266 BULLETIN OF THE BUREAU OF FISHERIES. 



Notropis atherinoides Rafinesque. Shiner. 



Only one shiner was examined for food and it was empty. It was supposed that shiners would be 

 easy to catch alongshore and they were therefore neglected until the period for study was nearly com- 

 pleted — then none was to be found. 



Perca flavescens (Mitchill). Yellow Perch. 



August 15. —NumheT examined, 2; lengths, 68, 73. Food: Chironomus larvse, 10; Orthocaldius 

 larvse, 15; mayfly nymphs, 2.5; caddisfly larvse, 5; Hyalella, 15; ostracods, 0.5; Ceriodaphnia, 52. 



August 18. — Number examined, 5; lengths, 70 to 113, average, 81. Food: Chironomid larvse, 25; 

 mayfly nymphs, 3; chironomid pupae, 34; Hyalella, 12.4; Chydorus sphaericus, 0.2; Eurjxercus, 1.2; 

 Ceriodaphnia, 23.2; sand, i. 



August 32. — Number examined, 2; lengths, 93, 97. Food: Chironomid pupae, 37.5; Hyalella, 

 S9.5; Ceriodaphnia, 0.5; plants, 2.5. 



August 2^. — Number examined, i; length, 74. Food: Chironomid larvae, 22; caddisfly larvae, 2; 

 chironomid pupae, 15; Hyalella, 32.8; Eurycefcus, 23; Ceriodaphnia, 5; sand, 0.2. 



August 2cj. — Number examined, 5; lengths, 115 to 127, average, 122. Food: Chironomid larvae, 5; 

 mayfly nymphs, 4; chironomid pupae, i; mite, 4; crayfish, 16.2; Hyalella, 19; ostracods, +; Physa, 

 39.6; Amnicola, 5; plants, 2.6; Arcellalike seeds, 1.4; algae, 0.2; unknown, 2. 



August 26. — Number examined, i; length, 121. Food: Sialis nymphs, 85; sand, 5; unknown, 10. 



August 28. — Number examined, 4; lengths, 118 to 132, average, 126. Food: Chironomid larvae, 

 19.3; mayfly nymphs, 12.5; caddisfly larvs, 2; chironomid pupae, 2.5; Hyalella, 53.5; Physa, 6.2; 

 plants, 1.2: sand, 0.5; bottom debris, 2; unknown, 0.3. 



August 20  — Number examined, 8; lengths, 72 to 83, average, 77. Food: Chironomid larvae, 9; 

 mayfly nymphs, 14.3; chironomid pupae, 4.4; Hyalella, 49.8; Chydorus, +; Eurycercus, 2.1; Cerio- 

 daphnia, 18. i; plants, 0.6; Arcellalike seeds, 0.6; sand, i.i. 



September I. — Spring Lake Creek; number examined, 7; lengths, 183 to 268, average, 216. Food: 

 Fish, 2.9; chironomid larvae, o. I, • caddisfly larvae, 3.6; dragonfly nymphs, 85.5; Hyalella, i; Physa, 3.3; 

 Sphaeriidae, 1.4; Herbobdella, i.i; plants, 2. 



September 2. — Number examined, i; length, 130. Food: Leptocerus larvae , 5 ; plants, 95. 



September 2- — Trot-line near bar; number examined, 6; lengths, 122 to 143, average, 134. Food: 

 Sialis nymphs, 8; dragonfly nymphs, 10; chironomid pupae, 4; crayfish, 10; Hyalella, 44; Ceriodaphnia, 

 4; oligochaetes, 10; plants, 4; sand, 4; bottom debris, 2. 



Summary. — Number examined, 43; lengths, 73 to 268, average, 112. Food: Fish, 0.5; insect larvae, 

 34.1, insect pupae, 8; mite, 0.5; crayfishes, 3.2; amphipods, 28.2; ostracods, -f; cladocerans, 10.7; 

 snails, 6.6; clams, 0.2; leeches, 0.2; oligochKtes, 1.2; plants, 3.8; sand,i; bottom ddbris, 0.4; unknown, 



°-5- 



The chief foods of the perch are insect larvae, amphipods, and other crustaceans. It is worthy of 

 note that the large perch caught on September i in Spring Lake Creek had eaten 85.5 per cent dragonfly 

 nymphs. The perch's food in all habitats is largely from the bottom and from the aquatic vegetation. 



Pimephales notatus (Rafinesque). Blunt-nosed minnow. 



Three of these little minnows were examined, but only one contained food. This one was caught 

 August 30, measured 52 mm. in length, and had eaten chironomid larvae, 50, and chironomid pupae, 50. 



GENERAL REMARKS ON FOODS. 



Arranged according to their use by all of the 15 species studied in Green Lake, 

 the foods come in the following order: Insect larvae (21.7), amphiphods (16.5), 

 fish (9.6), crayfishes (7.8), cladocerans (7.6), insect pupae (6.7), plants (4.5), snails (4.4), 

 clams (4.1), insects (3.3), ostracods (3.3), sand (2.5), mud (2), oligochaetes (0.6), leeches 

 (0.5), unknown (0.4), mites (0.4), Mysis (0.3), algae (0.2), copepods (o.i). 



Sixty-seven and seven-tenths per cent of the food of the fishes of Green Lake is 

 arthropods; 31.7 per cent, insects in all stages; and 35.6 per cent, crustaceans. About 



