乐清湾贝类群落组成及其粒径谱结构特征

为了解乐清湾贝类资源情况及群落稳定性特征，基于2016—2017年乐清湾定点调查数据，分析了不同季节乐清湾贝类组成、优势种、资源密度、以及物种多样性，并首次建立乐清湾海域贝类生物量粒径谱与标准化生物量粒径谱。结果显示：1)本次共采集到贝类共计45种，隶属于12目，25科，31属。焦河蓝蛤(Potamocorbula ustulata)为乐清湾绝对优势种；2)资源密度表现为夏季最高，其次为春季，秋季与冬季次之；4个季节的丰富度指数(D)、多样性指数(H′)和均匀度指数(J′)平均为3.26、1.61、0.45,3种多样性指数均处于较低水平；3)ABC曲线显示乐清湾贝类的生物群落处于中度干扰状态；4)乐清湾生物量粒径谱谱型复杂，优势种控制着生物量粒径谱的峰值，且与我国其他海域的结果也存在差异；5)标准化生物量粒径谱的斜率范围为-1.5539—-0.7373,在我国近海海域中属于偏低水平，表明营养循环水平较低。截距范围在16.673—21.597,高于我国其他海域，说明乐清湾贝类生产力水平较高。

Analysis on community structure of shellfish and its characteristics of biomass particle size spectrum in Yueqing Bay, China

The sediment environment is the cultured area for shellfish mudflats, its quality will directly affect the survival of shellfish. Shellfish is a filter feeding animal with powerful filtering ability. In recent years, with the rapid development, the mudflat deterioration of the environment threatens shellfish''s living severely. As a result, the shellfish community was changed. Therefore, understanding the resource biomass changes is especially important for policy-makers. The research provides scientific evidence for protecting the marine resources and sustainable development. It discusses the resource and community stability by abundance-biomass curve and size spectra. One point should be noted that the biomass size spectrum (BSS) and normalized biomass size spectra (NBSS) were applied to the shellfish community firstly. In some ways, the BBS method is easier to achieve, in which calculation errors caused by inaccurate shellfish identification may be avoided. In order to understand the marine ecosystems, the fields of application for the BSS theory have been adopted into benthic communities, fish and so on. The species composition, dominance, resource biomass and density and community diversity were studied using data collected from four surveys from May 2016 to February 2017 in Yueqing Bay, Zhejiang Province. The main results showed that 45 shellfish species were identified, which belonged to 12 orders, 25 families and 31genera. The absolute dominant species was Potamocorbula ustulata; the level of resource biomass and density was the highest level in summer, followed by winter, spring and autumn. The average values for species abundance index (D), species diversity index (H'') and species evenness index (J'') were 3.26, 1.61 and 0.45, respectively, indicating that shellfish community diversity was on a low level. The ABC curve showed that the shellfish community was unstable. The biomass size spectrum was complicated, which dome was controlled by dominant species. Compared with other Chinese offshore areas, it was also different from others results. The slopes of NBSS ranged from -1.5539 to -0.7373, and the intercepts ranged from 16.673 to 21.597. The slope values were lower than those of most other area of Chinese offshore area, and it stood for a lower circulatory efficiency of nutrients in Yueqing Bay. In addition, the intercept values inferred that the production in Yueqing Bay was higher than other Chinese offshore areas. As an ecological research method, biomass particle size spectrum can compare the productivity levels of different ecosystems, describe the trend of biomass change, and is very sensitive to environmental changes, providing a new way to understand the biological law at different levels and environmental monitoring.