View from the hut
What effect do wind turbines have on salmon? asks Dani Moreyl
LIVING AT THE TOP OF A HILL, THE first high ground off the North Sea, for many years I enjoyed uninterrupted views across the Moray Firth. A few years ago, the vista became clogged with endless wind turbines, which, although several miles away, are still visible to the naked eye. Another windfarm a few miles behind the house means that in an unfavourable wind the persistent humming can be heard and felt even behind closed doors. It made me wonder whether these installations have any effect on salmon and sea-trout as they travel from breeding gravels in a river to feeding grounds at sea? Our hills and coastlines around the UK are dotted with turbines providing “green energy” but at what cost? Anyone living or passing in the vicinity of one will know well the vibrations can be heard from some distance.
It’s believed that salmon navigate through olfactory receptors and magnetite (tiny magnetic particles in their brains), using the earth’s magnetic field like a compass. Interestingly, human brains also contain magnetite, although we often seem to lack the same skilled navigation. Windfarm construction creates sediment, noise, vibration and drilling, but also, once operative, the cables transferring the power back to land are known to emit their own electromagnetic fields. Could this affect a fish’s senses enough to confuse them? In mitigation, cables are buried, which then causes more ecological disturbance that, alongside noise from aerodynamic blades, gearboxes and other machinery, may interrupt or even create a barrier to migration.
There have been several research projects into the ecological implications of the construction and operation of windfarms. One by the University of Maryland looked at the potential impact on established migration patterns of Atlantic salmon. The project sought to minimise the effect of offshore construction and looked at migratory timings so that building could be carried out at times when susceptible fish were not in the area. The study further analysed whether the windfarm site might actually create a new habitat where fish would stopover to feed or rest on their journey. Fish were caught and tagged with tracking devices before being released. The accumulated data showed that fish did indeed linger in the region of farms, but could this paus
