基于支持向量机的西北太平洋柔鱼渔场预报模型构建

Fishing ground forecasting model of Ommastrephes bartramii based on support vector machine(SVM) in the Northwest Pacific

  • 摘要: 柔鱼(Ommastrephes bartramii)是中国在西北太平洋主要的鱿钓捕捞对象。准确预报柔鱼渔场,对减少寻鱼时间、节省油料和提高渔获产量均有积极的意义。该研究将2002年~2012年中国在西北太平洋鱿钓产量数据、渔场时空数据以及海表温度、叶绿素a浓度、表温梯度强度和叶绿素梯度强度等海洋环境因子作为训练数据,基于支持向量机(support vector machine, SVM)的方法,建立了以月为时间分辨率、0.5°×0.5°为空间分辨率的西北太平洋柔鱼渔场的预报模型。该模型以径向基函数(RBF)为核函数,利用10折交叉验证和网格选优法,确定了最优惩罚项因子和核函数参数值的组合(Cγ),分别为1.41和2.83,样本分类精度达73.6%。利用2013年7月~11月环境数据,对模型进行了精度检验,预报准确率为53.4%~60.0%,平均准确率为57.4%。研究认为,在训练数据不够充分的条件下,SVM模型可成为西北太平洋柔鱼渔场预报的一个有效手段。

     

    Abstract: Ommastrephes bartramii is one of the most important commercial fishing targets for China in the Northwest Pacific. Accurate forecast of the fishing ground helps locate the shoal, save fuel and improve yield. In the present study, historical catch log data and environmental factors including sea surface temperature (SST), chlorophyll-a concentration(Chl), SST gradient(SSTG) and Chl gradient(ChlG) in the Northwest Pacific Ocean were collected. Based on the support vector machine (SVM), squid fishing ground forecast model was established with Radial Basis Function (RBF) kernel in the monthly resolution and the spatial resolution of 0.5°×0.5°. The optimal combination of penalty parameter (C=1.41) and kernel parameter (γ=2.83) were obtained by 10-fold cross validation and grid-search when the accuracy of model reached 73.6%. A simulated accountancy test was carried out using monthly environmental data in 2013. The accuracy rate ranged from 53.4% to 60.0% with 57.4% on average. The result suggests that SVM can provide an efficient means for squid fishing ground forecast with a small training dataset in the Northwest Pacific.

     

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