Freshwater fishes of the Bahia State, Northeastern Brazil

Abstract: This work was carried out from the assessment of the conservation status of the freshwater ichthyofauna from Bahia State. The inventory data and species distribution were obtained from the specialized scientific literature and representative ichthyological collections. A total of 281 native species was recorded in Bahia State, distributed in the Northeastern Mata Atlantica (NMA) and São Francisco (SFR) freshwater ecoregions. There was a larger number of species in the NMA (187 spp.), composed by several coastal basins, than in the SFR (134 spp.), composed by São Francisco river basin. Among the 30 families recorded, Characidae and Rivulidae were the most representative, with 53 and 48 species, respectively. The conservation status of 214 species was assessed and 33 of them (15%) were included in the IUCN threat categories. Of these, 11 species were classified as vulnerable (VU), 12 as endangered (EN), and 10 as critically endangered (CR). Most threatened species (n = 14) belongs to the family Rivulidae. The larger number of threatened species in the NMA: (n = 23) is mainly related to the high endemism of restricted-range species associated with the human occupation impacts along the coastal regions. In the SFR, most of threatened species are annual killifishes, which are locally disappearing due to increasing degradation of their temporary habitats.摘要：本研究针对巴伊亚州淡水鱼类区系的保护现状开展评估。研究所需的编目数据与物种分布信息均取自专业学术文献及代表性鱼类馆藏标本。巴伊亚州共计记录到281种本土鱼类，其分布覆盖东北大西洋沿岸森林淡水生态区（Northeastern Mata Atlantica, NMA）与圣弗朗西斯科淡水生态区（São Francisco, SFR）。其中东北大西洋沿岸森林淡水生态区包含187种，由多个沿海流域构成，物种数量多于以圣弗朗西斯科河流域为主体的圣弗朗西斯科淡水生态区（134种）。在本次记录的30个鱼类科中，脂鲤科（Characidae）与假鳃鳉科（Rivulidae）为最具代表性的类群，分别包含53种与48种。研究对其中214种鱼类的保护现状进行了评估，其中33种（占比15%）被纳入国际自然保护联盟（IUCN）的受威胁等级范畴。在这33种受威胁物种中，11种被列为易危（VU）、12种为濒危（EN），另有10种为极危（CR）。受威胁物种中数量最多的类群为假鳃鳉科，共计14种。东北大西洋沿岸森林淡水生态区的受威胁物种多达23种，该现象主要与该区域内分布范围受限的特有物种占比偏高，且沿海区域受人类活动干扰强烈密切相关。而在圣弗朗西斯科淡水生态区，受威胁物种多为一年生鳉类，由于其临时栖息环境持续退化，这类物种正面临局部灭绝的风险。