An overview of the estuarine ichthyofauna from Bahia, Brazil: expanding the knowledge about the fish species of three important regions of the state

The coast of Bahia state is the longest along the Brazilian coastline, and there are significant knowledge gaps concerning its estuarine fish fauna. Thus, there is a need to provide extensive coverage of the estuarine ichthyofauna of Bahia to provide an updated checklist of its fishes, which could function as a database for the management of such biodiversity. Therefore, this study aimed to characterize three different important estuarine systems (Camamu, Todos os Santos Bay, and Caravelas) in Bahia to contribute information on the ichthyofauna in shallow areas of the state. We recorded 29 orders, 54 families, 101 genera, and 147 species of fish. The families with the highest number of species were Sciaenidae and Carangidae, with twelve and nine species, respectively, followed by Gobiidae and Engraulidae, each with eight species. In terms of abundance in the northern region, the orders Atheriniformes (28.80%), Pleuronectiformes (15.92%), Clupeiformes (14.20%), and Gerreiformes (13.91%) predominated. In the Central region, Gerreiformes (21.55%), Tetraodontiformes (17.94%), Gobiiformes (12.83%), and Clupeiformes (8.94%) were the most representative. In the southern region, the orders Clupeiformes (57.48%), Mugiliformes (14.09%), Atheriniformes (4.10%), Lutjaniformes (3.97%), Gerreiformes (3.60%), and Carangiformes (2.23%) predominated. The region was characterized by a high representation of guilds of marine migrant species, followed by marine, estuarine, and freshwater visitors.巴伊亚州沿岸是巴西境内最长的海岸线区段，目前针对该区域河口鱼类区系的相关研究仍存在显著的认知空白。因此，亟需对巴伊亚州的河口鱼类区系开展全面调研，以编制该区域鱼类的更新版名录，该名录可作为此类生物多样性管理的数据库支撑。为此，本研究以巴伊亚州三处重要的河口系统——卡马穆河口、多斯桑托斯湾以及卡拉韦拉斯河口为研究对象，旨在明确该州浅水区的鱼类区系特征，为相关研究提供基础数据。本次调研共记录到鱼类29目、54科、101属、147种。物种丰富度最高的类群为石首鱼科（Sciaenidae）和鲹科（Carangidae），分别包含12种和9种；其次为鰕虎鱼科（Gobiidae）和鳀科（Engraulidae），各包含8个物种。就北部区域的物种丰度而言，占比最高的类群依次为银汉鱼目（Atheriniformes，28.80%）、鲽形目（Pleuronectiformes，15.92%）、鲱形目（Clupeiformes，14.20%）以及银鲈目（Gerreiformes，13.91%）。中部区域的优势类群则为银鲈目（21.55%）、鲀形目（Tetraodontiformes，17.94%）、鰕虎鱼目（Gobiiformes，12.83%）以及鲱形目（8.94%）。南部区域占主导的类群依次为鲱形目（57.48%）、鲻形目（Mugiliformes，14.09%）、银汉鱼目（4.10%）、笛鲷目（Lutjaniformes，3.97%）、银鲈目（3.60%）以及鲹形目（Carangiformes，2.23%）。该区域的鱼类区系以海洋洄游物种类群占比最高，其次依次为海洋物种、河口物种以及淡水到访物种。