Growth, mortality and turnover rates of a small detritivorous fish

Abstract

Growth, mortality and density estimates of the blenny Salarias patzneri were used to quantify turnover rates of a small-bodied detritivorous fish. Turnover rates of S. patzneri were then compared with prominent scarids and acanthurids, to assess the relative significance of small detritivores to secondary production on coral reefs. Instantaneous mortality, estimated from growth parameters (L∞ = 5.10, K = 3.25, t0 = 0.10), suggests that less than 99% of the S. patzneri population survives for more than 1 yr. Despite their small body size, high mortality rates combined with high densities give S. patzneri high annual biomass turnover rates that are similar to larger-bodied acanthurids and scarids. Dietary analysis determined that all post-settlement S. patzneri, from juveniles to the largest adults, are detritivorous. The high turnover rates and diet of S. patzneri emphasize the importance of small-bodied fish and detritus to coral reef trophodynamics.