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. 



^ ujitsi Jj.— Number examined, 2; lengths, 68, 73. Food: Chironomus larvae, 10; Orthocaldius 

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



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

 mayfly nymphs, 3; chironomid pups, 34; Hyalella, 12.4; Chydorus sphaericus, 0.2; Eur>-cercus, 1.2; 

 Ceriodaphnia, 23.2; sand, i. 



August 22. — Number examined, 2; lengths, 93, 97. Food: Chironomid pups, 37.5; Hyalella, 

 59.5; Ceriodaphnia, 0.5; plants, 2.5. 



August 23. — Number examined, i; length, 74. Food: Chironomid larvae, 22; caddisfly larvse, 2; 

 chironomid pupae, 15; Hyalella, 32.8; Eur>-cercus, 23; Ceriodaphnia, 5; sand, 0.2. 



August 2y — 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 sS. — Number examined, 4; lengths, 118 to 132, average, 126. Food: Chironomid larvae, 

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

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



August 30. — 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 larva?, o. I, ■ caddisfly larva?, 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 lar\'a?, 5; plants, 95. 



September J. — 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 larvs, 

 34.1, insect pupae, 8; mite, 0.5; craj'fishes, 3.2; amphipods, 28.2; ostracods, -|- ; cladocerans, 10.7; 

 snails, 6.6; clams, 0.2; leeches, 0.2; oligochaetes, 1.2; plants, 3.8; sand,i; bottomd6bris,o.4; unknown, 



o.S- 



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



