Aggregation, production and spillover: the cumulative impact of man-made structures on fish.

20世纪后半叶，在北海近海海洋环境中为石油和天然气工业安装了1300多个人造结构物(MMS)，现在正在安装许多其他结构物以获取海上可再生能源。越来越多的证据表明，这种结构具有生态效益，尤其是对海洋鱼类。在美利坚合众国，MMS(特别是石油钻井平台)被用作珊瑚礁，以在所谓的钻井平台到珊瑚礁方案中成功地加强渔业。欧洲的情况正好相反：管理北海的国际条例(即奥斯巴第98/3号决定)要求完全拆除废弃的近海设施。在北海，众所周知，在MMS和石油和天然气MMS聚集的鱼类有500米的渔业禁区。因此，这些建筑物充当了小型海洋保护区的角色。在这种规模下，与北海商业鱼类种群占据的面积相比，保护的总面积非常小。然而，也有证据表明，鱼的聚集远远超出了禁区，这要么是向MMS聚集的结果，要么是生产力和保护的增强导致鱼类溢出到邻近地区。“溢出效应”是众所周知的海洋保护区的好处，但还没有被研究与北海的MMS有关。如果这种溢出是显著的，那么MMS的面积影响可能比迄今认为的更大。在这里，我们使用配备最先进的高分辨率声学测量技术的无人水面航行器来评估北海MMS鱼类聚集的规模和溢出效应。来自调查的数据被用来对鱼类动态和运动的高空间分辨率模型进行参数化，我们将使用关于结构网络的整个北海尺度效应的检验假设，包括它们产生于提高生产力或由于靠近坚硬底质而免受捕捞的程度，以及它们被移除的北海尺度后果。我们的结果将被北海的石油和天然气运营商使用，其中一家是我们项目的合作伙伴，为他们的累积影响评估提供信息。这将为减损移除提供证据，正如苏格兰野生动物信托基金的首席执行官在议会委员会中所说，这可能会导致“三赢”，“……为纳税人节省大量资金，为运营商节省大量资金。保留钻井平台和其他结构周围这些有时高度生物多样性的区域可能会对环境产生净积极影响。”

In the latter half of the 20th century, over 1300 man-made structures (MMS) were installed in the offshore marine environment of the North Sea for the oil and gas industry, and many others are now being installed to obtain offshore renewable energy. There is mounting evidence for the ecological benefits of such structures, not least for marine fish. In the United States of America, MMS (particularly oil rigs) are used as reefs to successfully enhance fisheries in the so-called, Rig to Reefs programme. In Europe the opposite occurs: international regulations governing the North Sea (i.e. OSPAR Decision 98/3) require the complete removal of disused offshore installations. In the North Sea it is well known that fish aggregate at MMS and oil and gas MMS have 500 m fishery exclusion zones. So the structures act as small marine protected areas. At this scale, the total area protected is very small relative to the area occupied by commercial fish stocks in the North Sea. However, there is also evidence that aggregations of fish extend well beyond the exclusion zone, which is either a result of aggregation towards the MMS or enhanced productivity and protection resulting in fish spilling over into the adjacent area. The "spillover effect" is a well-known benefit of marine protected areas but has not been studied in relation to MMS in the North Sea. If this spillover is significant, then the area influence of MMS could be greater than hitherto assumed.Here, we use an unmanned surface vehicle equipped with state of the art high resolution acoustic surveying techniques to evaluate the scale of aggregation and spillover effect of fish from North Sea MMS. Data from the surveys are used to parameterise a high spatial resolution model of fish dynamics and movements which we will use test hypotheses about the whole North Sea scale effects of networks of structures, including the extent to which they arise from enhanced productivity or the protection from fishing afforded by proximity to hard substrate, and the North Sea scale consequences of their removal.. Our results will be used by oil and gas operators in the North Sea, one of which is a partner in our project, to inform their cumulative impact assessments. This will provide evidence for derogating removal, which as stated by the CEO of the Scottish Wildlife Trust, in a parliamentary committee, could result in "a triple win", with "...substantial savings to the taxpayer and substantial savings to the operator. There could be a net positive effect on the environment in the retention of these sometimes highly biodiverse areas around rigs and other structures."