MANUAL OF FISH-CULTURE. 167 



ants from tlie shores. Large ponds furnish wider range, and this is 

 desirable when fish are raised for market, but large spawning or 

 nursery ponds are not recommended; and if the object is to produce 

 large quantities of young for distribution in new waters small ponds 

 are undoubtedly better. 



At least one-fourth of the pond should be not over 1 foot in depth, 

 and this portion should be planted with pond-weed {Potamogeton) and 

 water-weed [Elodea or Anacharis) to facilitate the production and 

 growth of the minute animals, which furnish so large a part of the food 

 for the young bass. The remainder of the pond shmild have a gradually 

 sloping bottom, and consequent increase of depth to the kettle (or 

 draw-off), where the water must be at least from 3 to 6 feet deep for the 

 warm Southern States, and 12 to 14 feet deep for the l^orthern States, 

 to provide against the danger of freezing. In the middle third of the 

 pond water-lilies should be planted, preferably those having the largest 

 pads, such as the Nympliea alba; these plants not only furnish the 

 breeding fish a hiding-place from fish-hawks, but serve as sunshades 

 during the summer. It is not usually advisable to place large bowlders 

 in the ponds, as they are in the way of seining or netting, and furnish 

 an acceptable resort for crayfish. 



When the young, under the guidance of the parent fishes, are school- 

 ing, they may be collected from the nests and deposited in waters to 

 be stocked, or transferred to nursery-ponds. These ponds should be 

 constructed to afford young bass protection from enemies and to produce 

 the greatest quantity of insect life suited to their sustenance, and this 

 is better accomplished with a number of small ponds than with one 

 large one. A good working, size is from 40 to 50 feet long by 12 to 15 

 feet wide, with a depth of from 30 to 36 inches for the "kettle." 



Where the topography of the ground will permit, it is best to have 

 the nurseries immediately adjoining the spawning-pond, with the water 

 supply from the same source, so that there will be but slight difference 

 between the temperature of the shallowest part of the nursery-pond 

 and the surface water of the other. As in all other ponds for fish 

 propagation, the supply and discharge for each nursery-pond should 

 be independent of any other, and the bottoms be made to slope toward 

 the "kettle." The young large-mouth bass is not a strong fish, and 

 currents in the spawning and nursery ponds should be avoided for 

 some time after the spawning period. 



If the locality is infested with crawfish, it is advisable to pile or 

 otherwise protect the banks; and the entrance of snakes, frogs, and 

 such enemies may be prevented by surrounding the pond with finely 

 woven screens, or, better yet, boards let into the earth a few inches 

 and ])rojectiug above the ground. The pond should be supplied with 

 the acjuatic plants previously mentioned as desirable for the shallow 

 parts of the spawning-jwnd. 



A 1)1 an has been suggested, which combines the features of a spawn- 

 ing and nursery pond, by constructing one comparatively long pond, 



