Abstract
Fish life history is shaped by environmental and ecological circumstances but constrained by phylogeny. Life-history trade-offs can be exposed in a comparison of closely related species with similar niches. We compare the life histories of four closely related and similar-sized, sympatric, omnivorous seabreams (Sparidae) that share the same physical habitat, namely the steentjie Spondyliosoma emarginatum, hottentot Pachymetopon blochii, white stumpnose Rhabdosargus globiceps and Fransmadam Boopsoidea inornata. Samples of each species were obtained in every season from the southwestern Cape, South Africa, to obtain measures of length, mass, gonadosomatic index (GSI) and condition. Large variations in sex ratio, GSI, and spawning season length (SSL) among species are described. Differences in patterns of sex-specific GSI and condition point to different mating systems. Spondyliosoma …