上犹江水库鲢鳙生态增殖区与禁捕区鱼类群落营养结构差异的研究

Difference in the trophic structure of fish communities in theecological-stocking area of Hypophthalwvichthys molitrix and H.nobilisand the closed-fishing area in Shangyoujiang Reservoir

为探明鲢鳙增殖对上犹江水库食物网结构的调控,2022年5月-2023年2月对上犹江水库生态增殖区(崇义段)和禁捕区(上犹段)开展渔业资源调查,依据主要消费者及饵料生物样品的碳、氮稳定同位素值(δ^(13) C、δ^(15) N),利用SIBER和MixSIAR模型分析两个区域渔获物群落营养结构差异,并初步构建食物网。结果显示:生态增殖区和禁捕区的主要渔获物δ^(13) C值范围分别为-28.40‰~-22.13‰和-32.03‰~-17.36‰;δ^(15) N值范围分别为7.83‰~14.68‰和6.34‰~16.41‰;营养级范围分别为1.28~4.25和1.97~3.74,其中,生态增殖区和禁捕区营养级最高的鱼类均为肉食性鱼类鳡,营养级最低的鱼类分别为细鳞斜颌鲴和黄尾鲴;与禁捕区相比,生态增殖区鱼类摄食的食物资源更丰富、所占的生态位更宽,但群落营养结构各项指标,包括NR、CR、TA、CD、NND和SDNND均低于禁捕区。湿地植物为生态增殖区的主要碳源,而浮游植物为禁捕区的主要碳源。本研究揭示了禁捕区和生态增殖区鱼类群落营养结构的差异,为后续湖泊水库等大水面生态放养与生态修复提供理论依据。

Shangyoujiang Reservoir is located between Chongyi County and Shangyou County in Jiangxi Province of China.It is one of several large reservoirs in Jiangxi Province.The Shangyou Section of Shangyoujiang Reservoir is a national aquatic germplasm conservation zone,and the Chongyi section is an essential large surface fishing base for breeding,stocking and adult fish reproduction of silver carp and bighead carp.Comparing the differences in aquatic food networks in the two regions is significant for their subsequent ecological stocking and the management of no-take lakes and reservoirs.The fishery resources in the ecological-stocking area(Chongyi section)and closed-fishing area(Shangyou section)of Shangyoujiang Reservoir were investigated from May 2022 to February 2023 to investigate the regulation of the growth of Hypophthalwvichthys molitrix and H.nobilis on the food web structure of Shangyoujiang Reservoir.SIBER and SIAR models were used to analyze the trophic structure differences of the two fish communities and initially construct the aquatic food web.The results showed that theδ^(13) C values of fish in the ecological-stocking area and the closed-fishing area ranged from-28.40‰to 22.13‰and-32.03‰to-17.36‰,respectively.Theδ^(15) N values ranged from 7.83‰to 14.68‰and 6.34‰to 16.41‰,respectively.The trophic levels ranged from 1.28~4.25 and 1.97~3.74,respectively.In both water areas,the trophic level of carnivorous Elopichthys bambusa was highest.Plagiognathops microlepis and Xenocypris davidi trophic levels were the lowest in the ecological-stocking and closed-fishing areas,respectively.Compared with the closed-fishing area,the fish in the ecological-stocking area had more abundant food resources and occupied a broader ecological niche.However,the indices of community nutrition structure,including NR,CR,TA,CD,NND,and SDNND,were lower than those in the closed-fishing area.Wetland plants are the main carbon sources in the ecological stocking area,and phytoplankton are the main carbon sources in the closed-fishing area.This study revealed the difference of the trophic structure of fish communities between the closed-fishing areas and the ecological-stocking area,which provide a theoretical basis for ecological-stocking and ecological restoration in large water surfaces such as lakes and reservoirs.