Destined to decline? Intrinsic susceptibility of the threatened estuary stingray to anthropogenic impacts
2010
Pierce, Simon J. | Bennett, Michael B.
Evaluating the extinction risk of poorly known fishes is one of the key problems in marine conservation biology. Elasmobranchs are widely recognised to be highly susceptible to anthropogenic impacts, with ecological specialists being particularly at risk. The estuary stingray Dasyatis fluviorum is endemic to near-shore, estuarine and riverine habitats along the eastern coast of Australia. The present study aimed to obtain basic data on the biology and demography of D. fluviorum to inform conservation evaluation of the species. Age and growth data were collected from rays caught in Moreton Bay, Queensland. Maturity occurred at 630mm disc width (WD) (13.4 years) in females and 412mm WD (7.0 years) in males, with maximum age estimates of 21 and 16 years from females and males, respectively. These parameters produced a positive population growth of 1.02year⁻¹ in a stochastic demographic model based on indirect estimates of mortality. The life history parameters of D. fluviorum confer a high to very high vulnerability to population decline, emphasising the need for directed conservation efforts for the species. Without management intervention, even minor levels of additive anthropogenic mortality are likely to lead to the species' conservation status declining further to Endangered based on IUCN classification criteria.
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