Life history (length-weight relationship, conditional factors, reproductive aspects), stomach contents and nursery ground of stingray in the Arafura Sea

Abstract

Stingrays are a resource that is vulnerable to overfishing and habitat degradation. The research was conducted to obtain data and information that is still lacking and much needed for the utilization and protection of stingrays, including; life history, stomach contents, and nursery ground. The study was conducted in October - November 2018 by exploratory, including taking stingrays by trawling and measuring habitat conditions with Conductivity, Temperature, and Depth. The results showed a total stingrays are 744 individuals, weighing 2,986.6 kg and 24 species. Individual stingrays have a width disc range of 9-134 cm and a weight of 20-67000 g. The growth pattern of stingrays is generally allometric, except for Gymnura zonura. The average value of the relative condition factors is generally >1, except for Aetomylaeus maculatus and Brevitrygon walga. Stingrays have an unbalanced sex ratio, gonads consist of 43% adolescent and 57% mature, and the number of neonates is 1-6 /parent. The correlation between clasper length and disc width is generally positive, except for Hemitrygon longicauda. Of the stomach contents of all stingray species, 64 % is shrimp, Himantura leoparda which have various prey. The area east of Aru and west of Papua are the locations used as nursery grounds by most various stingrays. Nursery grounds of Stingray is generally shallow coastal areas with low oxygen, eutrophic and high turbidity. The results of this study are expected to be used as a basis for managing stingray resources in the Arafura Sea and further research is recommended to be carried out in four different seasons.