Spatial and Temporal Trends in Juvenile Sockeye Salmon Diets Across Oceanographic Regimes on the Coast of

Samantha James Evgeny Pakhomov & Brian Hunt

Research Aims

Measure juvenile sockeye diets across fine spatial and temporal scales to determine:

1)How much are they eating? Drivers? 2)What are they eating? Juvenile Salmon Program

4 Where?

Queen Charlotte Strait Mainland BC

Vancouver Vancouver Strait of Island Georgia

Pacific Ocean

5 Mainland Where? BC

Vancouver Vancouver Strait of Island Georgia

Pacific Queen Ocean Charlotte Strait Johnstone Strait

N.

Dosser in prep Queen Charlotte Strait Mainland Where? BC

Vancouver Vancouver Strait of Island Georgia

Pacific Ocean

Dosser in prep How?

Calculate Gut Fullness Index (GFI): 푀 푠푐 × 100 푀푓 Results: How much do they eat? Spatial

Queen Charlotte Strait Johnstone Strait Discovery Islands N. Strait of Georgia

North South IQR of gut fullness values for the entire coast (Brodeur et al. 2007) Results: How much do they eat? Temporal Johnstone Strait Discovery Islands

IQR gut fullness for northeast Pacific (Brodeur et al. 2007)

IQR sockeye outmigration (Johnson et al. 2018) Results: What are they eating? Spatial

Queen Charlotte N. Strait of Strait Johnstone Strait Discovery Islands Georgia

North South Results: What are they eating? Temporal Johnstone Strait Discovery Islands Results: What are they eating? Spatial Why?

Discovery Islands

Johnstone Strait

1 Cooler 2 Warmer Higher salinity Lower salinity Results: What are they eating? Teporal Why?

DI

JS Conclusions

Measure juvenile sockeye diets across fine spatial and temporal scales. 1)How much are they eating? Biological hotspots vs. low foraging success Inter- vs Intra- annual trends 2)What are they eating? Different prey in different areas over time Timing matters @sockeyejames References

Johnson, B.T., J.C.L. Gan, C.V. Janusson, and B.P.V. Hunt. 2018. Juvenile salmon migration dynamics in the Discovery Islands and Johnstone Strait; 2015–2017. NPAFC Doc. 1790. 10 pp. Hakai Institute, Institute for the Oceans and Fisheries and Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia (Available at http://www.npafc.org)

Brodeur, R.D., E.A. Daly, M.V. Sturdevant, T.W. Miller, J.H Moss, M. Thiess, M. Trudel, L.A. Weitkamp, J. Armstrong, and E.C. Norton. 2007. Regional Comparisons of Juvenile Salmon Feeding in Coastal Marine Waters off the West Coast of . American Fisheries Society Symposium, 57