Coral reef subsistence fisheries are a pillar of many coastal communities' livelihoods and cultures, and are threatened by climate change and the risk of overexploitation. Despite their importance, these fisheries are often data-deficient, or rarely studied in their socio-economic contexts, making effective management difficult for individual sites.
This study assessed the effects of low levels or subsistence fishing on the relatively pristine coral reef fish community around Aldabra Atoll, a research station in the Seychelles (Western Indian Ocean) using highly resolved fishing and catch data. Over 5 years of continuous monitoring of catch and fishing effort, we found that mean bottom-fishing efficiency (CPUE) declined by 61.7% between 2016 and 2020. Fishing effort (fishing hours) remained stable over time for all fishing zones, but zones closer to the station were visited more frequently. Fish length significantly declined with cumulated fishing effort over time for the 3 most frequently caught families (Emperors, Groupers and Snappers), and fishing depth decreased for those families by 10-20m, associated with smaller individuals being caught. These declines in length and catch depth could be attributed to changes in zoning starting in 2016, causing fishing effort displacement, although the 2015-2016 coral bleaching could have contributed to trends.