Impact Assessment of Topshell Trochus niloticus Stock Enhancement in Honda Bay, Palawan

Abstract

The impact of the topshell Trochus niloticus stock enhancement in Honda Bay, Palawan was assessed using biological and sociological data. Results indicate that topshells in the protected area are significantly bigger in mean size compared to that in the unprotected area. The abundance in terms of number of individuals per hectare or the density of topshells in the protected area having 70.00 individuals per hectare is significantly higher compared to that in the unprotected area with only 27.50 individuals per hectare. It was found out that the density of topshells in the protected area increased significantly through time. Statistical analysis also showed that the sizes of the topshell in deep water station had significantly increased after more than two years of restocking. At the deep-water station, present study estimated the density of topshell in protected area at 190.00 individuals per hectare, all consisting of mature (26 cm) individuals.

Results of the present study further indicate that topshell as a resource is obviously heavily overexploited. The absence of mature topshells in the deeper waters of the unprotected area, including the area just outside of the sanctuary, indicates the magnitude of harvesting of the resource.

The data presented above validated the perceptions of the community that the restocking initiative in combination with protection, generally resulted into positive effects to their livelihood.