Kritzer, Jacob P. (2002) Stock structure, mortality and growth of the decorated goby, Istigobius decoratus (Gobiidae), at Lizard Island, Great Barrier Reef. Environmental Biology of Fishes, 63 (2). pp. 211-216.

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Abstract

Gobiids are an abundant component of coral reef ichthyofauna, yet little is known of their life histories. I examined population structure, mortality and growth of the decorated goby, Istigobius decoratus, a common gobiid of shallow patch reefs on the Great Barrier Reef. Presumed daily increments in sagittal otoliths were used as a proxy for age. The upper age estimate was 266 days suggesting at most an annual life cycle. Instantaneous natural mortality rate estimates were 5.92 year⁻¹ and 7.92 year⁻¹ using two estimators, both corresponding to less than 1% annual survivorship. Specimens ranged from 12 to 84 mm total length. Analysis of size-at-age data indicated linear growth at a rate of 0.33 mm day⁻¹. The linear relationship between size and age meant the population size structure mirrored the age structure with both skewed toward the smallest and youngest classes. High mortality over a 1-year longevity and linear growth suggest high population turnover and, therefore, that I. decoratus and ecologically similar species serve a potentially important role as prey species. This suite of traits is rarely reported for coral reef fishes, which is probably due to the limited attention paid to small-bodied species rather than the rarity of such a life history in these communities.

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