Science Advisory Report  2012/007

Recovery Potential Assessment for the South Newfoundland Atlantic Salmon (Salmo salar) Designatable Unit

Summary

• The South Newfoundland Atlantic salmon (Salmo salar L.) DU 4 comprises Salmon Fishing Areas (SFAs) 9-12 and the population is estimated to have declined by 42.4% over the last three generations (1996-2010; small salmon 41.5% and large salmon 48.3%).
• The most substantial estimated decline occurred in SFA 11 which strongly influenced the total abundance for DU 4.
• Marine survival (smolts to adult) is variable in DU 4, averaging 4% (± 2%), and seems to have declined more in SFA 11 than in SFA 9, as evidenced by Conne River’s (SFA 11) decline of 61.6% from 1987-2010; Northeast Brook’s (SFA 9) 18% decline (1986-2010); and Rocky River’s increase of 33.5% (1991-2010). 
• Population projections over three generations (15 years) and under different recreational fishery management scenarios were undertaken for the South Newfoundland (DU 4) Atlantic salmon population to estimate the probabilities of: (1) maintaining current population levels, (2) achieving the Conservation Requirement, and (3) achieving the Pre-Decline Mean (1981-1995).
• According to these projections, under contemporary marine and angling mortality rates, there is a 50% chance that the DU 4 population will drop below its current size. There is a 23% chance of achieving the Conservation Requirement and 12% chance of achieving the Pre-decline mean.
• Under a “no-angling” scenario and a contemporary marine survival rate of 4% (± 2%), there is a 74% chance that the population will remain at or exceed its current size. There is a 52% chance of achieving the Conservation Requirement and 27% chance of achieving the Pre-decline mean.
• Under a “catch-and-release only” angling scenario and a contemporary marine survival rate of 4% (± 2%), there is a 70% chance that the population will remain at or exceed its current size.  There is a 42% chance of achieving the Conservation Requirement and 26% chance of achieving the Pre-decline mean.
• According to these projections, over the next three generations (15 years) a minimum 5% average marine survival, at contemporary angling levels, would be required to have a 75% chance of maintaining or exceeding the current population size. To achieve the Conservation Requirement, marine survival would need to increase to an average of 6% and increase to an average of 7% to achieve the Pre-decline mean.
• Under a “no-angling” scenario, a minimum 5% average marine survival would be required to have a 75% chance of maintaining or exceeding the current population size. To achieve the Conservation Requirement, marine survival would need to be an average of 5% and increase to an average of 6% to achieve the Pre-decline mean.
• Under a “catch-and-release only” angling scenario, a minimum 5% average marine survival would be required to have a 75% chance of maintaining or exceeding the current population size. To achieve the Conservation Requirement marine survival would need to be an average of 5% and increase to an average of 6% to achieve the Pre-decline mean.
• Freshwater habitat quality and quantity are not thought to be limiting the production or recovery of DU 4 salmon. 
• The greatest threat to the recovery of the South Newfoundland Atlantic salmon population is continued low marine survival. Factors influencing marine survival may include: illegal fisheries, mixed-stock marine fisheries and by-catch, ecological and genetic interactions with escaped domestic Atlantic salmon, and changes in marine ecosystems. The degree of influence of these factors is unknown and many have the potential to affect salmon in other DUs where populations have been stable or increasing.
• Understanding the possible unique factors that impact the biological condition of Atlantic salmon during the marine phase of their life-cycle and marine habitat quality within the DU 4 area are key knowledge gaps that need to be addressed.

This Science Advisory Report has resulted from a Fisheries and Oceans Canada, Canadian Science Advisory Secretariat, Regional Advisory Meeting of February 14-16, 2012 on the Recovery Potential Assessment (RPA) of South Newfoundland Atlantic salmon DU. Additional publications from this process will be posted as they become available on the DFO Science Advisory Schedule.

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