EXPERIMENTS IN REARING SMALL-MOUTH 

 BLACK BASS 



BY ROBERT RIPBLE, IX CHARGE OE HATCHERY, MINOCQUA, AVIS. 



(Presented hy E. A. Blrge. Contrnhsioner of Fisheries.) 

 The following- pajjer records some experiments made at the 

 Minocqua Hatchery, Wisconsin, with artificial nests for rearing 

 small-mouthed black bass. These nests are made of Portland 

 cement, mixed one part cement, two parts sand, moulded in a 

 box twenty-four inches square, with rounded corners. They are 

 about three inches thick at the edge and one inch thick in the 

 center, where there is a hole one inch in dameter. They weigh 

 about fifty pounds each. The surface is covered with gravel and 

 stones, and sprinkled with sand. About fifteen to eighteen stones 

 of various shapes and the size of hen's eggs are set near the cen- 

 ter; outside of these come smaller stones, diminishing to fine 

 gravel at the edge. Great care is exercised in setting the stones, 

 so that the nest will appear natural and so that the nest will 

 drain as well as possible to the central hole. AVhen in use the 

 hole is blocked by a small stone. This prevents loss of eggs in 

 the hole and also makes the nest more acceptable to the fish. A 

 loop of strong copper wire is embedded in each side of the nest, 

 by which it can be easily handled. 



The purpose of these nests is two-fold: 1. To render possi- 

 ble some experiments in hatcliing eggs on trays after removing 

 from tlie nests. 2. To furnish better conditions for hatching 

 than are given l:)y the nests made l)y the fish themselves. 



I will speak of the second ]K)int first. It is well known that 

 no l)etter conditions for hatcliing the fry can be supplied than 

 are ott'ered by a natural nest of the Ijest type, on which the eggs 

 are properly spread by the female and which is properly guarded 

 and fanned by the made. But such conditions are by no means 

 always met. The stones in the center of the nest may be too 

 large, leaving deep and narrow crevices ; and whether they are 

 large or small the spaces may be such that the eggs which fall 

 into them cannot be properly fanned. 



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