PEARSE FISHES OF LAKE VALENCIA, VENEZUELA 19 



mid pupae + ; fly .9; ostracods 5.8; snails 49; plants 2.5; 

 bottom mud 3. 



The chusco feeds on muddy bottoms upon the most abun- 

 dant foods snails constituting the chief item in its dietary. 



Astyanax bimaculatus (Linnaeaus), Sardina 



This large sardina was found in all parts of the lake, but 

 was most abundant near the islands. 



Isla del Euro, 2 m., July 9; number examined, 1; length 95. 

 Food: midge pupae 30; cladocerans 30; plants 20; plankton 

 algae 20. 



Isla del Euro, 11 m.; July 10; no. ex., 3; lengths: 120, 105, 

 109, ave. 108. Food: fish 33.3; midge pupae 12; plants 8; 

 plankton algae 46.7. 



Isla del Euro, 7 m., July 10; no. ex., 3; lengths 106, 92, 89, 

 ave. 96. Food: fish 15; Sialis nymph 3; insects 13; snail eggs 

 1; plants 20; Wolffia 7; algae 10. 



Isla del Euro, 11 m., July 10; no. ex., 1; length 96. Food: 

 fish 35; fly 25; plants 35. 



Isla del Euro, 1.5 m., July 10; no. ex. 2; length 96, 90. Food: 

 plants 40; plankton algae 60. 



Mouth of Rio Bue, July 19, no. ex., 2; lengths 28, 32. Food: 

 insect remains 100. 



Mouth of Rio Bue, July 20; no. ex., 2; length 78, 85. Food: 

 unknown 50; insects 35; algae 15. 



Off rush-grown shore, 12 m., July 28; no. ex., 3, length 95. 

 Food (2 empty): insect nymph 2; plants 60, algae 38. 



This is the largest "sardina" found in Lake Valencia and 

 more than half of its food consists of vegetation, including 

 plankton. It therefore goes back to the fundamental sources 

 of food in the lake for its energy and in turn serves as food for 

 caimans, cormorants, herons, and predacious fishes. 



Astyanax metae Eigenmann, Sardina 



Rio Castano, July 27; number examined, 4; length 116-79, 

 ave. 97. Food: may fly nymphs 45; plant remains 49; seeds 6. 



These four specimens were examined in order to compare 

 another species in the same genus with the last. Although 

 this species was confined to rivers, its food was much the same 

 as that of its relative in the lake more than half vegetation. 



