PREDATOR CONTROL 



Salamanders can be controlled in 

 artificial ponds by keeping the pond 

 dry until after they have deposited 

 their eggs. Because the salamander 

 returns to the pond to lay its eggs 

 shortly after the ice melts, the pond 

 can be safely filled in late spring. 

 In natural ponds the salamanders 

 can be controlled by removing the 

 large gelatinous egg masses before 

 they hatch. The egg masses are 

 usually formed on sticks or weeds 

 in shallow water, so they are easy 

 to find. 



Salamanders do so little harm in 

 sucker ponds that control is usually 

 not necessary. At seining time, the 

 dealer should sort out the sala- 

 manders as soon as possible because 

 they will gulp down large numbers 

 of minnows when held in such 

 crowded conditions. 



MUSKRATS 



The only appreciable damage 

 done by these animals results from 

 their burrowing in the dikes of 

 ponds. At times they can be seri- 

 ous pests, causing abnormal bank 

 leakage and slipping that result in 

 expensive maintenance costs. If a 

 minnow producer has difficulty 

 with these animals, he should con- 

 sult his Stat« conservation depart- 

 ment as to methods of control. 

 Most States have specific laws pro- 

 tecting the muskrat because of its 

 value as a fur-bearing animal. 



CRAYFISH 



In many places the crayfish (fig. 

 27) is considered a predator or a 

 nuisance in ponds, but in regions 

 where crayfish are used extensively 

 for bait, they may be an important 

 byproduct of minnow production, 

 or may rate separate ponds. 



In areas where crayfish are a nui- 

 sance in ponds, they can best be con- 

 trolled at harvest time when they 

 can be removed at no extra cost. 

 Every haul of the seine will bring 

 in large numbers of crayfish that 

 should be separated from the min- 

 nows as soon as possible to prevent 

 damage to the minnows from their 

 claws. If crayfish removal is to be 

 effective, the crayfish must be car- 

 ried away from the pond or buried, 

 as those thrown up on shore will 

 crawl back to the pond in a short 

 time. 



Figure 27. — The craylish is considered 

 an important predator in some areas. 

 ( Photograph courtesy of the Minnesota 

 Department of Conservation.) 



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