基于栖息地适应性指数的长江口刀鲚时空分布特征

Temporal-spatial distribution of Coilia nasus in the Yangtze River Estuary based on habitat suitability index

刀鲚是长江水域重要的洄游型鱼类,现已成为国家级重点保护资源。为研究长江口刀鲚的时空分布特征,根据2012—2014年长江口中华鲟自然保护区的渔业资源调查采样数据,分析长江口刀鲚相对资源密度(RAI)与水深,水温,盐度之间的关系,并建立栖息地适应性指数(HSI)模型。结果表明:长江口刀鲚春、冬两季的RAI较高,并主要分布在南支水域附近;刀鲚种群在长江口多栖息于水深10 m以下,盐度范围为0.0~1.0的中上层水域;春季水温与适应性指数(SI)之间变化平缓,夏、秋两季SI最大值分别出现在22.5℃和28.5℃,冬季集中分布在15℃附近水域;回归分析表明,使用几何平均法能够更好地反映出长江口刀鲚的时空分布特征。研究分析了不同季节环境因子对刀鲚分布的影响,依据HSI模型讨论了刀鲚的时空分布,并对选用的HSI模型进行评价,为保护长江口刀鲚种群并修复长江口的生态系统提供参考依据。

Coilia nasus is an important migration type species in the Yangtze River,and has now become a national key protection resource. In order to investigate the temporal-spatial distribution of Coilia nasus in the Yangtze River estuary,according to the survey data of the fishery resources investigation in Shanghai Yangtze estuarine nature during year 2012-2014,we analyzed the relationship between relative abundance index（RAI） and water depth,water temperature and salinity in the Yangtze River estuary,meanwhile established habitat Suitability Index（HSI） model. The results show that the RAI of spring and winter was higher,and was mainly distributed near southern branch of the Yangtze estuary. The population of Coilia nasus habitat in the pelagic area where water depth below 10 m,salinity range of 0-1. 0. There is a gentle change between Tem and Suitability Index（SI） in spring,and the maximum value of SI in summer and autumn appeared at22. 5 ℃ and 28. 5 ℃ respectively,in winter the population had concentrated distribution with the temperature about 15 ℃. Regression analysis shows that using the geometric mean method can reflect the temporal-spatial distribution in the Yangtze River estuary better. We analyzed that the influence of different seasons and different environmental factors on the distribution of Coilia nasus,based on HSI model we discussed the temporal-spatial distribution of Coilia nasus,also evaluated the selection of HSI model. Aimed at providing some references for protecting Coilia nasus population and then rehabilitating the Yangtze estuary ecosystem.