山东半岛南部海域鱼类群落生物量粒径谱季节变化

Seasonal Variation of Biomass Size Spectra of Fish Communities in the Southern Waters off Shandong Peninsula

为了解山东半岛南部海域鱼类群落粒径结构特征,本文根据2016—2017年渔业资源底拖网季度调查数据,构建了山东半岛南部海域鱼类生物量粒径谱,分析了该海域鱼类群落的粒径结构特征及其季节变化。研究表明,山东半岛南部海域Sheldon型鱼类生物量粒径谱呈双峰模式,鱼类粒径范围为2~12粒径级,粒径分布相对均匀,出现波峰的粒径区间存在季节差异,春、夏季第一个波峰出现在3~4粒径级,主要由细纹狮子鱼(Liparis tanakae)、方氏云鳚(Pholis fangi)和大泷六线鱼(Hexagrammos otakii)等种类组成。秋、冬季第一个波峰出现在5~6粒径级,主要由小眼绿鳍鱼(Chelidonichthys spinosus)、长蛇鲻(Saurida elongata)和斑鰶(Konosirus punctatus)等种类组成。四个季节的第二个波峰均由细纹狮子鱼、黄鮟鱇(Lophius litulon)和大头鳕(Gadus macrocephalus)等鱼类个体组成。全部鱼类群落标准化生物量粒径谱的斜率和截距存在季节差异,其中夏季粒径谱陡峭,截距值显著高于其他季节,而冬季粒径谱最平缓,截距值最小,粒径谱斜率和截距的变化主要受当年生幼鱼群体的影响。在山东半岛南部海域,底层鱼类群落与全部鱼类群落的标准化生物量粒径谱的变化趋势相似。在同一季节,底层鱼类群落与全部鱼类群落的标准化生物量粒径谱斜率和截距之间无显著性差异(P>0.05),而暖温性鱼类群落与全部鱼类群落之间存在显著性差异(P<0.05)。山东半岛南部海域的全部鱼类群落粒径结构以小粒径鱼类为主,大型鱼种和大个体较少。鱼类的种类组成有明显的季节变化,当年生幼鱼及洄游性鱼类的个体数量变化是影响该海域鱼类群落粒径结构的主要因素。

To understand the size structure characteristics of fish communities in the southern waters off Shandong Peninsula,the biomass size spectra of fish communities were constructed based on the data collected from seasonal bottom trawl surveys in the southern waters off the Shandong Peninsula from 2016 to 2017.The characteristics parameters of biomass size spectra of fish communities in four seasons were analyzed.The Sheldon biomass size spectra of fish communities in the southern waters off Shandong Peninsula displayed a bimodal pattern with the fish particle size ranging from 2 to 12,relatively uniform.The size ranges with the biomass peak varied among seasons.The first biomass peak in spring and summer contained the particle size ranges between 3 and 4,and consisted of the fish species including Liparis tanakae,Pholis fangi,Hexagrammos otakii among others.The first biomass peak in autumn and winter contained the particle size ranges between 5 and 6,and were composed of fish species like Chelidonichthys spinosus,Saurida elongate,Konosirus punctatus among others.The second biomass peak in four seasons were composed of fish species like Liparis tanakae,Lophius litulon,Gadus microcephalus among others.Both the slope and intercept of the normalized biomass size spectra(NBSS)of all fish communities showed significantly seasonal changes.The absolute values of the slope and intercept of all fish assemblages in summer were significantly higher than those in other seasons while these values in winter were significantly lower than those in other seasons.The annual changes of the slope and intercept of NBSS were mainly affected by recruitment,especially the young fish individuals.In general,the NBSS of demersal fish species showed consistent patterns with those of all fish species,and there was no significant difference between all fish community and demersal fish community in terms of slope and intercept(P>0.05).The NBSS of warm temperate fish species showed a different tendency in comparison with that of all fish community(P<0.05).The size structure of fish communities in the southern waters off Shandong Peninsula was characterized by small-sized species or small-sized individuals,and the biomass size spectra were affected by the seasonal variation in fish species composition.The recruitment of seasonal migratory fish species and the young individuals each year affected the size structure of fish communities in the waters.