62 FISH CULTUEE 



eral years been engaged in the propagation of white 

 and yellow cat-fish on a large scale. It has, however, 

 been giving very little attention to pond-eonstruction 

 for this species of fish, simply using types of ponds 

 already built. The only uniform features have been 

 natural clay banks and clay bottoms without any 

 gravel coverings. The most pretentious ponds as far 

 as size and general utility are concerned are at Tor- 

 resdale Station, in Philadelphia. One is 150 feet 

 square; another is 275 feet long and 90 feet wide; 

 others are about 100 feet by 30 feet. The largest is 

 about six feet deep in the kettle, with an average 

 depth of a foot and a half all over the shelf. It was 

 formerly used for propagating sun-fish and bass. 

 It is excavated throughout and is fed by a small 

 stream. The first-mentioned pond is supplied by 

 water pumped into it from the Delaware River. 

 White and yellow cat-fish do equally well in both 

 ponds, and in 1908 the square pond yielded very nearly 

 200,000 cat-fish from about 300 brood fish of both sexes. 



Spawning and Care of Yoimg. — The spawn- 

 ing habits of the white and yellow cat-fish are 

 interesting. Although a nest-builder, the loca- 

 tion of the home and the habits of each are not- 

 ably different from those of the hlack bass. 

 Instead of selecting a stony or gravelly spot as 

 a small-mouthed bass would do, or a sandy 



