Abstract

The objective of this study was to conduct a preliminary investigation of the interplay between reproductive behavior and spawning strategy in territorial (E. morio, E. guttatus, and M. microlepis) and non-territorial (E. striatus) grouper species. Non-territorial males tend to have high gonadosomatic index (GSI) and are sperm competitors, while territorial males tend to have low GSI's and are resource (mate) competitors. Epinephelus striatus has a substantially higher GSI than the other three species, indicating its strategy as a sperm competitor. The physiology/anatomy/behavior relationship has been shown elsewhere between males within a species, but has not before been described across related species in which each species exhibits only one reproductive type. This relationship becomes important when we consider decreased overall male densities and associated skews of sex ratio in some groupers. This may lead to a disruption of the positive feedback loops and a physiological explanation for depensation/Allee affects in certain grouper species

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