Elasmobranchs from Indonesian Waters: Feeding Ecology and Trypanorhynch Cestode Fauna Composition to Support Efforts in Shark and Ray Conservation

Abstract

Purpose: The stomachs and spiral valves of sharks and rays were examined for their trypanorhynch (Cestoda) parasite fauna and dietary items to infer feeding ecology. In Indonesia, sharks and rays have been experiencing increasing awareness and conservation in the recent years due to high fisheries activities and to avoid future species extinction. Methods: The samples were collected in 2009 from two different sampling sites at the southern coasts of Java and Bali in Indonesia. The parasite fauna was studied for 41 elasmobranch fishes. Amongst these, three shark species, Carcharhinus sorrah, Carcharhinus sp. I and Squalus megalops and seven ray species, Brevitrygon heterura, B. cf. heterura, Gymnura zonura, Maculabatis gerrardi, Mobula kuhlii, Neotrygon cauruleopuncatata and Rhinobatos penggali were studied. Four additional specimens, belonging to the shark species Carcharhinus sp. II and Mustelus cf. manazo and the ray species Maculabatis gerrardi were studied from the waters of South Bali. Results: Analyses of the feeding ecology of the ray M. gerrardi revealed distinct differences between both sampling sites, indicating the presence of ecological differences between the geographically independent regions. A total of 11 different trypanorhynch species/taxa belonging to the five families Eutetrarhynchidae (5), Gilquiniidae (1), Lacistorhynchidae (1), Pterobothriidae (1) and Tentaculariidae (3) were found. Ten trypanorhynch species from Penyu Bay and four species from South Bali could be identified. Two taxa that might represent new species were collected: Dollfusiella sp. from Brevitrygon heterura and Prochristianella sp. from Maculabatis gerrardi. Conclusions: The present paper gives insights in using the trypanorhynch cestode community in combination with feeding ecology analyses to support conservation of elasmobranchs in Indonesian waters.