| 桑沟湾养殖生态系统健康综合评价 |
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| 作者姓名： | 傅明珠 蒲新明 王宗灵 刘新杰 |
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| 基金项目： | 我国近海海洋综合调查与评价专项课题(908-02-04-07);海洋公益性行业科研专项经费项目(200805069);海洋公益性行业科研专项经费项目(2013418043) |
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| 摘 要： | 桑沟湾是我国北方以筏式养殖利用为主的典型海湾,来自养殖的压力对海湾生态系统和养殖自身的健康发展产生了影响.利用《海洋养殖生态系统健康综合评价:方法与模式》建立的方法,对桑沟湾这一养殖生态系统的健康进行了综合评价.结果表明:桑沟湾养殖生态系统受到中等程度的压力,主要来自较高的养殖密度、较大的养殖面积和陆源营养盐的输入;生态系统状态等级为较好,其中水交换、水体环境和底质环境均为较好;自然生物群落状态为中等;生态系统响应中的养殖病害问题和养殖产品质量问题为中等.总体评价,桑沟湾养殖生态系统健康勉强达到较好水平,控制养殖密度和规模等措施是改善桑沟湾生态系统健康的必要途径.
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| 关 键 词： | 桑沟湾 生态系统健康评价 变化趋势 |
Integrated assessment of mariculture ecosystem health in Sanggou Bay |
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| Authors: | FU Mingzhu PU Xinming WANG Zongling and LIU Xinjie |
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| Abstract: | Sanggou Bay (122°24''-122°35''E, 37°01''-37°09''N) is a semi-enclosed bay on the north-east coast of Shandong Peninsula and is connected to the Yellow Sea in the west. It has a total area of 133.33 km2 and mean depth of 8 m. Due to its good natural environmental conditions, such as flat seafloor and high primary productivity, the bay has been used for aquaculture for over 40 years and has become the most important mariculture base in northern China. The main culture species have been seaweed and shellfish, including scallops, oysters and mussels, with an annual production of over 50,000 tonnes. Sanggou Bay has special aquaculture spatial layout with the distribution of shellfish, shellfish+kelp and kelp, respectively, from the bottom to the mouth.In order to pursue high productivity, Sanggou Bay has experienced a rapid growth in aquaculture during the past 20 years, in terms of an increase in rearing density and expansion of culture area. Pressure from the larger-scale and intensive aquaculture is believed to have impacted on the ecosystem health and sustainability of mariculture. For example, the kelp has begun to rot just before harvesting, the size of scallops has decreased and their mortality during the summer has increased. A number of studies on the ecological environment of Sanggou Bay have been carried out, including the seawater nutrient level and trophic status, the long-term changes in phytoplankton abundance and diversity, the influence of shellfish cultivation on the hydrodynamic conditions, and the pelagic and benthic ecosystems. No study on the health status of the overall ecosystem has been reported so far.In the present paper, an integrated framework developed recently was employed to assess ecosystem health in Sanggou Bay. The framework and method were developed through an analytic hierarchical process and include 25 indicators. The results showed that (i) the pressure on ecosystem health was "moderate", mainly coming from large-scale and intensive mariculture and nutrient input, especially phosphorus, from land sources. The degree of aquaculture self-pollution is not high due to nutrient absorption by kelp; (ii) the ecosystem was in a "good" state, due to "good" water exchange and quality, "good" sediment quality and a "moderate" biological community. The large-scale aquaculture did not impact the pelagic and benthic ecosystem significantly, but the natural habitat was moderately disturbed due to the important area occupied by aquaculture; (iii) the ecosystem response was "moderate" in terms of disease and seafood quality issues, and the occurrence of harmful algal blooms and alien species invasion was not serious; (iv) variations in the long-term data showed that the scale of aquaculture had expanded significantly since 1990, and that the kelp was consistently the major part of the aquaculture industry, significantly reducing the shellfish self-pollution level. The concentration of dissolved inorganic nitrogen and the N/P ratio had increased significantly, with the potential for eutrophication. The overall ecosystem health index score was slightly higher than the lower threshold for the "good" level. Controlling the density and scale of mariculture is suggested to improve the health of the Sanggou Bay mariculture ecosystem. |
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| Keywords: | Sanggou Bay ecosystem health assessment long-term variation |
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