SUCKER 



produce toxic ammonia just as the water- 

 bloom does, and because the algal mat 

 on the bottom may interfere with the 

 feeding activities of the sucker. 



Collecting the eggs 



Suckers and minnows that spawn 

 in running water are usually 

 stripped and the eggs are hatched 

 in jars. Taking eggs from the 

 sucker and fertilizing them is not 

 difficult, but considerable strength 

 is required. The sucker not only is 

 large, but it is one of the most active 

 and powerful fish for its size native 

 to our waters. On the upper Missis- 

 sippi and its tributaries, suckers lit- 

 erally swarm during May and June 

 over the shallow, rocky stream bot- 

 toms in swift water, as well as along 

 the rocky, wind-driven shores of 

 many of the northern lakes. 



The fish in these spawning runs 

 are caught with seines or traps and 

 are sorted. The ripe males and fe- 

 males are carefully put in separate 

 tubs of water and the unripe fish are 

 released for another day. If those 

 selected for stripping do not give 

 their eggs and milt freely under 

 light pressure, with the thumb and 

 forefinger moved downward over 

 the abdomen toward the vent, they 

 should also be released. Eggs 

 forced from the fish by heavy pres- 

 sure will not prove fertile. The 

 males mature somewhat earlier in 

 the season than the females, and the 

 bulk of them may have moved 

 higher up stream than the point at 

 w^hich the bulk of the females are 

 taken, resulting in a local scarcity 

 of males. Both sexes would be 



available, however, if the fish are 

 caught as they run up the stream 

 and are put into a suitable holding 

 pond until needed for stripping op- 

 erations. In any event, eggs should 

 not be taken unless a ripe male is im- 

 mediately available for fertilizing 

 them. 



The female is held over a damp- 

 ened pan into which the eggs are ex- 

 pressed (fig. 34). Immediately 

 after the eggs are taken, a male is 

 stripped of his sperm ; the milt and 

 eggs are thoroughly mixed by 

 gently swirling the pan. Four or 

 five pairs of fish may be stripped 

 into one pan providing each batch 

 of eggs and milt are thoroughly 

 mixed immediately after stripping. 

 After a lapse of 2 or 3 minutes, 

 water may be slowly added to the 

 pan and the stirring continued at 

 intervals by rocking the pan gently 

 to and fro, swirling the water. 



The milt can now be washed out 

 by frequent changes of water (fig. 

 35) . If the eggs have a tendency to 

 stick together in clumps, a cup of 

 muck or corn starch of the consist- 

 ency of bean soup should be added 

 as the eggs are stirred (fig. 36). 

 The muck or cornstarch is then 

 washed out with the milt. 



After being washed, , the green 

 fertilized sucker eggs are trans- 

 ferred to a tub to harden (fig. 37). 

 The tub is placed in cold creek water 

 and is shaded from the sun. Peri- 

 odically the eggs are stirred gently 

 and the water is changed. After 2 

 hours the eggs are hard enough to 

 withstand the rigors of transporta- 

 tion to the hatchery. 



71 



