For reasons not understood, mortality rates for Atlantic salmon at sea are double those of the 1970s.
Nevertheless, through the tracking research conducted by ASF, some answers have been found. ASF has been an important leader in developing the technology, in concert with VEMCO, the engineering company involved, with government, and more recently with the Ocean Tracking Network that has been created with headquarters at Dalhousie University.
Read more on ASF's smolt tracking program
ASF's research is providing a window showing where high predation occurs, differences from one year to the next, and ways to advance the technology.
The graph below provides insight on smolt survival to the Strait of Belle Isle.
From the line of detectors at the Strait of Belle Isle, it is evident that survival in general has improved over the past few years, although some rivers, such as the Cascapedia, have higher variability in survival rates. It is thought that predation in estuaries may be playing an important part in smolt mortality.
Why the Riviere St-Jean (QC North Shore) has such a low survival rate is uncertain. It is possible the smolt are actually travelling south of Newfoundland. If so, there should be more information this year, now that the OTN has completed a line of receivers across Cabot Strait from Cape Breton to near Port aux Basques.
Improved Productivity At Sea
There is some evidence that productivity at sea around Newfoundland has improved over the past two years, and this may also be improving the food supply and, therefore, both the health and survival rates of wild Atlantic salmon.
The Greenland Conservation Agreement
Since 2003, an agreement, developed by ASF and the North Atlantic Salmon Fund (NASF) has been in place for Greenland fishermen. In exchange for refraining from commercially harvesting Atlantic salmon off their coast, Greenland fishermen have received assistance with employment development in other areas. There is considerable evidence that, over time, this has allowed more large Atlantic salmon to return to their home rivers in North America. Read more on Greenland Interceptory Fisheries
The Present Situation
While 2011 was an excellent year for Atlantic salmon returns to North America, when compared with those of the previous decade, many of the rivers in the Bay of Fundy, those on Nova Scotia's outer coast, and the rivers on the south coast of Newfoundland did not respond with higher returns.
Endangered Atlantic salmon populations are, therefore, at particular risk from the high mortality rates still being experienced. Read more about Endangered Status for Atlantic salmon