MILKER FISHERIES OF THE GREAT LAKES. 75 



argenteus Kirt. , wliicli is found very frequently attached to the skin. The 

 circular scars and raw sores sometimes found upon the sturgeon, and 

 attributed to this cause by the fishermen, are correctly accounted for in 

 this way. It is probable that their natural food is the slime or mucus 

 exuded in abundance from the pores, but they fequently retain their hold 

 upon a spot until they have eaten through to the flesh, and deep ulcer- 

 ous cavities occasionally result from the sore. 



The decrease in numbers is. apparent, to a certain extent, in localities 

 where the pound-net has been in use for a number of years. At San- 

 dusky, Ohio, the numbers brought in from the nets and handled at 

 the curing-establishment in a season are said to have- nearly reached 

 eighteen thousand a few years ago, while in 1872 the books showed a 

 record of thirteen thousand eight hundred and eighty received. This 

 fact has several times been advanced as an argument in favor of the 

 pound-net, that the destruction of the sturgeon, asserted to be an ex- 

 tensive spawn-eater, more than compensated for the numbers of white- 

 fish taken. 



25. — An important species. 



There is another species of fish, the wall-eyed pike, Stizostedion 

 americana, a knowledge of whose habits would be important to a proper 

 conservation of the species, but its spawning season is in the spring and 

 earlier than circumstances have permitted us to visit its localities. 



