Stock assessment of trochus (Trochus niloticus) (Gastropoda. Trochidae) fisheries at West Nggela, Solomon Islands

Abstract

Stock abundance estimates of trochus at four sites at West Nggela were obtained using the Peterson mark-recapture technique. Densities were calculated using reef areas obtained from high resolution aerial photographs. Densities on most reefs were apparently low compared to well-managed trochus fisheries elsewhere in the Pacific. A further six reefs did not have sufficient numbers of trochus for an estimate to be made using mark-recapture. Egg-per-recruit (EPR) and yield-per-recruit (YPR) analyses were performed using total mortality (Z) estimates derived from size-frequency data from harvests at a number of sites, and two growth rates drawn from previous studies on the Great Barrier Reef. Na..