Genetic structure and diversity of the Chilean flat oyster Ostrea chilensis (Bivalvia: Ostreidae) along its natural distribution from natural beds subject to different fishing histories

Abstract Ostrea chilensis (Küster, 1844), the flat oyster, is native to Chile and New Zealand. In Chile, it occurs in a few natural beds, from the northern part of Chiloé Island (41 ºS) to the Guaitecas Archipelago (45 ºS). This bivalve is slow growing, broods its young, and has very limited dispersal potential. The Ostrea chilensis fishery has been over-exploited for a number of decades such that in some locations oysters no longer exist. The aim of this study was to study the genetic diversity of the Chilean flat oyster along its natural distribution to quantify the possible impact of the dredge fishery on wild populations. The genetic structure and diversity of Ostrea chilensis from six natural beds with different histories of fishing activity were estimated. Based on mitochondrial (Cytb) and nuclear (ITS1) DNA sequence variation, our results provide evidence that genetic diversity is different among populations with recent history of wild dredge fishery efforts. We discuss the possible causes of these results. Ultimately, such new information may be used to develop and apply new management measures to promote the sustainable use of this valuable marine resource.

摘要：智利扁牡蛎（Ostrea chilensis, Küster, 1844）又名扁平牡蛎，原产于智利与新西兰。在智利境内，该物种分布于奇洛埃岛北部（南纬41°）至瓜伊特卡斯群岛（南纬45°）的少量天然牡蛎床中。这种双壳类软体动物生长缓慢、具有育幼习性，且扩散潜力极低。数十年来，智利扁牡蛎渔业长期遭受过度捕捞，部分区域的野生种群已不复存在。本研究旨在沿其自然分布范围调查智利扁牡蛎的遗传多样性，以量化拖曳耙网捕捞对野生种群的潜在影响。研究对6个具有不同捕捞活动历史的天然牡蛎床的智利扁牡蛎种群的遗传结构与多样性进行了评估。基于线粒体（细胞色素b，Cytb）与细胞核（内转录间隔区1，ITS1）的DNA序列变异数据，本研究结果显示，存在近期野生拖网捕捞历史的种群间遗传多样性存在显著差异。本文将对该结果的潜在成因展开讨论。综上，本研究获得的新信息可用于制定并实施针对性管理措施，以促进这一珍贵海洋资源的可持续利用。