基于GAM模型研究时空及环境因子对南太平洋长鳍金枪鱼渔场的影响

Effects of spatio-temporal and environmental factors on fishing grounds of albacore tuna Thunnus alalunga in the South Pacific Ocean based on generalized additive model

长鳍金枪鱼Thunnus alalung是南太平洋金枪鱼延绳钓渔业的主要捕获鱼种之一,为了开展对南太平洋长鳍金枪鱼渔场时空分布及其与海洋环境关系的研究,根据2009—2012年南太平洋长鳍金枪鱼延绳钓生产统计数据及遥感获取的海表温度(SST)、叶绿素a浓度(Chl-a)和海面高度距平(SSHA)等环境数据,利用广义可加模型(GAM)分析了长鳍金枪鱼渔场分布及与时空、环境因子的关系。结果表明:GAM模型对长鳍金枪鱼单位捕捞努力量渔获量(CPUE)总偏差解释率为11.34%,其中贡献最大的为时间(周),贡献率为6.35%;该渔场全年均可作业,5—7月CPUE值高于1—3月和10—12月,其中5月中旬—7月下旬为鱼汛盛期;长鳍金枪鱼渔场主要分布在10°S^30°S、162°E^174°E的海域范围内;中心渔场最适SST范围为26.0~29.5℃,最适Chl-a浓度范围为0.02~0.05 mg/m^3,最适SSHA范围为0~20 cm。研究表明,影响渔场的因子按重要性从大到小依次为时间(周)、纬度、SST、经度、SSHA和Chl-a。

The spatial-temporal profiles and marine environments related to fishing ground distribution were investigated in albacore tuna Thunnus alalunga,one of the main catch fisheries for longline fishery in South Pacific,based on the catch data of longline fishery from 2009 to 2012 and the environmental data including sea surface temperature（SST）,Chlorophyll-a concentration（Chl-a）,and sea surface height anomaly（SSHA） derived from remote sensing by a generalized additive model（GAM）.The results showed that the deviance of catch per unit effort（CPUE） was explained at a rate of 11.34% by the GAM,and that time（week） was the maximal contribution factor with contribution rate of 6.35%.The catching of albacore tuna was operated in the fishing grounds throughout the year,with significant seasonal change.There was higher CPUE from May to July than from January to March and from October to December.The peak fishing was observed from mid-May to later July,and the fishing grounds of albacore tuna in the South Pacific Ocean was mainly located in the water areas of 10°S-30°S and 162°E-174°E.In the central fishing ground,the suitable SST was ranged from 26.0 ℃ to 29.5 ℃,the suitable Chl-a was varied from 0.02 mg / m^3 to 0.05 mg / m3,and the appropriate SSHA was ranged from 0 cm to 20 cm.The stepwise GAM revealed that the relative importance of the six variables above in the fishing grounds of albacore tuna was followed by the order as： time（week） 〉 latitude 〉 SST 〉 longitude 〉 SSHA 〉 Chl-a concentration.