The introduction of non-native predator fish is thought to have important negative effects on native prey populations. Opsanus beta is a non-native toadfish that was originally described in the Gulf of Mexico, between the west coast of Florida and Belize. In the present study, we describe, for the first time, the occurrence of O. beta in Sepetiba Bay (22°55′S), south-eastern Brazil, probably brought into the bay through ships' ballast water. Thirteen specimens were recorded in this area near to Sepetiba Port. Similarly, three other records of this species in the Brazilian coast were also reported near to port areas at Rio de Janeiro (22°49′S), Santos (23°59′S) and Paranaguá (25°33′S) ports. To confirm the species identity, we employed DNA barcoding and compared our samples with sequences deposited on public databases, which indicated that our samples are highly similar (>99.9% of genetic similarity) to O. beta samples collected near its type locality. Several individuals were found in the capable spawning phase, according to histological analysis of the reproductive cell stages. The environmental plasticity of this species and the favourable local environmental conditions probably enabled the establishment of O. beta in this region. This raises concerns of potential high invasion impact due to this species' diet and reproductive capacity.

中文翻译：

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Opsanus beta (Goode & Bean, 1880) (Acanthopterygii: Batrachoididae)，巴西东南部塞佩蒂巴湾的一种非本土蟾鱼

非本地捕食性鱼类的引入被认为对本地猎物种群具有重要的负面影响。Opsanus 测试版是一种非本地蟾鱼，最初在墨西哥湾描述，位于佛罗里达州西海岸和伯利兹之间。在本研究中，我们首次描述了O.贝塔在巴西东南部的塞佩蒂巴湾（22°55′S），可能通过船舶的压载水进入海湾。在塞佩蒂巴港附近的这个地区记录了 13 个标本。同样，在巴西海岸的该物种的其他三个记录也报告了靠近里约热内卢（22°49'S）、桑托斯（23°59'S）和巴拉那瓜（25°33'S）港口的港口区域。为了确认物种身份，我们使用 DNA 条形码并将我们的样本与公共数据库中保存的序列进行比较，这表明我们的样本与O.贝塔在其典型地点附近采集的样本。根据生殖细胞阶段的组织学分析，发现有几个个体处于能够产卵的阶段。该物种的环境可塑性和当地有利的环境条件可能使O.贝塔在这个地区。由于该物种的饮食和生殖能力，这引起了对潜在高入侵影响的担忧。