Aggregation, production and spillover: the cumulative effect of man-made offshore structures on fish

在世纪后半叶，超过1300个人造结构（MMS）被安装在北海的近海海洋环境中用于石油和天然气工业，并且现在正在安装许多其他结构以获得近海可再生能源。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，在所谓的“从钻井平台到珊瑚礁”方案中成功地加强渔业。在欧洲，情况正好相反：关于北海的国际条例（即保护东北大西洋海洋环境公约第98/3号决定）要求彻底拆除废弃的海上设施。在北海，众所周知，MMS和石油和天然气MMS的鱼类聚集区有500米的渔业禁区。所以这些结构就像是小型的海洋保护区。在这种规模下，受保护的总面积相对于北海商业鱼类种群所占的面积来说非常小。然而，也有证据表明，鱼群聚集的范围远远超出了禁区，这要么是由于鱼群向MMS聚集，要么是由于生产力和保护的提高导致鱼群溢出到邻近地区。“溢出效应”是海洋保护区的一个众所周知的好处，但尚未就北海的MMS进行研究。如果这种溢出是显着的，那么MMS的面积影响可能会大于迄今assumption. There，我们使用一个无人驾驶的水面车辆配备了最先进的高分辨率声学测量技术，以评估北海MMS的鱼类聚集和溢出效应的规模。从调查的数据被用来参数化一个高空间分辨率的鱼类动态和运动模型，我们将使用测试假设的整个北海规模的网络结构的影响，包括在何种程度上，他们所产生的提高生产力或保护捕鱼提供接近硬基板，和北海规模的后果，他们的删除。 我们的研究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会首席执行官在议会委员会中所说，这可能会导致“三赢”，“......为纳税人节省了大量资金，为运营商节省了大量资金。保留钻机和其他结构周围这些有时生物多样性很高的区域，可能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."