南海东沙岛及太平岛鱼类种类组成和动物地理学特点

Species composition and geographical distribution of fishes in Tungsha Island and Taiping Island in the South China Sea

就笔者等在南海之东沙岛及太平岛两处海域所调查记录到的珊瑚礁鱼类,连同自1975年以来之文献与数据库的记录作综合整理。结果表明,东沙岛有73科652种,太平岛有56科466种,两岛合计共有76科759种。太平岛所记录的总鱼种数较东沙岛为少,主要原因纯系因太平岛之礁域面积较小,且调查次数甚少之故。根据各鱼种地理分布范围之分析,发现在此二岛所记录到的鱼种几乎全部都是印度–太平洋、印度–西太平洋及西太平洋等广泛分布的鱼种,目前只有黄头刻齿雀鲷(Chrysiptera chrysocephala)1种是只在南海发现之鱼种。由此可推测南海的鱼类相应与周边海域或珊瑚三角的鱼类相充分交流,并未有明显隔离或种化的现象。东沙岛及太平岛鱼类相之S rensen相似性系数值虽已达85.69%,但其中仍有240种是只分布在东沙岛及台湾(165种),或太平岛及台湾(75种),而未在另一岛屿发现之鱼种,且其中只在太平岛及东沙岛发现的21种及20种鱼中,大多为稀有种,非常不容易被调查到。故推测目前在此二岛所作的调查频度相当不足,如果调查能更密集更长期,则两岛的鱼相会更相似。

This paper summarizes all the reef fishes collected in Tungsha（Pratas） Island and Taiping Island（Nansha or Spratly） in the South China Sea,along with records of these two islands from literatures and da-tabases since 1975.A total number of 73 families and 652 species in Tungsha Island as well as 56 families and 466 species in Taiping Island were obtained,with 76 families and 759 species found in both Islands.The reason why the species number in Taiping is less than that of Tungsha is because the reef area of Taiping is much smaller and fewer surveys were conducted.Based on the analysis of zoogeographical distribution range of each species,we found that almost all the species recorded in the two islands are widely distributed spe-cies in Indo-Pacific,Indo-western Pacific and western Pacific.Only one species,Chrysiptera chrysocephala,was found only in the South China Sea.This result infers that the fish fauna in the South China Sea can fully exchange with that in the surrounding waters or the Coral Triangle region,and any geographical isolation or speciation phenomenon is not discernible.In addition,although the S？rensen similarity index between Taip-ing and Tungsha reached 85.69%,a total of 240 species is absent from either Taiping or Tungsha,i.e.165 species were recorded in both Tungsha and Taiwan but absent at Taiping,and 75 species were recorded in both Taiping and Taiwan but absent at Tungsha.Furthermore,most of the 21 and 20 species which were re-corded only in Taiping and Tungsha,respectively,are hard-to-survey rare species.We speculate that our sur-veys in both islands are rather insufficient.If the investigation could be more intensive and longer-term,the similarity of fish faunas between these two islands will be even higher.