Institute of Ocean and Earth Sciences, Universiti Malaya , 50603, Kuala Lumpur, Malaysia.
Institute of Biological Sciences, Universiti Malaya , 50603, Kuala Lumpur, Malaysia.
Sci Rep. 2021 Jul 21;11(1):14874. doi: 10.1038/s41598-021-94257-7.
The demersal brown banded bamboo shark Chiloscyllium punctatum is a major component of sharks landed in Malaysia. However, little is known about their population structure and the effect of high fishing pressure on these weak swimming sharks. Both mitochondrial DNA control region (1072 bp) and NADH dehydrogenase subunit 2 (1044 bp) were used to elucidate the genetic structure and connectivity of C. punctatum among five major areas within the Sundaland region. Our findings revealed (i) strong genetic structure with little present day mixing between the major areas, (ii) high intra-population genetic diversity with unique haplotypes, (iii) significant correlation between genetic differentiation and geographical distance coupled with detectable presence of fine scale geographical barriers (i.e. the South China Sea), (iv) historical directional gene flow from the east coast of Peninsular Malaysia towards the west coast and Borneo, and (v) no detectable genetic differentiation along the coastline of east Peninsular Malaysia. Genetic patterns inferred from the mitochondrial DNA loci were consistent with the strong coastal shelf association in this species, the presence of contemporary barriers shaped by benthic features, and limited current-driven egg dispersal. Fine scale population structure of C. punctatum highlights the need to improve genetic understanding for fishery management and conservation of other small-sized sharks.
底栖棕带竹鲨 Chiloscyllium punctatum 是马来西亚上岸鲨鱼的主要组成部分。然而，人们对其种群结构以及高强度捕捞压力对这些游泳能力较弱的鲨鱼的影响知之甚少。本研究使用线粒体 DNA 控制区（1072bp）和 NADH 脱氢酶亚单位 2（1044bp）来阐明桑达兰地区五个主要区域内的 C. punctatum 的遗传结构和连通性。研究结果表明：（i）遗传结构较强，主要区域之间目前混合程度较低；（ii）种群内遗传多样性高，具有独特的单倍型；（iii）遗传分化与地理距离之间存在显著相关性，并伴有可检测到的细尺度地理障碍（即南海）的存在；（iv）存在从马来半岛东海岸向西海岸和婆罗洲的历史定向基因流；（v）在马来半岛东海岸的海岸线没有可检测到的遗传分化。从线粒体 DNA 基因座推断的遗传模式与该物种与沿海大陆架的强烈关联、由底栖特征形成的现代障碍以及有限的海流驱动的卵扩散相一致。C. punctatum 的细尺度种群结构强调了需要提高对渔业管理和其他小型鲨鱼保护的遗传认识。
