莱州湾鱼类群落同功能种团的季节变化

利用2011年5月、8月、10月和12月底拖网调查数据,对莱州湾海域鱼类同功能种团特征及其季节变化进行了研究。全年调查共渔获鱼类49种,全部为硬骨鱼类。根据鱼类的摄食习性,调查海域鱼类可划分为浮游动物食性种团、浮游动物/底栖动物食性种团、底栖动物食性种团、底栖动物/游泳动物食性种团、游泳动物食性种团、杂食性种团和碎屑食性种团共7个同功能种团,其中底栖动物食性种团种类数最多(14种),底栖动物/游泳动物食性种团次之(12种)。碎屑食性种团生物量在全年处于第一优势地位,占32.8%;其次为浮游动物食性种团,占31.6%;再次为底栖动物/游泳动物食性种团,占25.0%。同功能种团多样性(HFD)和种类多样性(Hs)季节变化趋势相同,均在夏季达到最高值,冬季达到最低值;两者关系使用指数方程拟合效果最佳。浮游动物食性种团平均营养级为3.71、浮游动物/底栖动物食性种团为3.83、底栖动物食性种团为3.43、底栖动物/游泳动物食性种团为3.75、游泳动物食性种团为3.86、杂食性种团为3.73、碎屑食性种团为3.34。与20世纪80年代、90年代调查结果相比,目前莱州湾碎屑食性种团比例明显上升,游泳动物食性种团比例大幅下;底栖动物食性种团和游泳动物食性种团的平均营养级明显下降,碎屑食性种团平均营养级有所上升。

Seasonal changes of functional guilds of fish community in Laizhou Bay, East China

Character and its change of functional guilds of fish community in Laizhou Bay was studied based on trawl survey data from bottom trawl surveys in May, August, October and December 2011. A total of 49 species were identified, all of them were Osteichathyes species. It can be divided into seven guilds based on the feeding habit: planktivores, planktivores/benthivores, benthivores, benthivores/piscivores, piscivores, omnivores and detritivores. The most species-rich guild was benthivores (14 species) and benthivores/piscivores (12 species). Detritivores (32.8%), planktivores (31.6%) and benthivores/piscivores (25.0%) accounted for about 90 percentages of the total catch. The seasonal trends of diversity of functional guilds (H_FD) were same as that of diversity of species (H_S). Exponential equation fitted perfectly between H_FD and H_S. The average trophic level of every guild was all between 3 and 4. Compared with the results conducted in 1980s and 1990s, the change was: 1.The proportion of detritivores increase and the average trophic level also raise; 2.The proportion of piscivores decline and average trophic level also down.