浙江中北部近海三疣梭子蟹资源时空分布特征及其与环境因子的关系

Spatial-Temporal Distribution of Portunus trituberculatus Resources and Its Relationship with Environmental Factors in the Coastal Waters of North-Central Zhejiang Province

三疣梭子蟹是东海重要的经济蟹类之一,为了解其资源时空分布规律,根据2015—2018年4月(春季)和11月(秋季)浙江中北部近海底拖网渔业资源调查数据,利用两阶段广义加性模型(Two-stage GAM),分析其资源时空分布与水深、底温、底盐、溶解氧和叶绿素a浓度等海洋环境因子之间的关系。结果表明:三疣梭子蟹空间分布具有明显的年际和季节变化,2016年三疣梭子蟹的丰度最高,2017年丰度最低,秋季丰度明显高于春季,春季三疣梭子蟹主要分布在122°30′E以西的近岸浅水区,秋季分布范围扩展至122°30′E以东的深水区。水深和底温是影响三疣梭子蟹时空分布的主要环境因子,三疣梭子蟹春秋两季的丰度均随水深增大而减小,随底温增大而增大,其最适水深为3~30 m,最适底温为19~22℃。该研究阐明浙江中北部近海三疣梭子蟹资源分布状况,为实施科学的捕捞和管理策略提供基础资料。

Portunus trituberculatus is one of the most important economic crabs in the East China Sea.In order to understand its spatial-temporal distribution and the relationship with environmental factors,a Two-stage generalized additive model(Two-stage GAM)was developed,based on the survey data of offshore bottom trawl fishery resources in the north-central sea of Zhejiang province in April(spring)and November(autumn)from 2015 to 2018.The results showed that the distribution of P.trituberculatus had obvious inter-annual and seasonal variations,with the highest abundance in 2016 and the lowest abundance in 2017.The abundance is significantly higher in autumn than spring.Water depth and sea bottom temperature are the main environmental factors affecting the spatial-temporal distribution of P.trituberculatus.In addition,P.trituberculatus are mainly distributed in the coastal waters to the west of 122°E.The optimum environmental factors are the water depth of 3-30 m and the sea bottom temperature of 19-22℃.The abundance decreased with the increase of water depth.The abundance rised greatly with the increase of the sea bottom temperature.This study is aiming to understand the distribution of P.trituberculatus,to provide basic information for the implementation of scientific fishing and management strategies.