鄱阳湖区加州鲈网箱生态养殖模式的效果评估

Assessment on the efficiency of Micropterus salmoides eco-cage culture pattern in Poyang Lake District

为做好鄱阳湖区农(渔)民的"转捕为养、退田还湖"工作,发展适于湖区资源生态特点的高效渔业模式,2008—2011年在江西省都昌县鄱阳湖水域开展了加州鲈规模化网箱生态养殖试验,采用现场调查、生态监测与数据分析相结合的研究方法对养殖效益和生态经济效果进行了综合评估。结果表明,鄱阳湖的气候、生态和资源条件均适合加州鲈养殖,加州鲈年有效生长期8个月以上;2008—2011年网箱养殖的饵料系数分别为8.04、7.14、6.11和5.25,投入产出比分别是1︰1.53、1︰1.59、1︰1.77和1︰1.84,经济效益逐年递增;能量转换效率分别为0.18、0.20、0.24和0.29;生态效益也逐年提高;生态经济综合效价分别是0.36、0.42、0.58和0.70,增幅近1倍,表明该模式的经济效率、生态效率呈正相关关系,生态经济效益显著。此外,对本模式的碳汇价值和氮磷污染消减潜力的初步评估,得出2011年加州鲈网箱养殖固定的C、N、P达到7.08 t、1.18 t、0.57 t,碳汇价值评估最高可达4 250美元,相当于养殖毛利润的3.35%。加州鲈网箱生态养殖作为鄱阳湖区退田还湖的一种生态经济途径,有推广实施的价值,适宜规模的确定应以网箱养殖区小型野杂鱼类资源量的科学评估为基础。

This study introduced and analyzed Micropterus salmoides eco-cage culture pattern in Poyang Lake District for the period from 2008 to 2011.The culturing efficiency and eco-economic benefits of the pattern were assessed using an integrated approach,including on-site investigation,eco-monitoring and data analysis.The results showed that the climate,ecosystem and resources of Poyang Lake were suitable for M.salmoides culturing.The annual growth period of M.salmoides reached 8 months and more.The yearly food conversion ratios during 2008—2011 in the trial period were 8.04,7.14,6.11 and 5.25,respectively.While the input-output ratios were respectively 1：1.53,1：1.59,1：1.77 and 1：1.84,the economic benefits increased year by year for 2008—2011.The yearly energy conversion efficiencies for the period of study were respectively 0.18,0.20,0.24 and 0.29,and with increasing year-on-year eco-efficiency.The overall efficiency of eco-economy were 0.36,0.42,0.58 and 0.70,respectively,which increased by nearly one fold over the study period.It showed that a positive correlation existed between economic efficiency and eco-efficiency,with obvious eco-economic benefits.In addition,a preliminary assessment of carbon sink value and potential nitrogen and phosphorus pollution abatements showed that fixated C,N and P respectively reached 7.08 t,1.18 t and 0.57 t under M.salmoides eco-cage culture in 2011.The cash value of carbon sink was estimated at 4 250 Yuan,which was 3.35% of the gross profit from farming.M.salmoides eco-cage culture was worth popularizing as an eco-economic strategy in place of breaking dikes or opening sluices for water storage in Poyang Lake District.It was possible to determine an appropriate aquiculture scale via scientific assessment of small wild fish resources in culture zones.