8. Impacts on wild and farmed salmon
8.1.1 Wild salmon populations
Stocks of wild salmon in Scotland have been in long-term decline, Scottish Government recognises the problem is down to a range of complex factors and have identified 12 high-level groups of pressures on wild salmon, which include predation.
The option to offset increasing mortality of salmon at sea by reducing catches in coastal net fisheries has been exhausted now that those fisheries have closed. Consequently, further declines in numbers of salmon returning from sea are now causing direct reductions in spawning stocks. Rod catch is an indicator of the wild salmon spawning stock. The total reported rod catch (retained and released) of wild salmon for 2019 is 47,515, the fourth lowest since records began in 1952.
There has been a year-on-year decrease in the numbers of rivers in which salmon stocks are achieving acceptable conservation status, as assessed under the Conservation of Salmon (Scotland) Regulations 2016. These regulations enforce a system to manage the killing of Atlantic salmon in inland waters by river fisheries. In 2019, 98% of rod caught spring multi sea-winter fish (taken before 1 May) were released, as were 92% of the annual rod catch (for wild salmon).
Reduction in levels of predation (including that from seals) can be expected to increase the conservation status of salmon stocks in many Scottish rivers. While Scottish Government continues to proactively explore new and novel non-lethal deterrent methods as outlined above, there may be a need for some limited lethal management of seals for conservation purposes in the future, where non-lethal alternatives have failed.
8.1.2 Health and welfare of farmed fish
The health and welfare of farmed fish is of crucial importance and improving the health and reducing losses is a long-term objective of the Farmed Fish Health Framework. Farmed fish are also protected from 'unnecessary suffering' by the Animal Health and Welfare (Scotland) Act 2006.
It is important to consider that nets do not keep seals away from farmed fish altogether and even if a seal cannot get direct access to predate stock in pens, the presence of a predator in close proximity may create stress which can lead to other health and welfare issues such as increased susceptibility to disease. The presence of predators such as seals can also bring about a flight response, panic swimming and with no way of escape it can cause crowding and reductions in oxygen that promote further health and welfare concerns.