Given the ambitious plans for offshore wind, it is important to know what effects wind turbines have on the ecology. For example, little was known about the impact of underwater noise from wind farms, especially during construction, on the so-called pelagic fish communities. An interdisciplinary research project to provide more insight into this has now been completed and offers surprising insights.
Pelagic fish range from small inshore prey fish, such as herring and sardines, to large oceanic predatory fish, such as tuna, sailfish and barracuda. Most pelagic fish are agile swimmers, able to cover long distances. They often swim in schools in the open sea, some distance from the coast and the seabed. These fish communities play a key role in the food chain and are of great commercial value.
Research
The APELAFICO research project, funded by the Netherlands Scientific Organization (NWO) and Rijkswaterstaat, was carried out by a number of scientists from Leiden University under the leadership of professor of ecology Hans Slabbekoorn.
The aim of the research is to determine the effects of underwater noise caused by the construction and operation of offshore wind farms on pelagic fish.
The research used sonar images to determine the presence and behavior of pelagic fish around operating wind turbines and in a danger zone when driving piles. The reactions of fish to certain sounds to scare the fish away from the danger zone were also investigated. The research was carried out on location at the Hollandse Kust Zuid and -Noord plots during the construction phase.
Results
The first results are surprising. There are clear results in the basin and at sea: in the basin there is mainly a change in swimming direction and at sea we see little change in swimming depth or horizontal displacement. Surprisingly, pelagic fish schools hardly moved, even in the vicinity of piling activities.
The findings do not mean that pelagic fish would not be disturbed by piling noise or by operational wind farms, but no indications were found that indicate disturbance.
More results to follow. And data on fish and porpoise presence during the operational phase of wind farms is being further developed.
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