4 NORTHERN FISHES 



bite readily on certain live aquatic insect larvae, which are now used 

 successfully as bait for winter angling. Minnesota bluegills when kept 

 in aquaria feed very little in winter. 



Northern fishermen have long complained about the poor fishing in 

 August and the last part of July. Creel censuses of northern lakes show 

 that fishes do not bite as well most days during the late summer as 

 they do during the early summer. Several factors may be responsible 

 for this. This season is the period of greatest food production in north- 

 ern waters and consequently fishes may be well fed and not hungry. 

 Also the water reaches its highest temperature during the last of July 

 and the first part of August, and many fishes may seek the cooler 

 and deeper waters. There is a further possibility that some fishes may 

 not feed much when the water temperature is above their optimum, 

 just as many fishes feed little or not at all when temperatures are ex- 

 tremely low. 



How fishes detect their food — whether by sight, taste, or smell — 

 is a controversial question. In some species the sense of taste must be 

 poor, for otherwise they would not eat such unpalatable objects as 

 pieces of wood and bits of corncob. Undoubtedly many game fishes 

 are attracted to their food by sight, but since they are rather near- 

 sighted they apparently detect their food by the movement of the 

 object rather than by recognizing its detailed appearance. Bass and 

 northern pike, even those kept in captivity, do not feed readily on 

 nonliving food. 



The best results in feeding dead animals to bass are generally ob- 

 tained by moving the food over the surface of the water. The bass 

 usually take it readily under these conditions. One smallmouth bass 

 kept for some years was first fed on live mice from the janitor's traps. 

 Dead mice held no attraction until it was discovered that if the mice 

 were pulled by the tail over the surface of the water the bass would 

 take them readily. It was also discovered that the bass would strike 

 at a finger moved through the water. 



Different fishes attack their food differently. Bass, walleyes, and 

 dogfish spot their prey, turn and eye it momentarily, and then seize 

 it. Sometimes they will mouth it for a second before swallowing it. 

 Northern pike and muskellunge will poise aimed at a minnow. As long 

 as the minnow is stationary they do not strike, but when the minnow 

 moves they strike it almost faster than the eye can follow. Gars slide 

 smoothly alongside of their prey, dead or alive, and with an easy and 

 graceful sideswipe seize it in their long jaws, completely severing a 

 large fish into halves. Most game fishes swallow their food head first. 

 Their prey may be seized by the tail but it is usually shifted into 

 proper position before being swallowed. 



Because of this propensity of many game fishes to strike moving 

 objects, the fisherman can fool them with artificial minnows, plugs, and 



