Lost at Sea? The Atlantic Salmon’s Ocean Odyssey
A very interesting and well attended talk. There were three principle speakers Ken Whelan of the Atlantic Salmon Trust, Chris Todd from the University of St Andrews and John Armstrong from Marine Scotland Science.
Ken focused on the urgent need to understand why there is increasing marine mortality of Atlantic Salmon. In order to determine the reasons as to why this is happening it is vital that we fully understand the salmon’s migration. Fascinating work on this subject has been carried out by SALSEA and more information can be found by following the link below.
A better picture of salmon migration routes and feeding grounds is being built although there is a still a great deal of work to do and a lot of known unknowns to unravel. Ken also raised the simple issue of how the Salmon is categorised and to be fully integrated into marine strategy and protection packages then it needs to be thought of as a pelagic fish.
Chris focused on the marked decline in salmon weights. Since 2000 the condition of fish, (ie are they fat or thin) has deteriorated. As well as being physically slimmer the scales of these fish also reveal that the fish are having periods of growth checks, ie periods when food is scarce. Pre 2000 these growth checks were very rare, post 2000 they are all too common. What was also striking was the increase in temperature in the North Atlantic the effect that this would have on the distribution of prey items and the condition of the prey themselves.
John spoke about the changing Scottish Coastal environment and the challenges that the Atlantic Salmon will have to face in the form of coastal development- renewable technologies, power cables etc. There was interesting footage of salmon interacting with power cables similar to those that could be found in a renewable tidal project. It would appear that the salmon is unaffected, let us hope that this is the case. Work is being done on tracking salmon movements to help us understand the movements of fish and consequent interactions with man.
It is clear what that there is no quick fix. Indeed no solutions were offered nor could they be but great work is being carried out in an attempt to understand why these fish are in decline. There are of course some causes of marine mortality that we know all about. Namely the expanding Scottish salmon netting industry. I will return to this grim and unbelievable state of affairs in another post.