26 UNIVERSITY OF WISCONSIN STUDIES 



GENERAL REMARKS ON FOOD 



Table V shows that the foods eaten by the fourteen im- 

 portant species of fishes in Lake Valencia rank as follows, the 

 figures indicating the average percentage by volume for all 

 species: mud 27, snails 12.4, algae 11.8, fish 10.3, plants 6.6, 

 unidentified insect larvae 5.3, chironomid larvae 5.1, may-fly 

 nymphs 4.9, unidentified insects 2.8, caddis-fly larvae 2.4, 

 chironomid pupae 2, ostracods 1.7, unidentified eggs 1.5, 

 sponges 1.4, grasshopper 1.4, Diptera 1.3, sand 1.3, unidentified 

 food 1.2, earthworm 1.1, ants 1, damsel-fly nymphs .7, copepods 

 .6, beetle larvae .5, cladocerans .4, seeds .4, dragon-fly nymphs 

 .3, pebbles .3, Sphaeridae .3, beetles .3, bugs .2, Sialis larvae 

 .1, mites .1, rotifers .1. 



If the foods are collected into larger groups the order is 

 as follows: mud, sand, and pebbles, 28.6; immature insects, 

 19.3; plants, 18.8; molluscs, 12.7; fish, 10.3; adult insects, 7; 

 entomostracans^ 2.7 ; chironomid pupae, 2; unidentified eggs, 

 1.5; sponges, 1.4; unidentified food, 1.2; earthworm, 1.1; mites, 

 .1; rotifers, .1. 



The fishes feeding on particular foods are as follows: 



FISHES: Hoplias malabaricus 90, Aquidens pulcher 16, Cre- 

 nicichla geayi 15, Astyanax bimaculatus 11, Pimelodella 

 metae 8.3, Symbranchus marmoratus 4.5. 



INSECTS AND LARVAE : Symbranchus marmoratus 72.9, Rhamdia 

 quelen 67; Pimelodella metae 62.3, Astyanax metae 45, 

 Gephyrocharax valenciae 35.1, Astyanax bimaculatus 24.2, 

 Aquidens pulcher 23, Lebistes reticulatus 18, Crenicichla 

 geayi 17.7; Creagrutus beni 14, Hoplias malabaricus 8.4. 



ENTOMOSTRACA: Lebistes reticulatus 9.1, Creagrutus beni 7.8, 

 Aquidens pulcher 6, Astyanax bimaculatus .7, Plecostomus 

 plecostomus .5, Curimatus argenteus .1. 



MOLLUSCS: Creagrutus beni 78, Aquidens pulcher 49, Cre- 

 nicichla geayi 47, Rhamdia quelen 3.3, Astyanax bimaculatus 2. 



