Why study salmon at sea?
Salmon stocks have declined in both Europe and North America and all evidence points to there having been changes in the ocean phase.
It is not known where these changes have occurred, but they may be associated with factors operating in particular oceanic areas or at particular times.
Many of the problems that might have accounted for the decline in stocks have been eliminated, or have been or are being addressed.
The main outstanding problem is related to factors at sea, which is why marine research is urgently required.
What do we know about the marine ecology of salmon?
Current knowledge of the distribution and migration of salmon in the sea has been derived from commercial fisheries (West Greenland, Faroes, Norwegian Sea) and limited numbers of research surveys, which have principally been undertaken in the Norwegian Sea, Labrador Sea and the Gulf of Maine.
This sampling has not previously been undertaken in a co-ordinated fashion but provides a coarse picture of the origins and movements of salmon at sea.
While significant gaps in our knowledge remain, previous research provides clues as to what may be driving marine mortality e.g. common patterns of decline in widely separated stocks suggest problems where fish co-occur; survival at sea appears to be linked to post-smolt growth; and condition of salmon varies between years and some show signs of growth checks in their first sea year in some years.
What key things don't we know about salmon at sea?
Areas where our knowledge is limited include: when, where, why or how salmon are dying at sea; the distribution, migration and survival of smolts from emigration to the first summer at sea; the relative location of stocks in the sea that are doing well compared to those doing badly; and the relationship between the distribution of salmon and their prey.
Why is a coordinated marine research programme required?
The benefits of working together in a collaborative programme include more efficient sharing of facilities and pooling expertise, co-ordination of surveys in time and space, and making best use of existing information. The survey programme will concentrate upon areas where stocks from many rivers are thought to be present at the same time.