The Washington times., 1903-06-07
HOW YELLOW CATFISH
RAISE THEIR FAMILY
Breeding Habits Observed
by Fish Commission.
UNIQUE METHOD OF NESTING
Male on Guard While Process of Build
ing Is Going On-Solicitude in
Watching Over the Eggs.

written an interesting paper on the
breeding habits of the yellow catfish.
The paper is of interest in connection
with the attempt to restore the catfish
to its former position as one of the most
plentiful fish in the Potomac near Wash
1ngton. or late years its numbers have
been decreasing, and but little has been
done to replenish the supply by arti-
fetal breeding, because the breeding
habits were not known.
On July 8, 1902, two yellow catfish in
the Commissions aquarium indicated by
their actions that the female was about
to spawn and from that time until the
operation was completed they were kept
under constant surveillance. The aqua
rum was five feet long, sixteen inches
wide at the bottom. and eighteen inch
es high, the posterior wall inclining
obliquely backward. SO that at the sur
face of the water the tank was two feet
four inches wide.
Making the Nest.
The first move made by the pair was
70 withdraw to one end of the tank by
themselves, the male keeping other fish
away. Then began the nest making
The bottom of the tank was covered to a
depth OF one and oneh half to two inches
with gravel from one-half to three
quarters of an inch in diameter The
stones were removed by carrying them
away in the mouth and dropping them
with slightly explosive force. AS
rule the fish swan in a vertical posi-
ton while removing stones, but at other
times they carried the pebbles UP some
distance from the bottom and blew them
out The removal OF finer sediment was
effected by quick lateral movement of
the body, which caused a whirl that lift
ed and floated the finer particles beyond
the nest In one night of nest building
they removed all the gravel from over
one-third feet on the slate floor, upward
of gallon of stones being transferred
as described
No Use for Gravel.
pint of gravel was scattered over
the nest, but the fish removed ii in q
few minutes. The gravel-regarded By
bass and other fishes as desirable ma
terial for the bottom of beds-may be
removed by the catfish for two reasons:
To have clean place for the eggs and
young, SO that they may be better guard
ed and asitated. or to provide g smooth
place on which to rest and against
which to rub the abdomen
Twenty years ago catfish were album
dant in the Potomac. Piscataway Creek
marshes were a favorite place Tor them
TO spawn, and large numbers were taken
each spring and summer. The fish at
that time OF the year were found in
shallow water occupying depressions in
the muddy bottom, with most or all of
their bodies concealed in an excavation
extending laterally from the rounded de-
pressions. The authors are inclined to
believe that the fish were brooding, but
have not had an opportunity in late
years to examine them critically
With the pair in the aquarium, two
days interviewed between the beginning
OF nest making and the laying of eggs
During most of the time they rested OF.
the bottom. with practically no body or
fin movement except at intervals AT
frequent intervals the female com
pressed her distended abdomen against
the smooth slate bottom, which was
obviously for the purpose of loosening
the eggs.
Laying the Spawn.
On July ) theseggs were deposited in
four separate aggiutiaated masses en-
the slate bottom The masses were of
nearly uniform size, about four inches
long, two and one half inches wide, and
half an inch thick The eggs were one
! transparent, and of pale yellow color
Their number was estimated at 2.ceG.
| Fully 80 per cent of the eggs hatcned
! into norma! FRY.
| During the entire Matching period
! both parents were incessant In their eff
! forts to prevent the smothering of The
! eggs, to keep them clean, and to guard
( against tntruders. The eggs were con-
stantly agitated and aerated by a gentle
! tanning motion of the lower fms and
/ foreign particles, either on the bottom
| or In the water, were removed in the
mouth or by the fms. The most strik-
ing act in the care of the eggs was the
/
mouth and blowing them out again, this
being repeated several times with eacn
! cluster before another lot was treated.
The male assumed practically all the
work of guarding the nest, attacking the
! hand of the attendant who fed the fish.
and rushing at sticks introduced into
| the aquarium.
Eating Their Offspring.
| Until six days old the fry remained at
the bottom in q densely packed. wrig-
CLING mass. By the seventh day they
were swimming actively and all collect
ed in school near the top, where they
remained two days. after which they
scattered and did not again school
The very young fry were also taken
in the mouth and blown out by the
parents, especially those fry which nae
become separated from the main body.
| This parental solicitude was occasional
! ly disastrous, as II was noticed that
some OF the fry which went in the
| mouth never came out. but helped 10
make a meal for the cid folk. When
twelve days old 1,50o of the fry were re-
moved to another tank, where 1000 81
| them died from some unknown cause.
| The Others thriyed and are still at th's
| Communication building ha fry LEI