168 REPOET OF COMMISSIONER OF FISH AND FISHERIES. 



narrow near the middle, so that the general shape will be like a dumb- 

 bell with a very short handle. Across the narrow part is to be stretched 

 a screen of J-inch wire cloth, which will confine the spawners to the 

 deeper end of the pond, while the fry, following their instinct of 

 moving upstream, will find their way through the screen into thfe 

 upper, shallower end. This method would apparently not only save 

 much labor in transferring the fry, but obviate the risk involved in 

 handling thetn. 



If it is desired to hold the bass until they attain their full growth, 

 the fry are transferred to troughs or i^ools where they are reared in a 

 purely artificial manner — that is, tamed and trained to take prepared 

 food. For this purpose modifications in the shape and arrangement of 

 the spawning-pond are necessary, somewhat as described above for the 

 combination pond. The shallow part near the inlet has a long, narrow 

 neck and the general shape, where the ground permits, follows the 

 outline of a gourd. That part which resembles the handle is screened 

 ofit' from the remainder with wire netting, with a quarter-inch or less 

 mesh. The young fry, after the dispersal of the school, seek the shal- 

 low waters, which, warmed by the sun, at this time of year aflbrd rich 

 pasture of CyclopSj Daphnia, young Gorixa, and other small invertebrates. 

 Following the natural inclination of young fishes to head toward the 

 source of the water supply, they pass through the screen and collect 

 within the neck of the j)ond, where the food supply will be found to be 

 greater than around the margin. From this part of the pond the fry 

 have no inclination to retreat, and the parent fish can not follow and 

 devour them. 



TROUGHS. 



The ordinary horizontal trough in general use in trout-culture is well 

 adapted to raising young bass fry. A trough 12 to 14 feet long with 4 

 inches depth of water at 57°, changing 2 gallons per minute, will sup- 

 port from 3,000 to 5,000 black-bass fry, and twice or three times as many 

 rock bass will live comfortably under like conditions. For bass of 

 larger size, fingerlings and upward, vats or pools answer better than 

 troughs. The troughs can be so arranged that the water discharged 

 from them furnishes the supply for one or more pools. The shape, size, 

 and number of the pools must be regulated by the topography of the 

 land, though they should not be wider than feet, nor with a depth of 

 water greater than 2 feet, and either lined with plank or built of brick 

 or stone. Wire netting or guard-boards, projecting 1 to li feet above 

 the ground, prevent the entrance of -snakes and other enemies. As 

 with all ponds, provision is made to entirely empty one pool without 

 interfering with the water supply of another, and to have a good fall 

 from inlet to outlet. The length of the pool must be regulated by the 

 lay of the land, and, if long, it is advantageous to divide the pool into 

 sections, with movable screens of wire cloth for convenience in handling 

 several sizes of fish. 



