320 Lake Maxinkuckee, Physical and Biological Survey 



fish is not often taken. And the result of my later observations 

 is not favorable to the view that the dogfish is distinctly nocturnal 

 in habit. With a view of determining how active the fish were 

 at night, I have kept them in captivity and I have also watched 

 them at different hours on their spawning grounds, when light was 

 no more than sufficient to enable their outlines to be seen. My con- 

 clusions indicate that the dogfish is rather to be regarded as most 

 active at twilight. It takes the hook best shortly after sundown 

 and during the early morning, and at these times I have seen it ex- 

 ceedingly active under natural conditions. In a general way the 

 fish can hardly be described as shy. As far as taking an alarm is 

 concerned, it behaves very much as a catfish; it is certainly less 

 apt to notice one's approach than, for example, many common 

 teleosts. 



"The general habitat of the fish varies greatly at different sea- 

 sons of the year. In summer it frequents deeper water ; in spring 

 it comes into the marshy shallows and makes its way through reedy 

 places where the water is scarcely deep enough to cover its dorsal 

 fin. In general it affects muddy water. 



"In the matter of feeding, the rapacious nature of the dogfish 

 has already been noted. Its common articles of diet, as Fiilleborn, 

 for example, has noted, are small fishes and crayfish. The latter 

 are especially common in the stomach contents. Among the speci- 

 mens examined by the present writer was noted one, a female, 

 measuring twenty-eight inches, which had eaten among other 

 things, a pickerel twelve inches in length. Another, a female 

 measuring thirty-one inches, contained the columns of eleven fishes, 

 cyprinoids, each about three inches in length. Another, taken at 

 twilight near the margin of a rubbish heap, had eaten scraps of 

 meat and a lump of raw potato, the latter having been taken from 

 the stomach altogether undigested. Among the local fishermen of 

 the Wisconsin lakes, salt pork is well known as a 'killing' bait. I 

 have no evidence that the dogfish eats fish, or more accurately some 

 fishes, after they are dead. Dead perch and sunfish remain un- 

 touched, even in regions where Amia is very abundant. 



"The dogfish deposits its eggs in more or less definitely pre- 

 pared nests.* These often occur very abundantly in the reedy 

 shallow in the margins of the lakes. A particular region of the 

 shore will often be given marked preference : in one case observed 

 by the writer eleven nests occurred within a radius of fifty feet, 

 and seven of these within a radius of fifteen feet. The spawning 



* The writer has obtained good evidence that inconvenient rushes are bitten off when the 

 fish prepares the nest. This is also noted by Reighard. 



