Composition and estimation of shark size on coral reef ecosystem on Dampier Strait MPA, Raja Ampat

Sharks are the top predators in coral reef ecosystems and played a role to maintain ecosystem balance through trophic cascade. Unfortunately, this important role is threatened by their declining population due to the trade of... [ view full abstract ]

Sharks are the top predators in coral reef ecosystems and played a role to maintain ecosystem balance through trophic cascade. Unfortunately, this important role is threatened by their declining population due to the trade of its fins in the international market. In response to this, the Regional Government of Raja Ampat Regency became the first in Indonesia to enforce the protection of shark and manta rays. This provision is implemented through Local Regulation No. 9 / 2012 on Fishing Prohibition on Shark, Manta Rays, and Certain Fish Types in Raja Ampat Sea Waters. The study conducted from 14-22 January 2018 in the Dampier Strait – Raja Ampat found 15 individuals from 3 species of reef shark using an underwater visual census (belt transect and long swim). From 20 dive spots, 8 locations are having sharks; with zonation type compose of 60% in the tourist zone, 33% in the core zone and 7% in open access. The species composition are 73% black tip reef shark (Carcharhinus melanopterus), followed by 20% of the white tip reef shark (Triaenodon obesus), and 7% of the Papuan walking shark (Hemiscylliium frecyneti). The sizes of the sharks found generally are adult (80%), initial phase (7%), and juvenile (13%). The large number of sharks found in mature size and being in protected areas suggests that this location still provides good area for shark regeneration in the future, and low levels of exploitation in the region are a strong signal of successfulness of the ongoing protection.