长江下游靖江段沿岸贝氏■渔获量的时间格局及ARIMA模型预测

Temporal pattern of Hemiculter bleekeri catches at Jingjiang Section of the Yangtze River and catch forecast by using ARIMA model

长江靖江段是长江下游和河口渔业资源养护的重要地区,贝氏[歺又鱼]（Hemiculter bleekeri）在维系这一水域鱼类物种多样性和保持生态平衡方面起着重要作用。2002-2006年,在靖江沿岸滩涂湿地利用一部长40m、高1.8m、网目长度1.86cm的定置张网采集142份渔获物样本,共获鱼类46142尾,其中贝氏[歺又鱼]20966尾,占总尾数的45.44%;平均每网次渔获数量148尾,最高达855尾,最低为11尾。在所有244595.36g鱼类渔获物中,贝氏[歺又鱼]有70176.69g,占总渔获物质量的28.69%;平均每网次渔获质量497.71g,最高2538.00g,最低32.59g。分析表明,贝氏[歺又鱼]月渔获质量呈非平稳的随机过程。用SPSSV13.0软件对2002年1月-2006年12月的月渔获质量数据进行ARIMA建模拟合,建立了方程为（1-B^12）lnyt=（1-0.801B^12）et-0.133的ARIMA（0,0,0）（0,1,1）12（含常数）的预测模型。该模型对2003-2006年的拟合精度在91.82%-96.48%之间,对2007年逐月预测的相对精度为81.30%-99.69%,年预测精度达93.73%,可有效预测贝氏的渔获量。

Jingjiang section, located between the lower reaches and estuary of the Yangtze River, is an important area for fishery resource conservation. Hemiculter bleekeri also plays an important role in maintaining species diversity and keeping the balance of ecology. From 2002 to 2006, there were 46 142 fish belonging to 142 batches of fish samples captured by a stow net of 40 m in length, 1.8 m in height and mesh size 1.86 cm at Jingjiang coastal wetland. The number of H. bleekeri was 20 966, accounting for 45.44% of the total. The average catch number of H. bleekeri per haul was 148 while the maximum was 885 and the minimum was 11. Among the total 244 595.36g of fish catch, H. bleekeri was 70 176.69g,occupying 28.69%. The average catch weight of H. bleekeri per haul was 497.71 g while the maximum was 2 538 g and the minimum was 32.59 g. Analysis indicated that monthly fish catch weight of H. bleekeri presented a Nonstationary Random Process. SPSS V13.0 software was used to construct the ARIMA model based on monthly fish catch data from January 2002 to December 2006 and ARIMA（0,0,0）（0,1,1）12 model included an equation of（ 1-B^12） lnyt=（1-0.801B^12）et-0.133. The fitting precision of ARIMA model was 91.82%-96.48% from 2003 to 2006. Relative precision of the forecasting to monthly data in 2007 was 81.30%-99.69% while the result for 2007 was 93.73%, which could be well used to forecast the fish catch of H. bleekeri at Jingjiang section of the Yangtze River.