Programa de Pós-Graduação em Sistemas Aquáticos Tropicais, Universidade Estadual de Santa Cruz, - Rod. Jorge Amado, km 16 - Salobrinho, Ilhéus, BA. CEP: 45662-900, Brazil; Centro de Formação em Ciências Ambientais, Universidade Federal do Sul da Bahia, Campus Sosígenes Costa, BR 367, km 10, Rodovia Porto Seguro-Eunápolis, CEP: 45810-000, Porto Seguro, BA, Brazil.
Laboratório de Fitopatologia Molecular, FITOMOL/CEPEC/CEPLAC, Km 22 Rodovia Ilhéus/Itabuna, Ilhéus, BA, Brazil.
Mar Environ Res. 2018 Nov;142:155-162. doi: 10.1016/j.marenvres.2018.10.004. Epub 2018 Oct 9.
The greenback parrotfish, Scarus trispinosus, is the largest herbivorous fish inhabiting Southwestern Atlantic reefs, and was recently included in the IUCN red list of threatened species as endangered due to the overexploitation of their populations. The aim of this work was to evaluate the existence of structured populations (i.e. genetic unities) along a coast of approximately 2000 km of the NE Brazilian coast. The transferability of 17 primers synthesized for Scarus rubroviolaceus was tested for S. trispinosus and five transferable loci were validated and used. Two localities within the Abrolhos Bank, off the Central Brazilian coast (Corumbau and Caravelas) and in close proximity to the MPA, which encompasses the largest remnants of the S. trispinosus population, exhibited higher levels of genetic richness. Remaining locations, Pernambuco, Porto Seguro and Rio Grande do Norte exhibited lower genetic diversity. We found no genetic differences among sampled localities however, when those samples were gathered into latitudinal groups (northern vs southern) a subtle but significant genetic substructuring was revealed. It is proposed that a combination of high local individual admixture favoured by habitat connectivity drived genetic homogeneity at regional scales while larval dispersal contributed to heterogeneities observed at large scales maintaining gene flow through oceanographic currents.
绿颊鹦嘴鱼，即 Scarus trispinosus，是栖息在西南大西洋珊瑚礁中的最大草食性鱼类，由于其种群过度捕捞，最近被列入 IUCN 濒危物种红色名录。本研究旨在评估巴西东北部约 2000 公里海岸线上存在结构种群（即遗传单元）的情况。为 Scarus rubroviolaceus 合成的 17 对引物的可转移性已针对 S. trispinosus 进行了测试，验证并使用了其中 5 个可转移的基因座。在巴西中部沿海的 Abrolhos 暗礁（Corumbau 和 Caravelas）和紧邻海洋保护区的两个地点，遗传丰富度较高。在距离 Abrolhos 暗礁不远的 Pernambuco、Porto Seguro 和 Rio Grande do Norte 等其他地点，遗传多样性较低。尽管我们没有发现采样地点之间存在遗传差异，但当将这些样本按纬度分组（北部和南部）时，发现存在细微但显著的遗传亚结构。这表明，由生境连通性驱动的高局部个体混合，有助于在区域尺度上保持遗传同质性，而幼虫扩散则有助于在大尺度上保持遗传异质性，从而通过海洋洋流维持基因流。
