瓯江口凤鲚鱼卵、仔稚鱼的时空分布及其与环境因子关系

SPATIOTEMPORAL DISTRIBUTION OF EGGS AND LARVAE OF COILIA MYSTUS AND ITS RELATIONSHIP WITH ENVIRONMENTAL FACTORS ALONG OUJIANG ESTUARY

  • 摘要: 为了解凤鲚(Coilia mystus)早期群体在瓯江口的时空分布及其影响因素, 研究根据瓯江口渔业资源调查数据, 利用两阶段广义加性模型(Two-stage GAM)分析影响凤鲚鱼卵仔稚鱼分布的环境因子。采用交叉验证评价模型的预测性能, 对2020年5—7月的凤鲚鱼卵、仔稚鱼出现率及资源量进行预测。结果表明: 5—7月是瓯江口凤鲚的主要繁殖期, 鱼卵主要分布在瓯江上游七都岛附近低盐水域, 仔稚鱼在瓯江水域均有分布, 瓯江下游灵昆岛近岸水域仔稚鱼的相对资源丰度高于瓯江上游。GAM模型分析表温、表盐是影响凤鲚早期群体分布的主要环境因子, 表盐对鱼卵的分布具有极显著影响(P<0.01), 适宜表盐在1以下, 适宜表温在24—26℃; 仔稚鱼对水温、盐度的适宜度宽于鱼卵, 表温对仔稚鱼的分布具有显著影响(P<0.05), 适宜表温为22—27℃, 适宜表盐为5—13。交叉验证分析认为模型对鱼卵的预测性能(AUC均值0.83)优于仔稚鱼(AUC均值0.71)。2020年预测结果显示, 凤鲚鱼卵的适宜栖息环境较窄, 主要集中在江心屿上游及灵昆岛下游附近水域, 仔稚鱼主要栖息在江心屿至灵昆岛水域。瓯江口作为凤鲚的主要栖息场所之一, 掌握凤鲚早期群体在瓯江口的分布特征及与环境因子间的关系, 能够为其产卵场栖息地的保护和资源养护管理提供科学依据。

     

    Abstract: In order to understand the temporal and spatial distribution of Coilia mystus early population in Oujiang Estuary and its influencing factors, this study used the area under the receiver operating characteristic curve (AUC) and linear regression to evaluate the predictive performance of the model. Based on the survey data of fishery resources in Oujiang Estuary, a Two-stage generalized additive model (Two-stage GAM) was used to analyze the environmental factors affecting the distribution of Coilia mystus eggs and larvae. The results showed that the main breeding period of Coilia mystus in the Oujiang Estuary was from May to July, and that temperature and salinity of surface water were the main environmental factors affecting the early population of Coilia mystus. Surface water salinity has an extremely significant effect on the distribution of eggs (P<0.01) with the suitable surface water salinity below 1. The suitable surface water temperature of eggs ranged from 24℃ to 26℃, and it has a significant effect on the distribution of larvae (P<0.05). The suitable surface water temperature of larvae ranged from 22℃ to 27℃, and the suitable surface water salinity of larvae ranged from 5 to 13. The results of cross validation showed that the prediction performance of the model for eggs was better than that of larvae. The forecast results showed that the suitable habitat for Coilia mystus eggs was relatively narrow, mainly concentrated in the waters near the upper reaches of Jiangxinyu and the lower reaches of Lingkun Island. Coilia mystus larvae mainly inhabited in the waters of Jiangxinyu to Lingkun Island. Oujiang Estuary is one of the main habitats of Coilia mystus in China, grasping the distribution characteristics of early colony of Coilia mystus in Oujiang Estuary and its relationship with environmental factors is significantly important. The results provide a scientific basis for the selection and planning of spawning ground protection area and resources management.

     

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