Skeena River Estuary Juvenile Salmon Habitat May 21, 2014 Research carried out by Ocean Ecology 1662 Parmenter Ave. Prince Rupert, BC V8J 4R3 Telephone: (250) 622-2501 Email: [email protected] Skeena River Estuary Skeena River Estuary Juvenile Salmon Habitat Skeena Wild Conservation Trust 4505 Greig Avenue Terrace, B.C. V8G 1M6 and Skeena Watershed Conservation Coalition PO Box 70 Hazelton, B.C. V0J 1Y0 Prepared by: Ocean Ecology Cover photo: Brian Huntington Ocean Ecology Skeena River Estuary Table of Contents Table of Contents ............................................................................................................................. ii List of Figures .................................................................................................................................. iii List of Tables ................................................................................................................................... iv Executive Summary ......................................................................................................................... vi 1 Introduction ............................................................................................................................... 7 1.1 Chatham Sound ................................................................................................................ 7 1.2 Skeena River Estuary ..................................................................................................... 10 1.3 Environmental Concerns ................................................................................................. 13 1.4 Study Purpose ................................................................................................................. 16 2 Methodology ........................................................................................................................... 18 2.1 Model Approach .............................................................................................................. 18 2.2 Estuarine Habitats of Importance to Juvenile Salmon .................................................... 19 2.3 Model Assumptions from Best Available Science ........................................................... 20 2.4 Key Habitat Factors ......................................................................................................... 22 3 Salmon Life Histories in the Skeena River Watershed .......................................................... 25 3.1 Chinook Salmon .............................................................................................................. 25 3.2 Pink Salmon .................................................................................................................... 28 3.3 Chum Salmon ................................................................................................................. 30 3.4 Sockeye Salmon ............................................................................................................. 32 3.5 Coho Salmon .................................................................................................................. 34 3.6 Steelhead ........................................................................................................................ 36 3.7 Sea-run Coastal Cutthroat Trout ..................................................................................... 38 3.8 Average Stage-Specific Survival Rates for Different Salmon Species ........................... 40 3.9 Outmigration of Juvenile Salmonids from the Skeena River .......................................... 40 4 Results and Discussion .......................................................................................................... 47 5 Conclusions and Recommendations ...................................................................................... 58 6 Acknowledgments .................................................................................................................. 60 7 Glossary ................................................................................................................................. 61 8 References Cited .................................................................................................................... 84 9 Appendix................................................................................................................................. 95 9.1 Model Hypotheses/Assumptions ..................................................................................... 95 9.2 Morphological Classifications ........................................................................................ 102 9.3 Food Habitat Factor ...................................................................................................... 102 9.4 Flow Habitat Factor ....................................................................................................... 105 9.5 Obstructions Habitat Factor .......................................................................................... 106 9.6 Habitat Diversity Habitat Factor .................................................................................... 106 9.7 Chemicals Habitat Factor .............................................................................................. 109 9.8 Oxygen Habitat Factor .................................................................................................. 110 9.9 Temperature Habitat Factor .......................................................................................... 110 9.10 Sediment Load Habitat Factor ................................................................................... 110 9.11 Intraspecific Competition with Hatchery Fish Habitat Factor ..................................... 111 9.12 Interspecific Competition with Other Species Habitat Factor .................................... 112 9.13 Predation Habitat Factor............................................................................................ 115 9.14 Species-specific Habitat Utilization Adjustment Factors ........................................... 116 9.15 Environmental Attributes ........................................................................................... 117 10 Disclaimer ......................................................................................................................... 133 ii Ocean Ecology Skeena River Estuary List of Figures Figure 1. Aerial view north over Chatham Sound. Photo: Brian Huntington. ................................. 7 Figure 2. Skeena estuary classification during freshet flow conditions. .......................................... 8 Figure 3. Skeena and Nass River inputs into Chatham Sound. ...................................................... 9 Figure 4. Aerial view of the Skeena River estuary looking northeast over Kitson Island, Flora Bank, and Lelu Island. Ridley Island is on the left hand side of the photo. Porpoise Channel is shown as a gap between Lelu and Ridley Islands. The proposed terminal for the Prince Rupert LNG would be located on southern Ridley Island along the north side of Porpoise Channel. The proposed terminal for the Pacific Northwest LNG would be located on Lelu Island along the south side of Porpoise Channel. Photo: Brian Huntington. ....................................................................................................................... 10 Figure 5. Skeena watershed, showing the location of major tributaries and communities (Walters et al. 2008). ....................................................................................................................... 11 Figure 6. Mouth of the Skeena River estuary. ............................................................................... 13 Figure 7. Location of current and proposed marine industrial activities in the Skeena River estuary region. ............................................................................................................................... 14 Figure 8. Location of proposed marine industrial activities, and their associated dredge sites, in the areas around southern Ridley Island, Lelu Island, and Flora Bank. .......................... 15 Figure 9. Juvenile salmon. Photo: Ken Rabnett. .......................................................................... 19 Figure 10. Juvenile Chinook salmon. Photo: Ken Rabnett. .......................................................... 26 Figure 11. Estuarine habitat utilization and coastal distribution of Chinook salmon (Williams 1989). ................................................................................................................................ 27 Figure 12. Juvenile pink salmon. Photo: Ken Rabnett. ................................................................ 28 Figure 13. Habitat utilization and coastal distribution of pink salmon (Williams 1989). ................. 29 Figure 14. Juvenile chum salmon. Photo: Ken Rabnett. .............................................................. 30 Figure 15. Habitat utilization and coastal distribution of chum salmon (Williams 1989). .............. 31 Figure 16. Juvenile sockeye salmon. Photo: Ken Rabnett. .......................................................... 32 Figure 17. Habitat utilization and coastal distribution of sockeye salmon (Williams 1989). .......... 33 Figure 18. Juvenile Coho salmon. Photo: Ken Rabnett. .............................................................. 34 Figure 19.