调水调沙前后黄河口渔业资源结构变化

黄河口调水调沙是以人工调控的方式将淤积的泥沙送入大海,增加河床和水库主槽行洪能力的过程。根据2011―2013年调水调沙前(6月)、后(7月)在黄河口海域的渔业资源调查数据,利用相对优势度指数、方差分析以及多元统计分析等方法,研究了该海域夏季渔业资源密度、种类组成、优势种及其年际变化,并探讨调水调沙对黄河口渔业资源结构的影响。结果表明,本次调查共鉴定渔业资源生物92种,其中鱼类52种;黄河口主要优势种为矛尾虾虎鱼(Chaemrichthys stigmatias)、枪乌贼(Loligo spp.)和葛氏长臂虾(Palaemon gravieri)等,各年份优势种有所变动;夏季渔业资源量有明显年际波动,在2011—2013年呈先增加后减少的趋势,各年间差异显著;黄河口渔业资源结构在调水调沙前后有明显变化,调水调沙后渔业资源平均密度增大,且近河口区资源密度较小;CLUSTER聚类分析表明黄河口渔业资源结构年际变化最为明显,其次是调水调沙前后的变化,而断面间的差异性最低。结论认为,黄河调水调沙引起的径流量、营养盐变化可能是引起调水调沙前后渔业资源种类组成、资源量变化的重要原因。

Composition and distribution of fishery resources before and after the water and sediment discharge regulation in the Yellow River estuary

Water and sediment regulation involves artificially depositing sediments from rivers and reservoirs to the sea,thus increasing the main channel discharge capacity.Based on survey data before and after water and sediment regulation (June and July) in the Yellow River during 2011-2013,we used the index of relative importance (IRI),ANOVA,and multivariate analysis to evaluate the effect of this regulation procedure on fishery resources (species composition,distribution,and dominance) in the Yellow River estuary.We identified 92 species,including 52 fish species.Chaemrichthys stigmatias,Loligo chinensis,and Palaemon gravieri were dominant species,although their exact ranking varied across years.From 2011 to 2013,biomass first increased,then decreased,whereas fishery resources clearly changed in structure before and after water and sediment regulation.Average fishery resource density increased after water discharge and was low near the river mouth.CLUSTER analysis showed that between-year variation in community structure was the greatest,followed by variation resulting from water and sediment regulation,and finally,by variation between sampling sections.Post-regulation changes in water input and nutrient concentration of the Yellow River likely contribute to the variation in species composition and distribution in the region.