Stock structure of the goldband snapper Pristipomoides multidens (Pisces:Lutjanidae) from the waters of northern and western Australia by stable isotope ratio analysis of sagittal otolith carbonate

Abstract

Measurement of stable isotope ratios ( 18 O/ 16 O and 13 C/ 12 C) in the sagittal otolith carbonate from assemblages of goldband snapper Pristipomoides multidens from waters off northern and western Australia revealed location-specific signatures and indicated that fish from all sites sampled within Australia (Exmouth, Rankin Bank, Broome, Vulcan Shoals, Timor Sea, Arafura Sea), Indonesia (Kupang) and Papua New Guinea (Pommern Bay) were different. The significant differences in the isotopic signatures of P. multidens demonstrated that there is unlikely to be substantial movement of fish among these distinct adult assemblages. The stable isotopic signatures for the fish from the different locations were persistent through time, and therefore it could be concluded that the fish comprise separate stocks for many of the purposes of fisheries management. The ratios of the stable oxygen isotopes in P. multidens were significantly related to sea surface temperatures (r 2 = 0.797). This study has provided further evidence that measurement of the stable isotope ratios in teleost sagittal otolith carbonate can be a valuable tool in the delineation of fishable stocks or fishery management units of adult fish where the range of distribution of the species in question covers waters with different temperature regimes.