雷州半岛沿岸海域浮游桡足类的分布特征及其影响因素

DISTRIBUTION CHARACTERISTICS OF PLANKTONIC COPEPODS AND ITS INFLUENCING FACTORS IN THE COASTAL WATERS OFF LEIZHOU PENINSULA

根据2017年10月和2018年1、5、7月对雷州半岛沿岸海域浮游动物四个季度的调查数据,分析了浮游桡足类群落组成的季节变化及其影响因素。结果共鉴定出浮游桡足类80种,其中哲水蚤目55种,占总种类数的68.7%;剑水蚤目21种,占总种类数的26.2%;猛水蚤目3种,占总种类数的3.8%;鱼虱目1种,占总种类数的1.3%;种类数冬春季最多,各有45种,夏季40种,秋季最少仅29种;各季节间共有种数在18~25种之间,季节更替率变化范围为53.2%~67.9%。优势种有9种,均隶属于哲水蚤目,分别是红纺锤水蚤(Acartia erythraea)、太平洋纺锤水蚤(Acartia pacifica)、汤氏长足水蚤(Calanopia thompsoni)、微刺哲水蚤(Canthocalanus pauper)、瘦尾胸刺水蚤(Centropages tenuicermis)、小拟哲水蚤(Paracalanus parvus)、亚强次真哲水蚤(Subeucalanus subcrassus)、锥形宽水蚤(Temora turbinata)和真刺水蚤幼体(Eucharta larva),无全年优势种,季节更替明显。多样性指数变化范围在0.30~3.20之间,平均为1.68;均匀度变化范围为0.16~0.99,平均为0.70。桡足类丰度变化范围为0.09~790.95ind./m^(3),平均为34.94ind./m^(3),平均值春季最高,达60.92 ind./m^(3),冬季次之,为43.93 ind./m^(3),夏季为22.44 ind./m^(3),秋季最低,仅为12.47 ind./m^(3)。丰度的平面分布显示:雷州半岛南部沿岸海域4季均出现明显密集区,东部沿岸海域整体高于西部,西南部的丰度最低,与各区域的生物资源和环境因素密切相关;相关分析显示,秋季、冬季和春季桡足类丰度与水温和盐度均呈非显著负相关,夏季与盐度呈极显著正相关,冬季与叶绿素a含量呈显著正相关。

Based on the four seasonal survey data of zooplankton in the coastal waters off Leizhou Peninsula in October 2017 and January,May,and July 2018,seasonal changes in composition of the planktonic copepod community and influencing factors were analyzed.Eighty species of planktonic copepods were identified,including 55 species of Calanoida,accounting for 68.7%of the total number of species,followed by 21 species of Cyclopoida(26.2%),3Harpacticoida(3.8%),and one Caligidae(1.3%).The largest number of species were found in winter and spring,with 45species each,followed by summer(40 species),and autumn(29 species).The number of species in common among seasons was 18~25,with a seasonal replacement rate of 53.2%~67.9%.Nine dominant species were found,namely,Acartia erythraea,Acartia pacifica,Calanopia thompsoni,Canthocalanus pauper,Centropages tenuicermis,Paracalanus parvus,Subeucalanus subcrassus,Temora turbinata,and Eucharta larva.They all are Calanoida and varied seasonally with no one species occurred all year round in dominant species.The diversity index ranged 0.30~3.20,on average value of 1.68.The evenness index ranged 0.16~0.99,on average of 0.70.The abundance of copepods ranged 0.09~790.95 ind./m^(3) on average of 34.94 ind./m^(3),and the average was the highest in spring(60.92 ind./m^(3)),followed by winter(43.93 ind./m^(3)),summer(22.44 ind./m^(3)),and autumn(12.47 ind./m^(3)).In horizontal distribution,the annual copepods density was high in the southern coastal waters off Leizhou Peninsula,higher in the eastern region than in the western,and the lowest density in the southwestern sea.The horizontal distribution was closely related to the biological resources and environmental factors in each region.At last,the correlation analysis revealed that copepod abundance had no significant negative correlation with water temperature and salinity in autumn,winter,and spring,a very significant positive correlation with salinity in summer,and a significant positive correlation with chlorophyll a in winter.