基于集成学习的南太平洋长鳍金枪鱼渔场预报模型研究

Research on fishing grounds forecasting models of albacore tuna based on ensemble learning in South Pacific

  • 摘要: 文章利用2008—2015年南太平洋长鳍金枪鱼 (Thunnus alalunga) 延绳钓渔业数据,结合11个环境指标 (海表温度、叶绿素a (Chl-a)浓度、海表温度距平、叶绿素距平、海表温度梯度、叶绿素梯度、海平面异常以及渔区格网对应的前后各1个月海表温度和叶绿素值) 和3个时空指标 (月、经度和纬度),并基于6种集成学习模型,以月为时间分辨率、0.5°×0.5°为空间分辨率,开展了南太平洋长鳍金枪鱼渔场模型构建和预报研究。模型通过10折交叉验证和网格搜索思想确定最佳参数,采用的随机森林、Bagging决策树、C5.0决策树、梯度提升决策树、AdaBoost、Stacking集成模型分别取得了75.52%、73.87%、72.99%、71.14%、71.33%、75.84%的分类准确率。经对比,Stacking集成模型准确率最高。利用2015年环境数据进行预报精度检验,预报总体准确率为63.86%~82.14%,平均70.99%;高单位捕捞努力量渔获量 (Catch per unit effort, CPUE) 渔区预报准确率为62.71%~97.85%,平均78.76%。结果表明Stacking集成模型对南太平洋长鳍金枪鱼渔场的预报具有较好的效果及可行性。

     

    Abstract: According to the data of longline fishing of Thunnus alalunga in the South Pacific Ocean from 2008 to 2015, we investigated  11 environmental indicators (sea surface temperature, chlorophyll a concentration, sea surface temperature anomaly, chlorophyll anomaly, sea surface temperature gradient, chlorophyll gradient, sea level anomaly, and sea surface temperature and chlorophyll values one month before and after the corresponding fishing area grid) and three spatio-temporal indicators (month, longitude and latitude).  Besides, based on six integrated learning models, taking month as time resolution and 0.5°×0.5° as space resolution, we carried out the model construction and prediction of T. alalunga fishery in the South Pacific. The optimal parameters of the model are determined by 10 fold cross validation and grid search. The accurary rates of RF (Random forest), Treebag, C5.0 decision tree, GBDT (Gradient boosting decision tree), AdaBoost (Adaptive boosting) and Stacking integration model were 75.52%, 73.87%, 72.99%, 71.14%, 71.33% and 75.84 %, respectively. The Stacking integration model had the highest accuracy. We used 2015 environmental data to test the forecast accuracy, and find that the overall forecast accuracy was 63.86%−82.14%, with an average of 70.99%; the forecast accuracy of catch per unit effort (CPUE) fishing area was 62.71%−97.85%, with an average of 78.76%. The results show that the Stacking integration model has a good effect and feasibility on the prediction of T. alalunga fishery in the South Pacific.

     

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