Monitoring landed seahorse catch in a changing policy environment

摘要

For many small-scale, tropical reef fisheries, landed catch may be the only data that can be monitored to assess the impacts of management. This is true for seahorses Hippocampus comes that are obtained as part of a multi-species fishery in the Philippines. Here, because seahorses are locally rare and depleted, it is difficult to attain large enough sample sizes to detect changes over time using underwater surveys. We assessed changes in seahorse sales at 2 sites, from 1996 and 2005 respectively to 2010. The study period covered local and national conservation initiatives that could affect seahorses and dependent fisheries: establishment of marine reserves (1998 onwards), a community-led minimum size limit (MSL: 2002 to 2004) and a national ban on seahorse fishing (from 2004). The MSL appeared to lead to increased sizes of seahorses in trade, as hoped, while the national ban led, perversely, to more fishers selling seahorses. Declines in overall take after 2004 or 2007 (depending on the site) is likely linked to declining seahorse populations rather than reduced effort, especially when one considers the increased number of fishers and the price per seahorse. It is notable that communities decided on the MSL, whereas the government imposed the ban on capturing seahorses. In this small-scale, multi-species fishery, monitoring a wide range of variables intensively over a relatively long time scale allowed us to identify key differences between small-scale and industrial fisheries management, and also to document the biological and social consequences of management action for a depleted, threatened species.