Mortality and exploitation of marbled spinefoot, Siganus rivulatus (Actinopterygii: Perciformes: Siganidae), from southern Aegean Sea small-scale fishery

Abstract

Background. In the small-scale fisheries of the Gulf of Gökova (Turkish coast of the southern Aegean Sea) the marbled spinefoot, Siganus rivulatus Forsskål et Niebuhr, 1775, is a commercially important species. No sustainability study, however, has been carried out on the stock assessment and management of this species in the gulf. The aim of the presently reported study was to determine the mortality and biological reference points of Siganus rivulatus and suggest a proper fishery management plan for fishery regulations. Materials and methods. The sudy was conducted between July 2016 and June 2018. Fish samples were collected from the Gulf of Gökova small-scale fishery. The total mortality (Z), natural mortality (M), fishing mortality (Fcurr), and exploitation rate (Ecurr) were determined and compared with the biological reference points: the optimum fishing mortality (Fopt), fishing mortality limit reference point (Flim), optimum exploitation rate (Eopt). Results. Total mortality (Z), natural mortality (M), fishing mortality (Fcurr), and exploitation rate (Ecurr) were found to be 0.67, 0.32, 0.35, and 0.52, respectively. Furthermore, biological reference points (Fopt, Flim, Eopt) attained values of 0.16, 0.21, and 0.33 cm, respectively. Conclusion. The fishing pressure for Siganus rivulatus stocks the Gulf of Gökova should decrease for the sake of the sustainability of this resource.