Life-history characteristics of coral reef gobies. I. Growth and life-span

Life-history theory predicts that small species will exhibit short life-spans and fast growth rates; however, previous studies indicate that a positive relationship between size and maximum age may not be universally applicable to coral reef fishes. Here, we investigate the growth and life-span of 5 small species of coral reef goby (family Gobiidae): Istigobius goldmanni, Asterropteryx semipunctatus, Amblygobius bynoensis, Amblygobius phalaena and Valenciennea muralis. All 5 species were relatively short-lived, with the oldest individual sampled ranging from 11 to 16 mo depending on species and sex. Rapid growth occurred over much of the size range of all 5 species and, in contrast to most reef fishes, relatively little or no time was spent at an asymptotic size. Patterns of growth were best described by a Broken Stick model for I. goldmanni, and by either a Broken Stick model or the von Bertalanffy growth function for the other 4 species. Summer-growing individuals had higher growth rates than winter-growing individuals, but this did not affect the overall patterns of growth. Sex-specific differences in growth were evident for I. goldmanni and A. semipunctatus, with males growing faster and attaining a larger maximum size than females. In contrast, there was no significant difference in growth between male and female A. bynoensis, A. phalaena and V. muralis. This pattern may be related to interspecific differences in intensity of sexual selection, mating system, and reproductive behaviour. Overall, the patterns of growth and life-span of these 5 small species conformed to traditional concepts of life-history theory.