Use of tidal-freshwater and oligohaline wetlands by centrarchid fishes along a coastal river-estuarine gradient is partially controlled by salinity. I examined length-weight relationships between tidal-freshwater and oligohaline populations ofMicropterus salmoides, M. punctulatus, Lepomis microlophus, L. punctatus andL. macrochirus, species that commonly use saline wetlands. Analysis of covariance (ANCOVA) documented significantly heavier specimens ofMicropterus salmoides andLepomis microlophus in tidal-freshwater (P 0.05) in length-weight patterns. Specimens ofL. macrochirus andM. punctulatus were heavier at a given length in tidal-freshwater than oligohaline marshes, but direct comparisons were not possible because of violation of the parallel slope assumption of ANCOVA. Data on some species examined contradict previous laboratory physiological data which suggested that salinity and its rate of change control use of saline habitats by centrarchids. These data support the hypothesis that use of habitat is a multidimension function of abiotic and biotic factors and that laboratory physiological studies based on abiotic factors alone may not provide all the answers to questions centered around life-history consequences of using various habitats.