SOME IMPORTANT BAIT FISHES 



I'^iGURE 34. — A female sucker is stripi)ed 

 of its eggs. (Photograph courtesy of 

 the Minnesota Department of Con- 

 servation.) 



Artificial hatching 



At the hatchery, the eggs are 

 transferred to Meehan hatching 

 jars (fig. 38) , Usually 2 or 3 quarts 

 of eggs are placed in eacli jar, and 

 the water is adjusted so the eggs are 

 in constant hut gentle movement 

 tliroughout the lower portion of the 

 jar. For best results, the water 

 shoukl contain sufficient dissolved 

 oxygen for the eggs, but should be 

 free of air bubbles because the bub- 

 bles adliere to tlie eggs and carry 

 them up and out of the jar. Lengtli 

 of hatching time depends on tem- 

 perature of the water. Eggs will 

 hatch in 4 to 6 days in water warmer 

 than 65° F., in 10 to 15 days in 

 water of 50° to 60°, and not at 



all in water colder than 50°. Min- 

 nesota hatchery operators prefer to 

 start the eggs at 50° to prevent 

 clumping, and then increase the 

 temperature to 55° or 60° for hatch- 

 ing, if possible. In some States, 

 the water from lakes and streams 

 reaches optimum temperature in 

 time to be used in the hatching 

 battery. 



Fortunately, sucker fry stay in 

 the jars after hatching, and do not 

 swim out with the water until they 

 are about 5 to 10 days old. Conse- 



FiGURK Hry. — The milt is washed away 

 with frequent changes of water. 

 ( Photograph courtesy of the Minnesota 

 Department of Conservation.) 



72 



