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Changes in trophic flows and ecosystem properties of the Beibu Gulf ecosystem before and after the collapse of fish stocks

机译：鱼类种群崩溃前后北部湾生态系统的营养流和生态系统特性的变化

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摘要

Mass-balance models (Ecopath) of the ecosystem before and after collapse (1959-1961 and 1997-1999) offish stocks were developed with Ecopath software to compare the differences in ecosystem structure, functioning and ecosystem properties of the Beibu Gulf. The model includes 20 functional groups consisting of commercial important fish groups and other ecologically important groups in the ecosystem such as zooplankton, phytoplankton, and detritus. Results indicated that biomass and catches of the system have changed drastically between the 1960s and 1990s, especially for the high trophic levels (TL). The biomass of level V in the early 1960s was 32 times higher than that of the late 1990s, however, the biomass of level I and II in the 1990s was higher than the 1960s. Despite the higher catches in the 1990s, fishing was ecologically less expensive during the 1990s than 1960s due to small fish catches were large. Mean transfer efficiency decreased from for 10.2% in the 1960s to 9.1% in the 1990s periods. According to the summary statistics, the parameters of net system production (NPS) and total primary production to total respiration ratio were increased from 1.013 in the 1960s to 2.184 in the 1990s, however, the con-nectance index (CI), system omntvore index, Finn's cycling index and mean path length decreased from the 1960s to the 1990s. The overhead (O) was higher in the 1990s model while the ascendancy (A) decreased nearly 10% in the 1960s. The 'Keystoneness' result indicate that zooplankton was identified as keystone species in 1960s, however, the elasmobranches was keystone species in the late 1990s. The average trophic level of the fishery decreased from 3.32 in the 1960s to 2.98 in the 1990s, and exhibits classic symptoms of "fishing down the food web". All the indices of the system attributes suggests that the Beibu Gulf ecosystem in 1960s was found to be more mature than in the 1990s due to the collapse of demersal ecosystem, and the ecosystem changed from being dominated by long-lived, high trophic level groundfish dominated system toward a system with small-size and low-value species over fifty years.
机译：利用Ecopath软件开发了鱼类种群崩溃前后（1959-1961年和1997-1999年）的生态系统质量平衡模型（Ecopath），以比较北部湾的生态系统结构，功能和生态系统特性的差异。该模型包括20个功能组，其中包括商业重要鱼类群和生态系统中其他生态重要群，例如浮游动物，浮游植物和碎屑。结果表明，该系统的生物量和捕捞量在1960年代至1990年代之间发生了巨大变化，特别是对于高营养水平（TL）。 1960年代初期的V级生物量是1990年代后期的32倍，但1990年代的I和II级生物量却高于1960年代。尽管在1990年代渔获量较高，但由于小渔获量较大，因此在1990年代渔在生态上比1960年代便宜。平均转移效率从1960年代的10.2％下降到1990年代的9.1％。根据汇总统计数据，净系统产量（NPS）和总初级生产力与总呼吸比率的参数从1960年代的1.013增加到1990年代的2.184，但是，连通指数（CI），系统综合指数，从1960年代到1990年代，Finn的自行车运动指数和平均路径长度有所下降。在1990年代的模型中，间接费用（O）较高，而在1960年代，上升性（A）降低了近10％。 “基石度”结果表明，浮游动物在1960年代被确定为基石种类，但是，弹性支流在1990年代后期是基石种类。渔业的平均营养水平从1960年代的3.32下降到1990年代的2.98，并表现出“沿食物网捕鱼”的典型症状。系统属性的所有指标表明，由于水下生态系统的崩溃，1960年代的北部湾生态系统被发现比1990年代更加成熟，并且该生态系统由长寿，高营养水平的底栖鱼类为主朝着拥有五十年小规模和低价值物种的系统发展。

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  • 来源
    《Ocean & coastal management》 |2011年第8期|p.601-611|共11页
  • 作者

    Zuozhi Chen; Yongsong Qiu; Shannan Xu;

  • 作者单位

    South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China;

    South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China;

    South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China;

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