What assessment it has made of the numbers of non-native pink salmon present in Scottish rivers.

In recent weeks, anglers in at least 18 Scottish rivers and netting stations in the River Esk and Tweed have reported historically unprecedented numbers of fresh run non-native pink salmon. As at the end of August, Fisheries Management Scotland (FMS) have records that approximately 140 have been caught in Scotland.
Pacific pink salmon were originally introduced to some Russian rivers in the 1960s, have slowly spread westwards and have now colonised some northern Norwegian rivers. The fish spawn at a different time from Atlantic salmon, have a 2-year lifecycle and generally spawn in summer (and often in main river channels, in the lower reaches of rivers, and sometimes in upstream tributaries).
Whilst it is theoretically possible that these non-native species could establish themselves in Scottish rivers, the higher water temperatures make this unlikely. However, since the risks have not been formally quantified the Scottish Government is in on-going dialogue with the GB Non-Native Species Secretariat to establish a formal, peer reviewed, risk assessment particularly in respect of the potential impact this could have on Scotland’s wild salmon populations.
In parallel, Marine Scotland Science (MSS) is undertaking a series of investigations which will allow refinement of the GB risk assessment to local Scottish rivers and will inform decisions on subsequent management options.
MSS is using information from its National Temperature Monitoring Network to assess the likelihood of successful spawning by pink salmon across Scotland.
If viable eggs are available from the pink salmon, then MSS will test them in the marine laboratory in Aberdeen to assess the temperature limits for successful development and hatching. Ideally, we would like to obtain viable eggs by stripping pre-spawned fish. However, if this is not possible or we obtain insufficient eggs via this method, we are also planning the excavation of redds, at a point where the eggs are ‘eyed’ and therefore at their most robust. If both methods fail, MSS will use published data from other stocks.
MSS is also working with Fisheries Management Scotland to monitor the success of pink salmon eggs deposited within certain rivers, using specially designed hatching chambers that hold eggs within the river substrate with attached surface chambers which, together, can be used to assess survival and emergence of eggs/fry.
MSS will use genetics methods to assess the likely origins of the fish. This objective will be achieved by comparing the genetics of the invasive pink salmon with a library of pink salmon genetics signatures collated by International collaborators.
Meantime, our Fish Health Inspectorate will sample any fish which are moribund or displaying clinical signs of disease in order to identify parasites and/or pathogens which they may carry.
District Salmon Fishery Boards also remain empowered to take a different course of action, such as destroying redds and trying to net out the fish. Where necessary the Scottish Government will considering licencing them to do so. One licence application is currently being considered.
SNH is conveying a meeting of experts, including participants from Norway and Denmark, on 21 September to share their experiences and management activity surrounding pink salmon.
The information to date suggests that Scottish rivers are witnessing what is termed an odd year cycle. If this is confirmed, the Scottish Government will continue to work with Fisheries Management Scotland, its member boards and trusts, SNH and SEPA so that we are fully prepared, with clear strategies, if/when pink salmon return in 2019.