Analysis of the supply chain and conservation status of sharks (Elasmobranchii: Superorder Selachimorpha) based on fisher knowledge

Increasing fishing effort has caused declines in shark populations worldwide. Understanding biological and ecological characteristics of sharks is essential to effectively implement management measures, but to fully understand drivers of fishing pressure social factors must be considered through multidisciplinary and integrated approaches. The present study aimed to use fisher and trader knowledge to describe the shark catch and product supply chain in Northeastern Brazil, and evaluate perceptions regarding the regional conservation status of shark species. Non-systematic observations and structured individual interviews were conducted with experienced fishers and traders. The demand and economic value of shark fins has reportedly decreased over the last 10 years while the shark meat trade has increased slightly, including a small increase in the average price per kilogram of meat. Several threatened shark species were reportedly often captured off shore and traded at local markets. This reported and observed harvest breaches current Brazilian environmental laws. Fishing communities are aware of population declines of several shark species, but rarely take action to avoid capture of sharks. The continuing capture of sharks is mainly due to a lack of knowledge of environmental laws, lack of enforcement by responsible authorities, and difficulties encountered by fishers in finding alternative income streams. National and regional conservation measures are immediately required to reduce overfishing on shark populations in Northeastern Brazil. Social and economic improvements for poor fishing communities must also be implemented to achieve sustainable fisheries.全球捕捞强度的持续攀升已导致世界各地鲨鱼种群数量下降。若要有效落实鲨鱼保护管理措施，明晰其生物学与生态学特征是必要前提；但要全面洞悉捕捞压力的驱动因素，则需通过多学科融合的整合性研究方法纳入社会因素考量。 本研究旨在借助渔民与商贩的经验知识，刻画巴西东北部海域的鲨鱼捕捞及产品供应链，并评估当地对鲨鱼物种区域保护现状的认知。研究团队针对经验丰富的渔民与商贩开展了非系统性观测与结构化个人访谈。 据调研记录，过去十年间鱼翅的市场需求与经济价值有所下滑，而鲨鱼肉贸易则小幅增长，其每公斤平均售价亦出现小幅提升。据悉，多种受威胁鲨鱼物种常在近海被捕获，并在当地市场流通售卖。本次调研记录与观测到的捕捞行为，已违反巴西现行环境法律法规。 捕捞社区虽已意识到部分鲨鱼种群数量下降，但极少采取措施避免捕捞鲨鱼。持续捕捞鲨鱼的主要成因包括：渔民对环境法律法规认知不足、相关执法部门监管缺位，以及渔民难以找到替代收入来源。 亟需出台国家级与区域级保护措施，以缓解巴西东北部海域鲨鱼种群面临的过度捕捞压力。同时，还需改善贫困捕捞社区的社会与经济状况，以实现渔业可持续发展。