is that of the spring water in which 
they are laid, perhaps, from 45 to 50 degrees. 
After hatching, the yolk of the egg remains 
attached to the abdomen for about thir ty 
days, and at first is so large that the little 
embryo cannot swim with it, but it is gradu¬ 
ally absorbed and when all taken up the 
Salmon takes food for the first time. This 
rule is good for all the varieties of Salmon 
and Trout. Some fish, as the Whitefish. and 
Shad, can swim as soon as hatched, although 
the sac is attached in the same manner. 
Later in the season the other troughs will 
be occupied by the Land-locked Salmon from 
Maine, a fresh water variety, the Lake Trout, 
the Brook Trout and the Whitefish ; these 
are all winter-spawning fish and hatch slowly 
on the trays. Shad eggs require an entirely 
different treatment, which will be explained 
in a future number of the journal. It is the 
intention of the Manage - of the Aquarium to 
stock some of the rivers with the fish hatched 
here, thus making it useful as well as in¬ 
structive, and a valuable adjunct to the Fish 
Commission, and to this end he has engaged 
the services of the well-known Fish Culturist, 
Mr. Fred. Mather, to superintend this JD epart- 
ment, for which he is well qualified by his long 
experience as a breeder of trout for a long 
period atHoneoye Falls, N. Y., and his work 
of Salmon and Shad hatching for the past 
three years for the Virginia, and United 
States Fish Commissions. 
This is one of the most interesting features 
of the Aquarium, both to the Naturalist, the 
Embryologist, and the casual visitor. The 
newly-hatched fish is/so transparent that the 
beating of the heart and circulation of the 
blood can be seen with the naked eye, and the 
development from the embryo to the perfect 
fish observed from day to day, and a wonder¬ 
ful transformation it is, for at first the little 
creature is as unlike the parent fish as a tad¬ 
pole is unlike a frog; the mouth which at 
first is only fitted to pass water to the gills is 
changed so as to take food, and the embryonic 
fin which, rising in the middle of the back, 
runs around the tail to the anal fin, is ab- 
80 ! bed, leaving the true fins more and more 
distinct each day. A few years ago Prof. 
Agassiz discovered that the Salmon had a 
second heart situated in its tail which was 
most visible at the third day and disappeared 
about the tenth. 
THE SEA RAVEN. 
Hemitmpterus Americanus. 
Closely connected by family ties to the Sea 
Swallow, is the Sea Raven, a fine specimen 
of which may be seen in table tauk d, and it is 
always surrounded by doubtful admirers who 
speculate as to the ownership of the wonderful 
tufts, “bobs,” and masses of disjointed flesh that 
seem to cover it, and the visitor is not rarely 
led to believe that by a system of inactivity it 
has been covered with a growth of aquatic 
plants and verdure. But they are all “ real,” 
and this fantastic ornamentation is the bona 
fide work of nature. The specimens in this 
tank were captured near Gay’s Head, Mass., 
and are there known as Sculpins, and make 
sad work with the lines of the patient fisher¬ 
man. It is subject to great variation of color, 
and the Aquarium will soon possess speci¬ 
mens, varying from the rich, russet brown to 
a br ight carmine yellow and red. They feed 
entirely upon small fish, but do not reject any 
morsel that their capacious mouths can cover. 
The Twin Salmon or “ salmonese twins ’.’ as 
the aquarium wag has christened them, are 
among the most interesting objects now dis¬ 
played in Mr. Mather’s department. The 
above illustration taken directly from the life is a 
careful representation of these queer little crea¬ 
tures as they now appear under the magnifying 
glass. The two bodies are attached to one sac, 
but each fish is perfect in itself. The con¬ 
necting vesicle is filled with oil globules,' arteries 
and veins, and it was expected that a microscopic 
examination would discover a diaphragm sepa¬ 
rating the circulation into two distinct systems. 
The closest scrutiny, however, fails to discover 
this wall and the circulatory systems appear so 
intimately connected that the blood flows freely 
from one body to the other, impelled, however, 
by two hearts. 
Mr. Mather is of the opinion that there is but 
little chance of their living after the absorption 
of the sac, for if they survive till that time the 
abdomens will still be joined by the membrane 
of the sac, and being thus compelled to swim on 
their sides, great difficulty will be experienced in 
obtaining food. In this instance, however, a 
careful system of artificial feeding will be adopted 
in case the pair reach an age when they will need 
such nourishment. From the extended obser¬ 
vations of Mr. Mather, it appears that these de¬ 
formities are quite frequent in the salmon family, 
which includes the trout, and in hatching one 
hundred thousand eggs, there may be from three 
to five hundred abnormal specimens, comprising 
crooked backs, twisted heads and tails, and in 
some instances two or even three heads are at¬ 
tached to one body. Several interesting exam¬ 
ples of these “freaks of nature " can now be 
seen in the display dishes at the hatching 
troughs, or will be shown to the visitor on in¬ 
quiry of Mr. Mather. 
GAR TisH. 
Lepidosteus Osseus Liu. 
In the Bonv Gar Pike we find a living rep¬ 
resentative of the old Ganoid race that are 
now only known by their impressions in the 
hardened sand-stones that tell of seas that 
rose and fell, perhaps millions of years ago. 
The fish is completely encased in a coat of 
smooth, thick, and rhomboiclal scales, an ar¬ 
mor equal to any foe. They grow to a large 
size, often exceeding four feet, and with their 
long bill armed with needle like teeth, and 
powerful fins, form no mean antagonist to 
the fisherman or sportsman. 
