Fish biodiversity of a tropical estuary under severe anthropic pressure (Doce River, Brazil)

Abstract The Doce River has undergone severe changes over the last centuries (e.g., flow regulation, pollution, habitat and species loss). Here, we present the first comprehensive fish biodiversity assessment of the Doce River estuary and a summary of the main impacts and their drivers for the whole river since the early 18th century. Carangiformes, Siluriformes and Eupercaria incertae sedis were the most representative orders for the 115 species recorded. Most species are native (87.8%), euryhaline/peripheral (80%) and zoobenthivorous (33.9%). Threatened (Paragenidens grandoculis, Genidens barbus, and Lutjanus cyanopterus) and near threatened (Cynoscion acoupa, Dormitator maculatus, Lutjanus jocu, Lutjanus synagris, and Mugil liza) species are peripheral. Thirteen species are exotic at the country (Butis koilomatodon, Coptodon rendalli, and Oreochromis niloticus) or the basin level (e.g., Pygocentrus nattereri and Salminus brasiliensis). The catfish Cathorops cf. arenatus is reported for the first time on the eastern coast of Brazil and Paragenidens grandoculis, considered extinct in the Doce River, was discovered in the estuary.

摘要 多西河（Doce River）在过去数个世纪中经历了剧烈变化，涵盖流量调控、污染、栖息地破坏与物种丧失等方面。本研究首次对多西河河口开展了全面的鱼类生物多样性评估，并总结了18世纪早期以来整条多西河流域面临的主要干扰及其驱动机制。本次共记录115个鱼类物种，其中鲹形目（Carangiformes）、鲇形目（Siluriformes）及真鲈部未定类群（Eupercaria incertae sedis）为优势类群。绝大多数物种为本土物种（占比87.8%）、广盐性/沿岸性物种（占比80%）以及底栖动物食性物种（占比33.9%）。受威胁物种包括大眼副项鲷（Paragenidens grandoculis）、斑海鲶（Genidens barbus）与蓝鳍笛鲷（Lutjanus cyanopterus）；近危物种包括巴西犬牙石首鱼（Cynoscion acoupa）、斑背鲈（Dormitator maculatus）、约氏笛鲷（Lutjanus jocu）、同色笛鲷（Lutjanus synagris）以及利氏鲻（Mugil liza），上述受威胁与近危物种均属于沿岸性类群。另有13个物种在巴西境内或多西河流域范围内为外来物种：巴西境内的外来物种包括暗缟鰕虎鱼（Butis koilomatodon）、伦氏非鲫（Coptodon rendalli）与尼罗罗非鱼（Oreochromis niloticus）；流域范围内的外来物种包括红腹食人鱼（Pygocentrus nattereri）与多拉多鱼（Salminus brasiliensis）等。本研究首次在巴西东海岸记录到砂栖海鲶（Cathorops cf. arenatus）；此前被认为在多西河已灭绝的大眼副项鲷（Paragenidens grandoculis）也在该河口被重新发现。