Status of Atlantic Salmon Stocks in Rivers of Nova Scotia Flowing Into
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Canadian Science Advisory Secretariat (CSAS) Research Document 2015/043 Gulf Region Status of Atlantic salmon (Salmo salar L.) stocks in rivers of Nova Scotia flowing into the Gulf of St. Lawrence (SFA 18), 2012-2013 M. Biron and C. Breau Science Branch, Aquatic Resources Division Gulf Region Fisheries and Oceans Canada P.O. Box 5030 Moncton, NB E1C 9B6 December 2015 Foreword This series documents the scientific basis for the evaluation of aquatic resources and ecosystems in Canada. As such, it addresses the issues of the day in the time frames required and the documents it contains are not intended as definitive statements on the subjects addressed but rather as progress reports on ongoing investigations. Research documents are produced in the official language in which they are provided to the Secretariat. Published by: Fisheries and Oceans Canada Canadian Science Advisory Secretariat 200 Kent Street Ottawa ON K1A 0E6 http://www.dfo-mpo.gc.ca/csas-sccs/ [email protected] © Her Majesty the Queen in Right of Canada, 2015 ISSN 1919-5044 Correct citation for this publication: Biron, M., and Breau, C. 2015. Status of Atlantic salmon (Salmo salar L.) stocks in rivers of Nova Scotia flowing into the Gulf of St. Lawrence (SFA 18), 2012-2013. DFO Can. Sci. Advis. Sec. Res. Doc. 2015/043. viii + 40 p. TABLE OF CONTENTS LIST OF TABLES ........................................................................................................................ IV LIST OF FIGURES ...................................................................................................................... V ABSTRACT ................................................................................................................................ VII RESUME ................................................................................................................................... VIII INTRODUCTION .......................................................................................................................... 1 ATLANTIC SALMON FISHERIES ................................................................................................ 1 FIRST NATIONS FISHERIES ................................................................................................... 1 First Nations harvests ........................................................................................................... 2 RECREATIONAL FISHERY ...................................................................................................... 2 Angling statistics from license stubs ..................................................................................... 3 CONSERVATION REQUIREMENTS ........................................................................................... 4 SFA 18A .................................................................................................................................... 4 SFA 18B .................................................................................................................................... 4 Estimates of salmon returns to Margaree River .................................................................... 5 Estimates of salmon returns to SFA 18 ................................................................................. 5 Estimates of spawners in Margaree River ............................................................................ 5 Estimates of spawners in SFA 18 ......................................................................................... 6 JUVENILE ATLANTIC SALMON ABUNDANCE ........................................................................... 6 SFA 18A .................................................................................................................................... 6 MARGAREE RIVER (SFA 18B) ................................................................................................ 7 Juvenile salmon densities and growth in the Margaree River ............................................... 7 ATLANTIC SALMON OF HATCHERY-ORIGIN ............................................................................ 7 ABUNDANCE INDICATORS ........................................................................................................ 8 SOURCES OF UNCERTAINTIES ................................................................................................ 8 ACKNOWLEDGMENTS ............................................................................................................... 9 REFERENCES ........................................................................................................................... 10 APPENDICES ............................................................................................................................. 34 iii LIST OF TABLES Table 1. Atlantic salmon harvest allocations to aboriginal communities in rivers of Nova Scotia flowing into the Gulf of St. Lawrence in 2012. ............................................................................. 12 Table 2. Atlantic salmon harvest allocations to aboriginal communities in rivers of Nova Scotia flowing into the Gulf of St. Lawrence in 2013. ............................................................................. 13 Table 3. Recreational effort (rod days) and catch of Atlantic salmon by size group in Gulf Nova Scotia rivers, 1984 to 2013. SFA 18A refers to rivers on mainland Nova Scotia and SFA 18B to rivers in Cape Breton. ................................................................................................................. 14 Table 4. The conservation egg requirements and spawner requirements for the Gulf Nova Scotia rivers of SFA 18 (from Breau 2012). ................................................................................ 15 Table 5. Small and large salmon return estimates to the Margaree River, 1984 to 2013. .......... 16 Table 6. The numbers and percentages of small and large salmon of wild-origin and hatchery- origin (clipped adipose fin) that were reported caught by recreational anglers in the Margaree River during 2000 to 2013. The data were collected by anglers who volunteered to participate in a logbook program in Nova Scotia. ............................................................................................. 17 iv LIST OF FIGURES Figure 1. Salmon Fishing Areas (SFA) in eastern Canada. SFA 18 refers to rivers in Nova Scotia that flow into the Gulf of St. Lawrence. ............................................................................ 18 Figure 2. Rivers in Gulf Nova Scotia (SFA 18) that flow into the southern Gulf of St.Lawrence. Index numbers refers to river names as presented in Breau et al. (2009). ................................. 19 Figure 3. The number of recreational Atlantic salmon licenses sold in Nova Scotia and the annual estimated angling effort in mainland Gulf-Nova Scotia (SFA 18A) and western Cape Breton (SFA 18B). ....................................................................................................................... 19 Figure 4. Angling catch of small salmon (upper panel) and large salmon (lower panel) for mainland Gulf-Nova Scotia (SFA 18A) and western Cape Breton (SFA 18B), 1984 to 2013. .... 20 Figure 5. Angling catches of small and large salmon with effort for the three index rivers of mainland Nova Scotia (SFA 18A), 1984 to 2013. ....................................................................... 21 Figure 6. Catch per rod day for small salmon (upper panel) and large salmon (lower panel) for the three index rivers of mainland Nova Scotia (SFA 18A), 1984 to 2013. ................................. 22 Figure 7. Angling catch with effort (upper panel) and catch per rod day (lower panel) of small and large Atlantic salmon in the Margaree River (SFA 18B), 1984 to 2013. .............................. 23 Figure 8. Estimates of returns (upper panel) and spawners (lower panel) for small and large salmon in the Margaree River during 1987 to 2013. The conservation requirement based on large salmon is depicted by the dashed line (1,036 large salmon). Vertical bars represent the 2.5% and 97.5% credibility intervals. .......................................................................................... 24 Figure 9. Estimates of returns (upper panel) and spawners (lower panel) for small salmon in the Margaree River during 1987 to 2013. The conservation requirement based on sex ratio of 1 is depicted by the dashed line (582 small salmon). Vertical bars represent the 2.5% and 97.5% credibility intervals. ...................................................................................................................... 25 Figure 10. Estimates of returns (upper panel) and spawners (lower panel) for large salmon in the Margaree River during 1987 to 2013. The conservation requirement based on large salmon is depicted by the dashed line (1036 large salmon).Vertical bars represent the 2.5% and 97.5% credibility intervals. ...................................................................................................................... 26 Figure 11. Estimates of returns and spawners for small (upper panel) and large (lower panel) Atlantic salmon in SFA 18 during 1970 to 2013. Vertical bars represent the 2.5% and 97.5% credibility intervals. ...................................................................................................................... 27 Figure 12. Density of fry and parr per 100 m2 in River Philip, East River (Pictou) and West River (Antigonish),