大亚湾鱼类生物量粒径谱特征

为了解大亚湾海域鱼类群落粒径结构特征,根据2016年底拖网调查数据构建了春、秋季大亚湾鱼类粒径谱,比较分析了两个季节鱼类生物量粒径谱特征参数异质性。结果表明,大亚湾鱼类的Sheldon型生物量粒径谱为单峰模式,鱼类粒径范围为-2～10粒径级,最高峰值均位于3～4粒径级。鱼类标准化生物量粒径谱曲线陡峭及曲率降低主要是少量粒径大的常年定居性鱼种龙头鱼(Harpodon nehereus)、二长棘犁齿鲷(Evynnis cardinalis)和季节洄游性鱼类鳗鲇(Plotosus lineatus)、金钱鱼(Scatophagus argus)出现以及粒径范围减小造成的。从沿岸、中部和湾口等3个区域来看,春季,沿岸海域曲率最大,湾中部海域次之,湾口海域最小;秋季,湾口海域曲率最大,沿岸海域次之,湾中部海域最小。沿岸海域曲率降低主要是有大量粒径小的当年生短吻鲾(Leiognathus brevirostris)幼鱼出现造成;中部海域曲率降低主要是有少数粒径较大的杂食豆齿鳗(Pisoodonophisboro)和常年定居种龙头鱼的出现造成;湾口海域曲率升高主要是有少数粒径大的龙头鱼的出现造成。可见,洄游性鱼类、当年生幼鱼和常年定居性鱼类等补充群体数量及粒径范围大小对鱼类粒径谱的峰型和曲率具有明显的影响。ABC曲线表明,春、秋季大亚湾海域鱼类群落均处于严重干扰状态。

Biomass particle size spectrum of fish in Daya Bay

In order to understand the grain-size structure characteristics of fish communities in Daya Bay, we constructed the biomass particle-size spectrum of fish in Daya Bay based on the data from two bottom trawl surveys in 2016. The heterogeneity of the characteristic parameters of the fish biomass particle-size spectrum from different parts of the bay in two seasons was compared and analyzed. The results showed that the pattern of the Sheldon-type biomass particle-size spectrum of fish in Daya Bay was unimodal; the fish particle size ranged from -2 to 10 and the highest peak was at a grain size of 3-4. The reduction in the curvature of the biomass particle-size spectrum of fish was mainly caused by the reduced size range from the emergence of a small number of large perennial settlers, Harpodon nehereus and Evynnis cardinalis, and seasonal migratory fish, Plotosus lineatus and Scatophagus argus. From the three areas of the bay (coastal, central, and bayou), the curvatures in the spring were the largest in the coastal area, followed by the central area, and they were the smallest in the bayou. The curvatures in autumn were the largest in the bayou, followed by the coastal area, and they were the smallest in the central area of the bay. The decrease in the curvature of the coastal area was mainly caused by the presence of a large number of small particle Leiognathus brevirostris juveniles. The decrease in the curvature of the central area was due to the emergence of a small number of large Pisodonophis boro and Harpadon nehereus, which reduced the size range. The increase in the curvature in the bayou was mainly caused by the emergence of a small number of large Harpadon nehereus. It can be seen that the number of supplemental groups such perennial settler fish, migratory fish, and perennial juveniles, and the size ranges have a significant impact on the peak shape and curvature of the fish biomass particle-size spectrum. The ABC curve showed that the biomass particle-size spectrum of fish in spring and autumn were in a seriously disturbed state.