198 BULLETIN OF THE UNITED S'I'ATES FISH COMMISSION. 



The first practical attempt in this direction was made in Belgium. 

 ]\rr. Thomas Wilson, United States cousul at Ghent, first suggested 

 placing catfish in the Scheldt, a river which, owing to the large number 

 of factories on its banks, does not contain many fish. It was presumed 

 that the catfish would be particularly adapted to the River Scheldt, be- 

 cause it had been sufficiently i)roved in America that this fish is not 

 much atiected by the refuse from factories. After consulting with Prof. 

 Spencer F. Baird, one hundred young catfish arrived at Antwerp in 

 November, 1884. By the advice of Professor Baird, these young catfish 

 were not immediately placed in the river, but first in the large basins of 

 the aquarium. It is only after these fish have reached maturity in the 

 aquarium and have spawned there that the young generation should be 

 transferred to the river. This was done ; and the young cattish received 

 fron-i America have provisional]}- been placed partly in a small pond in 

 the Botanical Garden at Ghent, and partly in the Victoria-Iiegia basin 

 in the same garden. The selection of the last-mentioned place we do 

 not consider fortunate, as the temperature of the water in this basin is 

 certainly much too high for these fish. At present there are in the 

 Amsterdam aquarium 45 catfish brought direct from 'New York, and 

 l)Iaced in a special basin with the hope that they will reach maturity 

 and propagate their species. At present these fish measure from 4 to 

 G inches in length. 



As regards the mode of life, habits, and propagation of these fish, the 

 following is known from the observations of Mr. John A. Ryder.* Dur- 

 ing winter the catfish lives at the bottom of the water, and prefers a 

 clayey soil, in which it almost buries itself. During the first fine days 

 in February some of these fish make their appearance, and in May they 

 may be observed in rivers and lakes in large numbers. They jjrefer 

 water which is muddy and does not have much of a current. Ko dis- 

 eases or i)arasites have been noticed in the catfish. Their only enemies 

 are bass, muskrats, and turtles. Mr. Ryder placed a male and a female 

 separately in a basin of the Washington aquarium. The female laid about 

 2,(K)() eggs in a shapeless heap, and left them immediately after they 

 had been laid. The male, however, acted verj' differently, and after the 

 eggs had been impregnated, did not leave them for a moment, and by 

 a regular movement of the pectoral fins caused a continual current of 

 fresh water to pass through the mass of eggs. After a week the young 

 tjsh slipped out of the eggs. On the thirteenth day after they had 

 been liatched, the umbilical sac had disappeared, so that two days 

 later the young fish eagerly took the food offered them, consisting of 

 small pieces of liver. It is very remarkable tliat the eight feelers round 

 the mouth begin to develop on the thirteenth day after the iish are 

 hatched, at which time also the last traces of the umbilical sac have 

 disa[)peared. 



" Soo F. C. IJulletiu for ld83, p. 225. 



