41 



2,4-D has very little effect on fish and other aquatic 

 organisms. 



Special considerations in the propagation of suckers 



Preliminary studies on the propagation of suckers 

 for use as bait, conducted by the Institute for Fish- 

 eries Research, Michigan Department of Conservation, 

 have led to development of the following methods: 



Sucker eggs are commonly obtained by stripping ripe 

 fish (p. 28 ) or by collecting fertilized eggs from lakes 

 and streams where natural spawning has occurred. 



In many lakes, suckers are known to spawn along 

 the wind-swept gravel shoals, where the eggs tend to 

 concentrate inshallow water as a result ofwave action, 

 and can be collected with scap nets. In streams where 

 suckers spawn on gravel riffles, the eggs can be col- 

 lected by stretching a fine mesh net across the stream 

 below the nesting area. The gravel in the riffles is 

 agitated to dislodge the eggs, which are then washed 

 downstream into the net. 



In collecting sucker eggs, it should be remembered 

 that these fish do most of their spawning at night and 

 that the most opportune time to collect would be on the 

 following morning. Repeated collections are usually 

 necessary to obtain a large quantity of eggs. After 

 each collection, the eggs should be washed through a 

 1/4-inch cloth screen to remove the larger debris and 

 egg clusters and immediately placed in a hatchery jar 

 at the rate of 3 quarts of eggs per jar. The flow of 

 water necessary for successful hatching will vary, 

 depending upon the number of eggs in the jar, but will 

 generally range from 1 to 3 gallons per minute. The 

 water temperature should range between 50. and 60 F. 

 During thehatching period, each j ar in operation should 

 be attended once daily. The fungused eggs (white in 

 appearance) will collect on the top of the egg-mass, 

 forming a collar which can be siphoned off into another 

 container. If any clusters of eggs appear, the whole 

 contents of the jar should be washed through a l/4-inch 

 mesh cloth net and the clusters removed or the eggs 

 separated. 



When the eggs become eyed (a moving embryo visible 

 within the shell they should be removed from the jars 

 and placed one to three layers deep on screened trays 

 located either in a hatchery trough containing running 

 water or in a pond scheduled for stocking. If the eggs 

 are to be incubated further in the hatchery, the trays 



