The names Alpha Ventus and Sheringham Shoal probably don’t mean that much to you. These two places are active wind-farms, both up and running now for a several years in the North Sea. Alpha Ventus, Germany’s first offshore wind-farm, is located just north of Borkum whilst Sheringham Shoal lies further west, off the east coast of England. Wind-farms are beneficial to people, providing renewable energy but it seems that humans aren’t the only critters to benefit from their installation.
Deborah Russell from the University of St Andrews and her fellow collaborators tagged a number of gray seals (Halichoerus grypu) and harbour seals (Phoca vitulina) around the UK and the Dutch North Sea coastlines with GPS/GSM tracking devices. These are rather nifty little devices that allow us to discover where these charismatic critters have been going to. Tagging seals with these devices isn’t a easy task. The researchers first had to catch the seals, which they did using hand or seine nets, and then attach the devices to the seal’s fur, on the back of their neck. The devices are attached with an adhesive, so they do eventually come off without harming the animal.
Off the tagged seals went, doing what seals do, and the tracking devices did what tracking devices do. Time for some data analysis. Using some modelling techniques, the researchers categorised the seals behaviour into some fairly broad activity groups: resting (hauling out onto land), foraging (feeding), and finally travelling. To the researcher’s surprise, a small group of the seals from both the UK and Netherlands headed out for the wind-farms – and stayed out there for a while too before heading off to other locations. The data suggests that the seals were likely foraging around the wind turbines, which may be acting somewhat like an artificial reef. It’s not clear if the wind-farms are providing good habitat to allow the seal’s prey to increase in those areas, or simply concentrating the prey around the turbines (many marine critters like to hang out near something physical). Either way, wind-farms do seem to be a good place for this small group of seals to get their supper.
The short Correspondence piece was published in the journal Current Biology and is open access. I highly recommend having a read of it yourself, and checking out a video showing the movements of four trips one harbour seal made to Sheringham Shoal. You can find it here http://dx.doi.org/10.1016/j.cub.2014.06.033
Image: Three seals on the Isle of Bute, Scotland. Credit Paddy Patterson/Flickr (CC BY 2.0)