Premium
Selective Predation with Respect to Body Size in a Population of the Fish Xenomelaniris Venezuelae (Atherinidae)
Author(s) -
Unger Philip A.,
Lewis William M.
Publication year - 1983
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1937824
Subject(s) - predation , biology , rotifer , fish <actinopterygii> , population , fishery , population dynamics of fisheries , zoology , ecology , demography , sociology
The food habits of the planktivorous fish Xeonomelaniris venezuelae (Atherinidae) in Lake Valencia, Venezuela, were studied in relation to fish size. Mean selection for major prey types and mean breadth of diet were determined for each size class of fish. The smallest fish select the rotifer Brachionus calyciflorus while successively larger fish select successively larger prey. Mean length and mean dry mass of the items eaten by the fish are directly related to fish length. Diet breadth, however, is inversely related to fish length, indicating that large fish feed more selectively than small fish. Evidence is presented which suggests that the relationship between Xenomerlaniris body size and prey selection is due to increased capture efficiency with size, and that the relationship of body size to diet breadth results from growth—related improvements in vision.