Man-made structures may act like artificial reefs sheltering potential prey. It remains undecided as to whether environmental effects will be helpful or harmful.
According to new research, offshore wind farms may become seal hunting grounds. Although the long-term environmental impact remains in question. Located offshore, wind farms are banks of wind turbines that harness the wind's energy to produce electricity.
Taking advantage of powerful coastal winds, they can generate considerable amounts of power in a renewable manner. For example, Denmark currently gets about 30 percent of its electricity from wind power.
To learn more about the potential environmental impacts of these wind turbines, scientists tagged harbour and grey seals on the British and Dutch coasts in the North Sea. Each tag was glued onto the fur on the back of a seal's neck and carried a GPS tracking device to monitor that seal's every movement.
Upon analyzing the data, researchers discovered three harbour seals moved "in a very striking grid pattern," said lead study author Deborah Russell, marine ecologist at the University of St. Andrews in Scotland. The three seals were part of a group of 11 seals that swam within two active offshore wind farms: Alpha Ventus off the coast of Germany, and Sheringham Shoal off the east coast of England.
Straight lines between wind mills
The grid patterns of the seals' movements indicated the animals swam in straight lines between wind turbines. "We could actually pinpoint where the wind turbines were by looking at the paths the seals traveled,” said Russell.
The scientists also observed both grey and harbour seals visiting offshore oil and gas pipelines. These man-made structures may act like artificial reefs sheltering potential prey. "This is the first time marine mammals have shown use of these artificial structures for foraging," Russell said.
As wind farm numbers expand, it remains undecided what the environmental impact of will be for seals and their prey. If the farms increase the prey available for seals, "then the effects may be positive overall," Russell said. "However, if they are simply concentrating existing prey and making them vulnerable to predation to animals such as seals, that could deplete the populations of those prey."
This is the first time marine mammals have shown use of these artificial structures for foraging."
—Deborah Russell, marine ecologist at Scotland’s University of St. Andrews.