Science Advisory Report 2018/034

Stock Assessment of Newfoundland and Labrador Atlantic Salmon – 2017

Summary

• Nineteen populations of Atlantic Salmon were assessed in 2017. Adult salmon were counted on four rivers in Labrador and fifteen rivers in Newfoundland. Five of the fifteen assessed rivers in Newfoundland also counted juvenile salmon (smolt) migrating to sea.
• In 2017, fifteen monitored rivers showed declines in total returns, and twelve of these fifteen rivers had declines of greater than 30% compared to their previous five-year mean. For four rivers, data were unavailable to compare 2017 returns to the previous five-year mean.
• Two consecutive years of declines of this magnitude over a wide geographic range are highly unusual for the NL Region since the commercial moratorium (1992).
• In 2017, river status on the basis of returns is similar to that based on spawners.
• In 2017, spawning escapements (eggs) were below the river-specific Limit Reference Point (LRP) on three of the four assessed rivers in Labrador; however, spawning escapement of the fourth river exceeded its Upper Stock Reference Point (USR).
• In Newfoundland, spawning escapements (eggs) were below the LRP for nine of the fifteen (60%) assessed rivers. Of the remaining Newfoundland rivers assessed in 2017, five out of fifteen (33%) rivers exceeded the USR and one assessed river fell within the cautious zone (between the LRP and USR).
• Marine survival continues to be the major factor limiting the abundance of Atlantic Salmon within the region. Returns in any given year are determined primarily by marine survival rather than variations in smolt production. Inter-annual variation in marine survival continues to fluctuate, with survival in 2017 ranging between 3.7% and 7.7% for the three monitored rivers where marine survival estimates were available.
• Estimated Labrador Aboriginal and subsistence fisheries harvest was inferred from logbook returns (56% return rate) at 13,600 salmon in 2017 (7,200 small, 6,400 large), which was 4% less than the previous six-year mean (2011-16) of 14,100 salmon (9,000 small, 5,100 large).
• Genetic analysis of Atlantic Salmon in Labrador fisheries (2006-16) indicated that the majority of salmon were of Labrador origin (95-99%).
• Estimates of recreational catches for NL have been highly variable since 2005 (total catch range of 38,900 to 76,100 salmon). Preliminary estimates of retained and released salmon in 2017 were approximately 19,400 and 22,800, respectively.
• Status of Atlantic Salmon on the south coast of Newfoundland (SFAs 9-11) remains poor. Returns to Conne River in 2017 were only 710 fish, the lowest on record over the 32-year time series, and were equivalent to only 32% of the LRP. Marine survival rates remain low at less than 4% in most recent years. There is evidence of hybridization between wild and farmed salmon juveniles throughout Fortune Bay and Bay d’Espoir and the long-term consequences of this on wild salmon populations are uncertain.
• A regional Composite Climate Index of various measures of meteorological, sea ice, ocean temperature and salinity conditions shows a warming trend since the mid-1990s that peaked in 2010, but thereafter decreased to mostly below normal conditions during the past four years. Such broad-scale ocean climate conditions are associated with primary and secondary production indices in the northwest Atlantic region. The large reduction in zooplankton biomass observed since 2015 indicates lower potential energy transfer to higher trophic levels including Atlantic Salmon.
• Sea ice departure in the inshore regions along the east and northeast coast of Newfoundland in 2017 was delayed by up to 45 days in some areas resulting in a significant delay (up to 50 days) in the spring warming (to 3°C) of inshore coastal waters.
• The consequences of these environmental conditions on total returns of salmon in 2017, survival rates of smolts migrating in 2017 and adults returning in 2018 are unknown.
• There were large unexpected declines in 2016 and 2017 in Atlantic Salmon returns. Expected returns in 2018 cannot be accurately predicted. Based on the experience of 2017, an in-season evaluation of returns to date with projections for the end-of-year abundance accurately predicted the returns for 2017. A similar approach could be considered for 2018.

This Science Advisory Report is from the February 28 to March 1, 2018 Regional Peer Review Process on the Assessment of Atlantic Salmon in NL. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Scheduleas they become available.

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