Fisheries and Biological Aspects of Dusky Shark Carcharhinus obscurus (Lesueur, 1818) in Muncar Fishing Port, Banyuwangi, Indonesia

Abstract

The high of catching intensity or overfishing of dusky whaler shark, Carcharhinus obscurus (Lesueur, 1818), has threatened its sustainability. Even though fisheries and biological aspects of C. obscurus are important as a basic assessment for making regulation of shark fisheries management. However, those studies never been reported in Indonesia. The aim of this study is to identify the number of catches and biological aspects of C. obscurus. This study was conducted from January to March 2018 at Fishery Port Technical Implementation Unit (FP-TIU) Muncar, Banyuwangi, Indonesia. 54 C. obscurus individuals were obtained using random sampling survey method. Here, we found that the number of C. obscurus landed in 2018 was higher compared to 2014 and 2017. The shark length ranged from 172 to 394 cm. Percentages of male and female adults of C. obscurus were 22.22 and 46.30%, respectively. Whilst in the juveniles were 20.37% males and 11.11% females. The maturity rate based on clasper length, male landed sharks was 82.61% classified within full calcification and 17.39% non-full calcification level. The sex ratio of C. obscurus sharks that are landed was 1:1.34 (M: F).