北部湾口海域鱼类分类多样性的初步探讨

摘要

Based on the data collected from two bottom trawl surveys in spring and autumn respectively in the mouth of Beibu Bay from 2012 to 2013,we systematically analyzed the species composition of fish in the survey sea area, and calculated the index of relative importance (IRI),inclusion index at taxonomic level (TINCLi )and taxonomic diversity index (△+and ∧+).The results showed that there were 301 fish species in 195 genera,100 families, and 26 orders,among them Perciformes was dominate species,and 75 fish species were found in both two surveys. The number of dominant species in autumn was significantly less than that in spring,indicating a remarkable sea-sonal changes of dominate species.Most dominant species were small and medium sized fish.Analysis of the inclu-sion index at taxonomic level showed that the average numbers of (families,genera,species),(genera,species) and (species)per order,family and genus in the mouth of Beibu Bay were (3.85,7.50,11.58),(1.95,3.01) and (1 .54),respectively.The taxonomic diversity of fish species was relatively low in the species level,the distri-bution was relatively centralized and the genetic relationship was relatively close.The values of△+and∧+in the mouth of Beibu Bay were 46.34 and 47.82,respectively.The value of△+was closer to that in Beibu Bay,com-pared with those in Yellow Sea and Bohai Sea,East China Sea and the waters of southwestern Nansha Islands.It indicated that the genetic relationship between fish species in the mouth of Beibu Bay and Beibu Bay was closer. However,obvious changes of△+value with latitude were not found in this sea area under large scale distribution patterns.%根据2012～2013年在北部湾口海域秋、春两个航次的调查数据，系统地分析了调查海域鱼类种类组成，并分别计算该海域鱼类的相对重要性指数（IRI）、分类阶元包涵指数（TINCLi ）及分类多样性指数（△＋和∧＋）．结果显示，此次调查共捕获鱼类26目100科195属301种，其中以鲈形目鱼类占据绝对优势，两个季节同时被捕获鱼类75种．秋季优势种类数明显低于春季，且均以中小型鱼类为主，种类更替现象明显．TINCLi 研究结果表明，研究海域鱼类种类组成目、科、属所分别拥有的（科、属、种）、（属、种）和（种）的平均数目分别为（3．85、7．50、11．58）、（1．95、3．01）和（1.54），在种级水平上，该海域的鱼类分类多样性较低，分布相对集中，亲缘关系较近．北部湾口海域的△＋和∧＋值分别为46．34和47．82，相比较于黄渤海、东海和南沙群岛西南部海域，其△＋值最接近于北部湾，表明二者间鱼类的亲缘关系比较近；但在大尺度范围内，该海域△＋值并未表现出明显随纬度变化的规律．