Behavior Patterns 231 



in summer. The poorest trapping season for crappies in this lake was from 

 about mid-July to late September. Other warm-water fishes also show a 

 tendency to be less active during the hottest part of the summer than in 

 spring and fall. 



Daily Activity. There are many records of daily activity patterns of 

 warm-water fishes. Carlander and Cleary -^ describe three types of diurnal 

 movements of fishes that they observed through the use of gillnets : ( 1 ) 

 more activity at night than in the day time; (2) more activity in daylight 

 than in darkness; (3) activity that resulted in movement from one 

 habitat to another at different periods of the day. These authors listed 

 walleyes and tullibee as being more active at night than in day time, and 

 perch and northern pike as being more active in the day time. They 

 stated tliat common suckers moved into shallow waters at night and into 

 deep water during the day, while carp and yellow bass moved into shallow 

 waters during the day time and into deep water at night. Spoor and 

 Schloemer ^^ had previously reported an inshore and offshore movement 

 of common suckers at Muskellunge Lake, Vilas Covmty, Wisconsin, as- 

 sociated with darkness and daylight (No. 3 above). They could demon- 

 strate no such directional movement in rock bass, but the peaks of 

 activity (catches) for this species were at dusk and dawn, with con- 

 siderable activity during the night. 



Hasler and Bardach ^^ discovered an interesting daily migration of the 

 perch in Lake Mendota (Madison, Wisconsin) beginning about the end 

 of May and continuing into October. These fish moved toward shore in 

 certain areas in the hours before sunset and, to a lesser degree, before 

 sunrise. Once they reached tlie 18-foot (6-meter) contour they changed 

 direction and cruised along parallel to shore. With the coming of dark- 

 ness these fish appeared to disperse rather suddenly. Fish caught at sunset 

 were gorged with freshly ingested water fleas (Daphnia), which sug- 

 gested that this movement may have been a feeding migration. 



The difference in activity periods of closely related species is illustrated 

 by laboratory experiments of Childers -^ using white and black crappies. 

 These two species were placed in separate large aquaria and supplied 

 with a known number of minnows. As the minnows were eaten, they were 

 recorded and others were added to replace them. Both kinds of crappies 

 consumed more minnows during the 2-hour dusk period than they did 

 during the 2-hour dawn period and more food was consumed at night 

 than during the day, but while the black crappies ate 2.5 per cent of their 

 food during dayhght hours, the white crappies consumed 14.8 per cent 

 of their food in daylight. A similar difference in feeding habits of the two 

 kinds of crappies is suggested by a trapping study conducted by David 

 H. Thompson ^^ in which 31 per cent of the white crappies netted in 



