Evaluation of fisheries management strategies using a biotic integrity index in floodplain lakes in the lower Solimões River, Amazonas, Brazil

ABSTRACT Fisheries is an important activity in the Amazon basin and potentially has a high impact on ichthyofauna. With the aim of achieving sustainability in fisheries of target species, protected areas were established within a fisheries management framework known as the Amazon Lakes Management System (ALMS). With the aim to evaluate the effect of ALMS on fish assemblages as a whole, we compared floodplain lakes with different levels of fish management in the lower Solimões River, in the Brazilian Amazon, developing an index of biotic integrity, named ALMS-IBI. We sampled fish in three lake categories: protected (PR), managed (MN), and commercially fished (CM). The ALMS-IBI was developed by selecting and testing fish assemblage metrics based on samplings carried out in 2017 and 2018, using gillnets with different mesh sizes. We captured 4565 fish of 113 species and seven trophic categories. The final index is composed of seven metrics related to species richness, trophic structure, and fish abundance, and characterized the fish assemblage in the PR and MN lakes as acceptable, and in the CM lakes as poor. Our results indicate that the ALMS-IBI can be an efficient method to monitor the whole fish assemblage in Amazonian floodplain lakes, and can be used as a complementary tool in the ALMS to assess environmental sustainability.

摘要：渔业是亚马孙流域的重要生产活动，且可能对鱼类区系（ichthyofauna）造成显著影响。为实现目标物种渔业的可持续发展，当地在被称为亚马孙湖泊管理系统（Amazon Lakes Management System, ALMS）的渔业管理框架内设立了保护区。为评估ALMS对整体鱼类群落的影响，研究团队于巴西亚马孙境内的索利蒙伊斯河下游区域，对比了不同鱼类管理等级的泛滥平原湖泊，并构建了名为ALMS-IBI的生物完整性指数（index of biotic integrity）。研究团队对三类湖泊开展鱼类采样：受保护（PR）、管理型（MN）与商业捕捞（CM）湖泊。ALMS-IBI的构建基于2017年与2018年的采样数据，研究人员使用不同网目尺寸的刺网采集样本，筛选并验证了鱼类群落相关指标。本次采样共采集到113种、总计4565尾鱼类，隶属于7个营养类群。最终的ALMS-IBI包含7项与物种丰富度、营养结构及鱼类丰度相关的指标，据此将PR与MN湖泊的鱼类群落评定为可接受状态，CM湖泊的鱼类群落则为较差状态。研究结果表明，ALMS-IBI可作为监测亚马孙泛滥平原湖泊整体鱼类群落的有效手段，同时可作为ALMS框架内评估环境可持续性的辅助工具。