SCALLOPED HAMMERHEAD (Sphyrna lewini) CRITICAL HABITAT IDENTIFICATION TO SUPPORT MARINE PROTECTED AREA DEVELOPMENT IN ACEH JAYA INDONESIA

The scalloped hammerhead shark (Sphyrna lewini) is a top ocean predator, with important ecological and economic values in Indonesia. Their morphology and life-history characteristics make them particularly vulnerable to... [ view full abstract ]

The scalloped hammerhead shark (Sphyrna lewini) is a top ocean predator, with important ecological and economic values in Indonesia. Their morphology and life-history characteristics make them particularly vulnerable to overexploitation, and scalloped hammerheads are now classified as endangered according to the IUCN Red List of threatened species. Hammerheads are one of the most commonly caught shark species groups in Indonesia and in several fisheries in Aceh Province, juvenile scalloped hammerhead sharks are frequently caught as unintentional secondary catch. This study was conducted in Aceh Jaya, Aceh, to provide information on habitat and fisheries characteristics of scalloped hammerhead sharks, as a basis for management and protection. Data was gathered during July-September 2017, and included habitat surveying and landings monitoring. Observers joined fishing vessels to record shark capture locations, while data on landings was also collected from boats in the Rigaih fishing harbour. Our results show that all recorded scalloped hammerhead sharks are juveniles, with average lengths of 63 - 68 cm. The fishing ground where scalloped hammerheads are caught is within 12 miles from the shore of Aceh Jaya. Most of the vessels are small, below 5 GT, and using gillnets as their primary fishing gear to target reef fish, shrimps, and small pelagic fish. The results suggest that the coastal waters of Aceh Jaya are critical habitat for sharks, acting as a nursery ground for scalloped hammerheads. This data is now being used to inform marine spatial planning to improve protection and management of hammerhead sharks in Aceh.