Belias Christos V, Bikas Vassilis G, Dassenakis Manos J, Scoullos Michael J
University of Athens, Department of Chemistry, Laboratory of Environmental Chemistry, Panepistimiopolis, GR-15771 Athens, Greece.
Environ Sci Pollut Res Int. 2003;10(5):287-95. doi: 10.1065/espr2003.06.159.
GOAL, SCOPE AND BACKGROUND: Over the last decade Greece has become a leading country in the EU as concerns the cage farming of seabream and seabass. A strong debate has risen, however, about the environmental impacts of aquacultures in the coastal areas. The present paper deals with this problem and it is based on measurements of physico-chemical parameters in the water column, particulate matter and sediments in the area of Astakos Gulf, a coastal embayment in western Greece where three big fish farms are currently operating.
Water samples were collected by using Hydro-Bios sampling bottles, whereas a prototype sediment trap was installed under a fish cage for the collection of particulate matter. Temperature, dissolved oxygen, pH and salinity were measured in situ using portable equipment. Nutrients were determined by standard spectrophotometric methods. Trace metals were determined by Atomic Absorption Spectrometry. Dissolved organic carbon was determined by a Shimadzu 5000A carbon analyzer, whereas organic carbon in sediments was determined titrimetrically.
No clear eutrophication incidents have been identified, although the water column near the fish farms was enriched in nutrients and organic carbon. A sludge 'blanket' covers considerable parts of the seabed and is enriched in colloidal organic carbon and trace metals (Cd, Cu, Fe and Zn) that come from unused fish food. The biodegradation of this sludge leads to the development of anoxic conditions followed by the formation of undesirable gases, precipitation or remobilization of metals and the extinction of benthic fauna.
The operation of fish farms at the coastal area of Astakos Gulf, and probably in similar Mediterranean gulfs, affects the marine environment, particularly in the vicinity of the cages. The most significant influence concerns the near-bottom water layer. The environmental impacts depend on the amount of food given to fishes, the mode of feeding, the fish density in cages, the annual production and the years of unit operation. The hydrology and the geomorphology of the area are also critical factors for its environmental quality.
The success of the fish-farming sector in the Mediterranean is accompanied by environmental and, in some extents, by social and marketing problems. These problems, derived from the rapid development of fish farming, can be solved only through an integrated management, using methods such as environmental impact assessment, risk assessment, economic evaluation, vulnerability assessments, resource accounting, cost-benefit analysis and outcome-based monitoring.
目标、范围与背景：在过去十年里，希腊在欧盟成为了海水鲷鱼和鲈鱼网箱养殖的领先国家。然而，一场关于沿海地区水产养殖对环境影响的激烈辩论已经展开。本文探讨了这一问题，其依据是对希腊西部沿海海湾阿斯塔科斯湾（Astakos Gulf）水柱、颗粒物和沉积物中的物理化学参数的测量，该地区目前有三个大型养鱼场在运营。
使用Hydro - Bios采样瓶采集水样，同时在鱼笼下方安装一个原型沉积物捕集器用于收集颗粒物。使用便携式设备现场测量温度、溶解氧、pH值和盐度。通过标准分光光度法测定营养物质。通过原子吸收光谱法测定痕量金属。使用岛津5000A碳分析仪测定溶解有机碳，沉积物中的有机碳通过滴定法测定。
尽管养鱼场附近的水柱中营养物质和有机碳含量有所增加，但尚未发现明显的富营养化事件。一层污泥“毯”覆盖了相当大一部分海床，并且富含来自未使用的鱼食的胶体有机碳和痕量金属（镉、铜、铁和锌）。这种污泥的生物降解导致缺氧条件的发展，随后形成不良气体、金属沉淀或再迁移以及底栖动物灭绝。
阿斯塔科斯湾沿海地区以及可能类似的地中海海湾的养鱼场运营会影响海洋环境，特别是在鱼笼附近。最显著的影响涉及近底层水层。环境影响取决于投喂给鱼类的食物量、投喂方式、鱼笼中的鱼密度、年产量以及单位运营年限。该地区的水文和地貌也是影响其环境质量的关键因素。
地中海养鱼业的成功伴随着环境问题，在一定程度上还伴随着社会和市场问题。这些因养鱼业快速发展而产生的问题，只有通过综合管理，采用环境影响评估、风险评估、经济评估、脆弱性评估、资源核算、成本效益分析和基于结果的监测等方法才能解决。
