Assessing the small-scale shark fishery of Madagascar through community-based monitoring and knowledge

摘要

Over 90 of those employed in commercial capture fisheries work in the small-scale fisheries (SSF) sector and an estimated 97 of small scale fishers are found in least developed countries. However, the capacity for monitoring SSF globally is low and there is a paucity of data, in particular for remote areas within developing nations. The methods presented here demonstrate a low cost participatory approach for gathering data on small-scale fisheries, in particular for those that take place across remote areas. Community-based data collectors were trained to record biological and socioeconomic data on the traditional (non-motorised) shark fishery in the Toliara region of Madagascar over a six year period (2007-2012). An estimated 20 species of shark were recorded, of which 31 (n = 3505) were Sphyrna lewini (scalloped hammerhead), a species listed by the IUCN as Endangered (IUCN, 2016). Although the number of sharks landed annually has not decreased during our survey period, there was a significant decrease in the average size of sharks caught. Despite multiple anecdotal reports of shark population declines, interviews and focus groups highlight the possibility that shark landings appear to have been maintained through changes in gear and increases in effort (eg. number of fishers, time spent fishing), which may mask a decline in shark populations. The numbers of sharks taken by the traditional fishery in our study region was estimated to be between 65,000 and 104,000 year(-1), whilst estimates using national export and import of dried shark fin from Madagascar, and shark length data in this study, put total landings between 78,000 and 471,851 year(-1). Reliable data on the total volume of sharks landed in Madagascar's waters is scarce, in particular from foreign industrial boats both directly targeting shark species and as bycatch in fisheries targeting other species. There is currently no legislation in place to protect sharks from overexploitation in Madagascar and an urgent need to address the lack of shark fishery management across the traditional, artisanal and industrial fisheries. (C) 2016 Elsevier B.V. All rights reserved.