春末夏初莱州湾浮游动物生物量谱及潜在鱼类生物量的估算

Zooplankton biomass size spectra and prediction of fish biomass in late spring in Laizhou Bay, Bohai Sea

关键词:  浮游动物  生物量谱  潜在鱼类  生物量估算  莱州湾

Key words:  Zooplankton  Biomass size spectrum  Prediction of fish biomass  Laizhou Bay

摘要:

分析了2008年春末夏初（5月和6月）利用浮游生物网（孔径160和500μm）采集的莱州湾浮游动物样品，对此季莱州湾浮游动物的生物量——个体粒级分布和生产力进行研究，构建了莱州湾浮游动物的标准生物量谱，并应用生物量谱理论Borgmann 模型(1987)对莱州湾的渔业资源现存量进行了初步的估算。结果表明，5月和6月莱州湾浮游动物个体粒级（Log2含碳量）分布范围为-3~10。浮游动物的Sheldon 型生物量谱的特征为：5月生物量高，表现为由双刺纺锤水蚤和中华哲水蚤、强壮箭虫构成的双峰曲线；6月生物量低，表现为由中华哲水蚤、强壮箭虫构成的单峰曲线。浮游动物混合粒级的日生产力和日周转率P/B值：5月为75 mg C/m2•d和0.20，6月为24 mg C/m2•d和0.16。5月的标准生物量谱线性方程y = -0.962 9x + 14.893 (R2=0.60)，6月y = -0.906 3x + 12.832(R2 = 0.80)。基于Borgmann 模型的估算，5月粒级为14~16的渔业生物的生物量为0.57gC/m2，6月粒级12~25的渔业生物的生物量为0.1 gC/m2。

Abstract:

Biomass size distributions of zooplankton in the Laizhou Bay,Bohai Sea, were analyzed based on the samples collected by plankton nets (mesh size of 160μm and 500μm) in May and June, 2011. Results showed that, in both months, zooplankton individuals from samples were in the size range of -3~10 (in logarithmatic carbon unit), and continuous Sheldon-type biomass size spectra without gaps were found similarly. But in May, Sheldon-type biomass size curve was composed of two major domes attributed by small copepod Acartia bifilosa and meso-individuals, Calanus sinicus, Sagitta crassa respectively. While in June, it had only one remarkable dome attributed by meso-individuals, C. sinicus and S. crassa. Total zooplankton biomass in June was much lower than that in May as the A. bifilosa declined greatly. Moreover, the production and P/B of zooplankton were calculated as 75 mg C/m2•d, 0.20 for May and 24 mg C/m2•d, 0.16 for June. Normalized biomass size spectra were also constructed on a double log plot and fitted closely with a linear regression line with equations y = -0.962 9x +14.893 (R2=0.60) for May and y=-0.906 3x+12.832 (R2 = 0.80) for June. According to theoretical Borgmann model (1987), the fish biomass is predicted to be 0.57 gC/m2 in the size range of 14~16 in May and 0.1 gC/m2 in the size range of 12~25 in June.