Intra- and inter-specific variation in buoyancy of some estuarine fishes

Abstract

Buoyancy was measured on eight species of estuarine fishes that were caught in 1 m depth or less. Mean buoyancies of the physoclists Fundulus heteroclitus, F. majalis, Cyprinodon variegatus and Leiostomus xanthurus were similar and ranged from −6.5 to −18.0 kiloPascals below atmospheric pressure at sea level. Menidia menidia and Pomatomus saltatrix measured −36.6 and −46.1 kPa, respectively. Two physostomes, Brevoortia tyrannus and Anchoa mitchilli, measured + 2.9 and −23.5 kPa, respectively, but the latter probably releases air when handled.