SREL Reprint #1776
Growth and mortality of juvenile sunfishes (Lepomis sp.) under heavy predation
M. C. Belk
Savannah River Ecology Laboratory, Aiken, South Carolina, USA
Department of Zoology, University of Georgia, Athens, USA
Abstract: The relationship among growth, energy storage and mortality of juvenile bluegills (Lepomis macrochirus, Rafinesque) experiencing heavy predation was experimentally investigated in a large reservoir where piscivorous largemouth bass (Micropterus salmoides, Lacépède) were abundant. I conducted experiments evaluating interspecific competition, density-dependent growth and lipid content and habitat-specific growth and mortality rates of juvenile bluegills in this reservoir. Enclosure experiments showed that the growth rates of bluegills were unaffected by presence of other Lepomis species but decreased with increasing bluegill density. However, at densities corresponding to those found in the reservoir, the growth rates of bluegills were high, and competition appeared to be relatively unimportant. The percentage lipid content of bluegills was unaffected by the presence of other species, density of bluegills or habitat. The growth rates of bluegills in vegetated refuge areas were significantly higher and mortality rates were significantly lower compared with open water habitats. The low densities and high growth rates of juvenile bluegills in refuge environments suggests that there is a strong lethal effect of predators on this population of bluegills.
Keywords: competition; predation; growth; mortality; lipid level; refuging prey; bluegill; Lepomis macrochirus
SREL Reprint #1776
Belk, M. C. 1993. Growth and mortality of juvenile sunfishes (Lepomis sp.) under heavy predation. Ecology of Freshwater Fish 2: 91-98.
This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).