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 过去数个世纪以来，多塞河（Doce River）经历了剧烈的生态变化，包括流量调控、水体污染、生境破坏及物种丧失。本研究首次对多塞河河口开展了全面的鱼类生物多样性评估，并梳理了18世纪早期以来整条河流所面临的主要干扰及其驱动因素。本次调查共记录鱼类115种，其中鲹形目（Carangiformes）、鲶形目（Siluriformes）及真鲈下组分类位置未定类群（Eupercaria incertae sedis）为优势类群。多数记录物种为本土物种（87.8%）、广盐性/边缘栖息物种（80%）及底栖动物食性物种（33.9%）。受威胁物种包括大眼副颈须鳚（Paragenidens grandoculis）、斑胸海鲇（Genidens barbus）及蓝鳍笛鲷（Lutjanus cyanopterus）；近危物种包括巴西无鳔石首鱼（Cynoscion acoupa）、斑鳞鲈（Dormitator maculatus）、约氏笛鲷（Lutjanus jocu）、西印度笛鲷（Lutjanus synagris）及里氏鲻（Mugil liza），上述近危物种均为边缘栖息类群。另有13个物种为巴西国内或流域尺度下的外来物种：国内外来物种包括暗塘鳢（Butis koilomatodon）、伦氏非鲫（Coptodon rendalli）及尼罗罗非鱼（Oreochromis niloticus）；流域外来物种则包括红腹食人鱼（Pygocentrus nattereri）与黄金河虎（Salminus brasiliensis）。本研究首次在巴西东海岸报道了沙氏海鲶近似种（Cathorops cf. arenatus），同时在多塞河河口发现了曾被认为已在该河流域灭绝的大眼副颈须鳚（Paragenidens grandoculis）。