西沙东岛珊瑚礁鱼类种类组成特征与演变

THE CHARACTERISTICS OF SPECIES COMPOSITION AND SUCCESSION OF CORAL REEF FISHES IN XISHA EAST ISLAND

  • 摘要: 为更好保护和管理东岛珊瑚礁鱼类资源, 2021和2022年通过水下摄影和水下潜水捕捞对东岛珊瑚礁鱼类进行现场调查, 并结合历史研究探讨了东岛珊瑚礁鱼类种类组成及历史演变特征, 结果如下: 东岛共发现珊瑚礁鱼类235种, 隶属于辐鳍鱼纲(Actinopterygii; 222种)和软骨鱼纲(Chondrichthyes; 13种), 由16目、55科组成, 其中鲈形目(Perciformes)鱼类最多, 为181种, 科层面, 蝴蝶鱼科(Chaetodontidae)和鹦嘴鱼科(Scaridae)最多, 均22种。东岛珊瑚礁鱼类物种数与其对应的最大全长成指数相关, 随其增加而显著减少。东岛以小型鱼类最多, 占总种类数的38.72%; 其次是中型鱼类, 为34.47%; 大型鱼类为26.81%。从食性类型来看, 东岛肉食性鱼类最多, 占物种数的56.60%。各时间段之间鱼类的相似性指数均较低, 证实了鱼类发生了显著的演替变化。研究较历史共有103种鱼类未发现, 其中, 肉食性鱼类占未发现鱼类的74.76%, 同时未发现大型鱼类几乎全部分布在肉食性鱼类中; 14种位列于IUCN红色名录的鱼类, 除一种外, 其他均在此研究中未发现并均为大型鱼类, 以上表明东岛鱼类出现了过度捕捞。未发现的小型鱼类中有70.97%物种为念礁性鱼类, 并发现长棘海星, 表明东岛珊瑚礁海域正遭受生境退化影响。研究结果为珊瑚礁鱼类的演替趋势提供了基础参考, 为珊瑚礁生态系统的修复、保护和管理提供基础数据。

     

    Abstract: The East Island is the second largest island of Xisha Islands, which is a typical coral reef island, and the coral reef is known as the tropical rain forest in the ocean and high biodiversity. In order to better protect and manage the coral reef fish resources in East Island, we investigated the coral reef fish through underwater video and underwater diving fishing, and systematically discussed the species composition and historical evolution characteristics of coral reef fish in combination with historical research in 2021 and 2022. The results were as follows, at present, 235 species of coral reef fish were found in the East Island, belonging to Osteichthys (222 species) and Chondrichthyes (13 species), which were composed of 16 orders and 55 families, of which Perciformes had the largest number of 181 species, and Chaetodontidae and Scaridae had the largest number of 22 species. The correlation between the number of fish species in the coral reef of East Island and its corresponding maximum total length index decreased significantly with the increase of the maximum total length. Small-sized fish was the most common in East Island, accounting for 38.72% of the total species; the second was medium-sized fish, 34.47%; 26.81% of large-sized fish. According to the type of feeding habits, East Island had the largest number of carnivorous fish, 133 species, accounting for 56.60% of the total species; there was little difference between omnivorous and herbivorous fishes, which were 52 and 50 species respectively. From the perspective of similarity, the similarity index between different time periods was low, which confirmed that fish had undergone great succession changes. The comparison between this study and the historical survey shows that there were 103 species of fish that had not been found, especially carnivorous fish, accounting for 74.76% of the undiscovered fish; in this study, 40 species of undiscovered large-sized fish were almost all carnivorous fish, both of which indicate that fish are overfishing. At the same time, 14 species of fish in the coral reef of East Island were listed in the IUCN Red List. Except for one species, others were not found in this study, and all were large fish, which supported the theory that large fish were easy to be extinct. 70.97% of the undiscovered small fish species were reef fish, and long spined starfish were found, both of which indicate that the coral reef waters of East Island were also affected by habitat degradation. The results of this study provide a basic reference for the succession trend of coral reef fish and basic data for the restoration, protection and management of coral reef ecosystem.

     

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