234 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



pond. It is here Mill be found the minute Crustacea, daphnia, cyclops, and larvre.of 

 the gnats <>n which the young bass are to forage; and it is here, in this shallow water, 

 that they should he liberated. Not all dumped in at one spot, but slowly, carefully, 

 gently ladled in — scattered all around the margin of the pond. 



Construction of the nursery. — To attain the survival of the largest number of the 

 young bass, the construction and management of the nursery pond demand their 

 protection from enemies and the production of the greatest quantity of insect life suited 

 to their sustenance. It will be found advantageous to have a number of small ponds 

 rather than one large one. A good working-size will be a width not exceeding 12 or 

 15 feet, from 40 to 50 feet long, with a depth from 30 to 36 inches at the kettle. Where 

 the lay of the ground is such as to permit, it is recommended to have the nurseries 

 immediately adjoining and supplied by the same water as feeds the spawning pond. 

 Such an arrangement simplifies the operation of transferring the young fish, and at the 

 same time robs it of some of its dangers. As in all other ponds for fish propagation, 

 the supply and discharge for each nursery pond should be independent of any other. 

 They will be better when provided with bottoms sloping to the kettle. If the locality 

 is infested with crawfish it is advised to pile or otherwise protect the banks. The 

 entrance of snakes, frogs, and such enemies may be prevented by surrounding the 

 pond with finely-woven screen, or, better yet, boards let into the earth a few inches 

 and projecting 18 inches above the ground. 



Amount and temperature of water for nursery. — The proper amount of water for 

 the nursery is the minimum which will replace evaporation and seepage. In the 

 early age of the bass any approach to a current must be strictly guarded against, 

 for the young large-mouthed bass is not a strong fish or one loving a current. A 

 current sweeping through the nursery pond would be about as desirable as a colony 

 of snakes. Whilst these remarks are intended for the nursery pond they will apply 

 to the spawning pond, especially at and for some time after the spawning period. 



The young bass is able to stand any temperature, to which the sun raises the 

 water of the nursery. I have found the bass, just hatched, in water at 50° F., and 

 two months later they were thriving with the temperature at 80° F. The first week in 

 August, 1893, I found wild young bass iu stagnant water at 08° F. Caution should 

 be accepted here that bass grown in such very high temperatures are exceedingly 

 tender and impossible of handling and transportation until the approach of fall and 

 winter has gradually reduced the temperature and so hardened them. Moreover, 

 under such conditions they are more liable to the attack of parasites, both external 

 and internal. Whilst the bass has the ability to live in the extremes of 33° to 08° 

 F., there are limits which, if they can be secured, will be found advantageous. M. 

 Durand, of the National Society of Agriculture of France, states, as the result of his 

 experiments, that the cyclops reproduces best at a temperature between 08° and 77° 

 P., and that they can not resist higher than 05°. The young bass being so adaptable 

 as to temperature, it is a safe conclusion that the best temperature for them is that at 

 which their food best multiplies. 



Stocking the nursery. — How many young bass shall be put into a pond? This 

 very natural question is not easy to answer, for it depends upon flic size of the pond and 

 its capacity to produce food. With an unlimited quantity of food there would belittle 

 liability of overstocking. The secret how to produce natural food without limit is 



