- 13 Jan 2020
Marine Scotland Science (MSS) has contributed substantial resource to the issue of identifying any negative effects of development of marine renewable energy on salmonid and other freshwater-marine migratory fishes within research conducted jointly with the Renewables Programme. Evaluation of the effects of generation of marine and offshore renewable energy (MORE) on Atlantic salmon and other freshwater fish that migrate to and from sea (diadromous fish) has included a series of processes. There has been review of information on migration (Malcolm et al., 2010) (below) and effects of noise and electromagnetic fields (EMFs) (Gill & Bartlett, 2010; Gill et al., 2012) (below). Based on these reviews and other information, options for research have been scoped (Malcolm et al., 2013) (below) and Marine Offshore Renewables Energy (MORE) and Freshwater Fisheries sectors have been consulted on priorities for investigation (Hunter et al., 2014). The consultation process has been overseen by the Salmonids-MORE Steering Group, which includes representation from MORE and wild fisheries sectors, and Scottish Government (policy, science and licensing operations).
Current research work includes several linked themes. First, satellite transmitters are being used to track behaviour of salmon captured on the north coast as they migrate toward home rivers. A total of 50 tags was deployed in 2013 and plans are in place to track a further 70 fish in 2014. This approach provides information on the depth use of adult salmon on their return migration and also limited data on the route followed (a single location is obtained from each fish when the tag pops up after a pre-set time interval and relays its position together with information it has recorded on depth, light levels and temperature throughout the timecourse of the deployment).
Second, investigation is underway into the potential for using single nucletide polymorphisms (SNPs) on genes to determine the rivers of origin of salmon captured at sea. If so, then it will be possible to determine where each of the satellite tagged salmon is most likely to have ultimately been heading. Such information may provide useful insights into the homing behaviour of salmon and also allow investigation of whether there are differences in depth use depending on how close the fish is to its natal river.
Third, investigations are underway into the effects (if any) of electromagnetic fields, such as fish may encounetr as they appropach cabling associated with energy generators. Apparatus has been constructed to generate controlled alternating current electromagnetic fields in a large laboratory tank. Salmon have been exposed to a range of field strengths at smolt and adult stages of their life cycle. Results of the trials are currently being analysed.