Why Seals Might Love Having More Wind Farms
New research reveals that off-shore wind farms are particularly useful for seals as they appear to act like artificial reefs, drawing in large groups of fish.
The study, carried out by researchers at St Andrews University in Scotland and published this month in the journal Current Biology, saw scientists track a group of seals in the North Sea using GPS devices. The purpose of the study was to look at whether man-made changes to the structural ocean environment are affecting marine predator behavior.
To explain that, the scientists highlight that whenever we make changes to the landscape for the purposes of building or reshaping a particular location, those changes can affect local wildlife. For instance, and for a not particularly green example, by creating a landfill, we may attract a variety of animals that can utilize the rubbish we have thrown out. Quite often, the concentrations of these foraging animals can affect change in predator animals, too. They will be drawn to these areas in order to hunt for those animals further down the food chain who are using the area for their own food and habitat needs.
This kind of change as a result of our reshaping the environment is well documented on-land, but until now the effect has not been tracked in marine environments.
Looking at the tracking data from two groups of harbor and grey seals, which are good candidates for this kind of research because they are apex predators, which have no known predators above them affecting their behavior, the scientists found that a number of seals from each group regularly visited off-shore wind farms, the Alpha Ventus farm off the German coast, and the Sheringham Shoal farm close to southeast England.
When looking at the tracking data, the researchers noticed that rather than just swimming through the wind farms, the seals appeared to be hunting. They could tell this by the fact that a number of the seals adopted grid-like movements around particular turbines, methodically searching for fish in patterns that have previously been observed as classic hunting behavior. This wasn’t a one-off either, with a number of seals repeatedly returning to the wind farms and displaying the same behavior. The seals were also shown to do the same around sub-sea pipelines, with the seals following along the line of the area up to ten times a day.
Lead researcher Deborah Russell says that this is quite new behavior that is only displayed by a few seals right now, but that could change: “I was shocked when I first saw the stunning grid pattern of a seal track around Sheringham Shoal. You could see that the individual appeared to travel in straight lines between turbines, as if he was checking them out for potential prey and then stopping to forage at certain ones. Only a small proportion of our study seals utilized [wind farms] or pipelines. At present these structures cover a small proportion of the extent of the at-sea distribution of seals. As wind farms become more extensive, many more seals will likely be affected.”
It’s unclear whether our changes to the habitat have led to greater stocks of prey, or whether by altering the landscape the fish have become concentrated in these areas and more vulnerable. More studies will be needed to determine that, but the researchers say these insights are important because they help to add to the debate over wind farms.
While renewable wind power energy is a valuable resource, arguments against it have included that off-shore wind farms may damage the delicate ecological balance of marine habitats. Those concerns aren’t necessarily overblown as scientists aren’t sure how long marine habitats need to recover from wind farm construction. There are also concerns about the damage to local wildlife, but as this latest research shows, it’s not an easy thing to gauge.
While, for instance, wind farm construction may damage the hearing of some marine species such as whales and sharks, and may displace native populations, other research has shown that, by creating artificial reefs, wind farms actually could give safe environments for certain fish and in turn allow them to increase their numbers.
As this shows, research like tracking seals with GPS is important because it helps us to more precisely assess our impact and to know whether we’re doing more harm than good. Particularly here, we need to know whether seals, as apex predators, will hunt the fish until their numbers collapse. This kind of ecology trap has to be avoided for both the fish and the seals, and so continued observations will give us the answer to this, and possible ways of solving any problems that might show up in these observations.
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