机构地区:[1]杭州师范大学生命与环境科学学院,杭州310036 [2]中国科学院水生生物研究所,武汉430072
出 处:《生态学报》2011年第17期4858-4865,共8页Acta Ecologica Sinica
基 金:国家自然科学基金项目(30330140;40671197);中国科学院知识创新工程重要方向项目(KZCX22YW2427);国家重点基础研究发展规划资助项目(2002CB412300)
摘 要:2006年10月—2007年10月对三峡库区香溪河太湖新银鱼、短吻间银鱼资源以及水体的主要理化因子进行调查,对太湖新银鱼、短吻间银鱼的生长特点进行了比较分析,结果表明:(1)香溪河1—3月多年平均气温为8.4℃,2月份多年平均最低10.8℃,适宜银鱼孵化的最佳温度时间为12月至翌年3月。(2)香溪河pH值全年在7.5—9.0之间变动,大多季节稳定在8.5左右,有利银鱼的繁殖生长。(3)太湖新银鱼5—6 cm规格的个体数量占优势,占总数96.2%;太湖新银鱼、短吻间银鱼的肥满度指数分别为(0.004±0.0004)g/cm3、(0.002±0.0003)g/cm3,两种银鱼的肥满度指数差异显著(P<0.001)。分析探讨了银鱼的时空分布格局、捕捞强度和渔产量对银鱼种群形成与衰退的影响。结果显示:(1)太湖新银鱼、短吻间银鱼在三峡水库湖北库区的各支流河道均有分布,沿江而上,种群规模逐渐减小,渔获量组成以太湖新银鱼为优势类群。(2)以灯光诱捕为主的扳罾网(网片规格为14.7 m×14.7 m,网目0.3 cm×0.3 cm)引入库区,使银鱼种群数量急剧下降,规格组成也发生巨大变化。2006年10月,太湖新银鱼种群主要由体长为50—60、60—70 mm的个体组成,在种群中所占的比例分别为62.3%和20.6%,大于70 mm的个体也占14.7%;2007年10月,种群主要由体长为40—50、50—60、60—70 mm的个体组成,在种群中所占的比例分别为20.2%、61.7%、15.8%,大于70 mm的个体极少见。(3)太湖新银鱼垂直活动范围在10 m以上的水层,受河岸底质的影响,山坡陡峭、浸水坡面主要由岩石构成的河岸水质清澈,银鱼数量较大。This research investigated the resources of Neosalanx taihuensis,and Hemisalanx brachyrostralis in the Xiangxi River,a tributary to the Three Gorges Reservoir.Sampling was conducted at at four sites(i.e.Xiakou,Yanguan,Qiaojiaba and Guanzhuangping) in the river during October 2006 and October 2007.At Xiakou,Yanguan and Qiaojiaba,The number of individuals of N.taihuensis and H.brachyrostralis was counted for 3 to 5 fishmen′s daily harvest every quarter,i.e.in October 2006,January,April,July,and October 2007;while at Guanzhuangping,the icefish was collected at three water depths in the column,i.e 5 m,10 m and 15 m respectively.Sampling was conducted using a lift net(area: 15 m × 15 m;mesh size: 2—3 mm) 2 or 3 times each month.During sampling,the major physical and chemical factors of the water were measured.Growth characteristics of N.taihuensis and H.brachyrostralis were analyzed.The results showed that(1) The average water temperature from January through March is 8.4℃ for many years in the Xiangxi River;The average minimum water temperature in February was 5.9℃ for years.The season with the water temperature suitable for the incubation of ice-fish was between December and March.(2) The pH of Xiangxi River ranged from 7.5 to 9.5 around the year,and is usually about 8.5,which is good for reproduction and growth of both species.(3) The contents of major nutrition varied among the sampling sites,and could basically support the growth of ice-fish.(4) Individuals of 5—6 cm standard length accounted for 96.2% of the harvest of N.taihuensis.The fullness index of N.taihuensis and H.brachyrostralis are(0.004±0.0004) g/cm3 and(0.002±0.0003) g/cm3 respectively,which was significantly different between the two species(P0.001).Spatial pattern of the populations and the impacts of fishery harvest and fishing intensity on population dynamics of both species were also discussed.(1) The N.taihuensis and H.brachyrostralis live in all the tributaries in the Three Gorges Reserv
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