Translocation of Wild Trochus niloticus: Prospects for Enhancing Depleted Philippine Reefs

Abstract

Intentional release of wild-caught individuals has been widely used to establish new populations of the commercially valuable but threatened reef gastropod Trochus niloticus in oceanic islands. Is this also a viable strategy to enhance depleted populations of this species and other marine invertebrates? We monitored growth and survival of 765 translocated individuals and 486 in their original habitat for 5–9 months. Individuals translocated to a severely overexploited reef (mainland Palawan) grew 2–3 times faster than those at Tubbataha Reefs Natural Park, Phillipines. Despite variations in growth between the three sites, survival probabilities were consistently high, ranging between 0.77 and 0.92. So translocation is feasible, and sites at which a species has previously been found are likely to be suitable for their growth and survival. If site management can control over-fishing, this approach is likely to be a valuable tool for enhancing field populations of a large invertebrates like Trochus that have a short lived planktonic larva.

Keywords:

• growth
• marine protected areas
• reintroduction
• survival rates

ACKNOWLEDGMENTS

We are grateful to the WPU-BMRS personnel, the TRNP Park Rangers and the crew members of the research vessel of the World Wildlife Fund (WWF) for Nature for their assistance during the field activities. The comments from two anonymous reviewers helped improved the manuscript. This study was jointly funded by the Nagao Natural Environment Foundation, Western Philippines University, University of East Anglia, and the Ford Foundation International Fellowship Program.