Anderson A B, Salas E M, Rocha L A, Floeter S R
Marine Macroecology and Biogeography Lab, Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, SC, 88010-970, Brazil.
Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, CA, 95060, U.S.A.
J Fish Biol. 2017 Aug;91(2):558-573. doi: 10.1111/jfb.13363. Epub 2017 Jul 13.
The damselfish Chromis limbata is native to the Macaronesian Archipelagos (Azores, Madeira and Canaries) and the western coast of Africa between Senegal and Angola. During the austral summers of 2008 and 2009 the species was recorded for the first time in the south-western Atlantic Ocean around Campeche and Xavier Islands, in Florianópolis, Santa Catarina State, Brazil. Here, the progression of C. limbata in southern Brazilian waters is described using visual counts and genetic surveys and changes in the density of the native congener Chromis multilineata were also investigated. Underwater visual censuses of both Chromis species were carried out from 2009 to 2014. Chromis limbata tissue samples were collected and the mtDNA control region was sequenced and compared with mtDNA haplotypes from the natural range to confirm species identity, compare genetic diversity and to infer connectivity between newly established Brazilian populations. The Brazilian population of C. limbata increased significantly over the past 5 years and the effect on C. multilineata is still an open question, longer time-series data will be necessary to clarify possible interactions. The molecular analyses confirmed species identity, revealed strong haplotype connectivity among Brazilian study sites and showed a low genetic diversity in Brazil when compared with the native populations, suggesting few individuals started the invasion. Four hypotheses could explain this colonizing event: C. limbata was released by aquarium fish keepers; larvae or juveniles were transported via ship ballast water; the species has rafted alongside oil rigs; they crossed the Atlantic Ocean through normal larval dispersal or naturally rafting alongside drifting objects. The rafting hypotheses are favoured, but all four possibilities are plausible and could have happened in combination.
雀鲷科的黑边光鳃鱼原产于马卡罗尼西亚群岛（亚速尔群岛、马德拉群岛和加那利群岛）以及非洲西海岸塞内加尔和安哥拉之间的海域。在2008年和2009年的南半球夏季，首次在巴西圣卡塔琳娜州弗洛里亚诺波利斯的坎佩切岛和哈维尔群岛附近的西南大西洋记录到该物种。在此，利用目视计数和基因调查描述了黑边光鳃鱼在巴西南部水域的扩散情况，并对本地同属的多线光鳃鱼密度的变化进行了调查。2009年至2014年对这两种光鳃鱼进行了水下目视普查。采集了黑边光鳃鱼的组织样本，对线粒体DNA控制区进行了测序，并与自然分布区的线粒体DNA单倍型进行比较，以确认物种身份、比较遗传多样性并推断新建立的巴西种群之间的连通性。在过去5年里，巴西的黑边光鳃鱼种群显著增加，其对多线光鳃鱼的影响仍是一个悬而未决的问题，需要更长时间序列的数据来阐明可能的相互作用。分子分析确认了物种身份揭示了巴西各研究地点之间强大的单倍型连通性，并表明与本地种群相比，巴西的遗传多样性较低，这表明只有少数个体开始了此次入侵。有四种假说可以解释这一殖民事件：黑边光鳃鱼是由水族馆饲养者放生的；幼体或幼鱼通过船舶压载水运输；该物种是与石油钻井平台一起漂浮过来的；它们通过正常的幼体扩散或与漂浮物一起自然漂浮穿越了大西洋。漂浮假说是最有可能的，但所有四种可能性都有道理，并且可能同时发生。
