岱衢洋渔业动物多样性分析

根据2007年4—11月对岱衢洋进行的4个航次的底拖网、定置刺网与蟹笼调查数据,分析了该海域渔业动物物种的多样性及其资源动态。结果表明:(1)3种作业方式共发现渔业动物98种,其中,鱼类57种、虾蟹类32种、头足类3种、其他类6种,隶属于4门7纲20目53科。(2)底拖网调查共发现渔业动物68种,分别为鱼类38种、虾蟹类23种、头足类2种、其他类5种,隶属于4门7纲18目42科;4月份的物种丰富度指数(D)与8月份、11月份之间存在显著差异(P<0.05);总生物量与总尾数密度的最大值都出现在8月份,且与5月份、11月份均存在显著性差异(P<0.05);龙头鱼在4个调查月份中均为优势种,其中8月份的平均体重与其他3个月份之间差异显著(P<0.05)。根据底拖网调查结果,岱衢洋渔业动物群落以暖温性鱼类与广温广盐性甲壳类(虾蟹类与其他类中的口虾蛄)为主,种类数较少,多样性(H′)较低(P<0.01)。

ANALYSIS ON THE SPECIES DIVERSITY OF FISHERY ANIMALS IN DAIQUYANG

The Daiquyang locates between the Daishan and Qushan Islands in the Zhoushan Archipelago.Due to its optimal location and suitable environmental characteristics,it is the spawning and feeding ground of Larimichthys crocea of the Daiqu Race,and also of other fishery animals(fish species such as Larimichthys polyactis,Trichiurus japonicus,Pampus argenteus and Engraulis japonicus,crustacean species such as Portunus trituberculatus,Charybdis japonica,Exopalaemon carinicauda,Acetes chinensis and Oratosquilla oratoria,cephalopods such as Sepiella maindroni,Octopus variabilis,Octopus ocellatus and Loligo duvaucelii,and other animal species such as Nassarius variciferus,Sliqua minima,Cantharus cecillei and Moerella irideseens).For a long time,although the Daiquyang plays an important role in marine fisheries in the East China Sea,there have been no studies focused on the species diversity of its fishery animals.In recent years,both the environment and fishery resources in the Daiquyang have been facing new threats arisen from rapid development of harbor industries and a mass of shore reclamation in the Zhoushan Archipelago District,Zhejiang.Therefore it is necessary to study the species diversity of fishery animals in this area.We analyzed fishery animal diversity and the status of fishery resources based on four surveys conducted by bottom trawl,setting gillnet and crab pot from April to November 2007 in the Daiquyang.Three analytical methods including sweep-area method,biodiversity analysis and analysis of variance were used.The results showed that: 1) a total of 98 fishery animals were sampled,including fishes(58 species),crustaceans(32 species),cephalopods(3 species) and other species(6 species),belonging to 53 families of 20 orders,7 classes and 4 phylums.2) In our trawl collections,a total of 68 fishery animals were obtained,including fishes(38 species),crustaceans(23 species),cephalopods(2 species) and other species(5 species),belonging to 42 families of 18 orders,7 classes and 4 phylums.The richness index(D) of fishery animals in April was significantly different from those in August and November(P <0.05).Both the biomass and the number abundance density indices of fishery animals were the highest in August,significantly different from those in May and November(P <0.05).The dominant species were Harpodon nehereus,Coilia mystus,Palaemon gravieri and Alpheus japonicus in April,Harpodon nehereus,Coilia mystus,Exopalaemon annandalei and Charybdis japonica in May,Harpodon nehereu and Portunus trituberculatus in August,Harpodon nehereus,Charybdis japonica and Oratosquilla oratoria in December,and among them,Harpodon nehereus was the dominant species during all study months.Average body weight of Harpodon nehereus in August was significantly different from those in other three months(P <0.05) because of the spawning of the juveniles.For trawl collections,the biological community was mainly composed of warm temperature fish species,eurythermal and euryhaline crustacean species(such as Harpodon nehereus,Coilia mystus,Alpheus japonicus,Portunus trituberculatus and Oratosquilla oratoria) with a small number of fishery animals and lower Shannon-Wiener diversity index(H′),compared with offshore waters and deep waters in the East China Sea,In addition,its biomass was closely related with the bottom water temperature(P <0.01).