Beach seining for juvenile salmon

Surface trawling for juvenile salmon during a cooperative ADF&G and NOAA research cruise on the R/V MEDEIA

Pacific salmon migrate from freshwater rearing habitats to the marine environment, where they spend from 1 to 6 years (depending on species) before returning to their natal rivers to spawn. Mortality during marine residency is high and variable, ranging from less than 80% to over 99%. Much of this mortality occurs during the first few months of marine residency in estuarine, nearshore, and coastal waters.

The migration of juvenile salmon to marine habitats has evolved to be synchronous with the spring bloom of primary and secondary production characteristic of subarctic marine ecosystems. Favorable marine conditions have been a major reason for the high productivity of Alaska salmon in recent decades. However, evidence of density dependent growth, declining size at return in some populations, and increased hatchery production in some regions of the state have led to concern about ocean carrying capacity, and about when and where bottlenecks to growth and survival of juvenile salmon occur.

Research by the Early Ocean Salmon (EOS) Task of the MSI Program focuses on the marine ecology of juvenile salmon in order to increase our knowledge of factors affecting salmon during this critical phase of their life history. EOS scientists are examining relationships between marine conditions and growth of salmon with subsequent survival and size at maturity, the environmental conditions defining juvenile salmon habitat, and how climate change may influence these relationships. This research has provided insights into interactions of juvenile salmon with other pelagic species, mortality rates during initial marine residency, carrying capacity of neritic habitats for juvenile salmon, hatchery and wild salmon interactions in marine environments, density effects on size at return of pink salmon, and forecasting year-class strength of pink salmon. Current research is organized under four themes.

1. Southeast Alaska Coastal Monitoring (SECM)
2. Fish, Energy, Diet, and Zooplankton (FEDZ) Laboratory
3. GLOBEC: Juvenile Coho Salmon Studies in Neritic Waters of Southeast Alaska
4. Regional variation in marine survival of chum salmon in Southeast Alaska

Contact:
Alex Wertheimer
Auke Bay Laboratories
Alaska Fisheries Science Center, NOAA Fisheries

Ted Stevens Marine Research Institute
17109 Pt Lena Loop Rd
Juneau, AK 99801
(907) 789–6040
Alex.Wertheimer@noaa.gov

Featured Research, Publications, Posters, Reports, and Activities

• BRODEUR, R. A., E. A. DALY, M. V. STURDEVANT, T. W. MILLER, J. H. MOSS, M. E. 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 North America, p. 183-203. In C. B. Grimes, R. D. Brodeur, L. J. Haldorson, and S. M. McKinnell (editors), Ecology of Juvenile Salmon in the Northeast Pacific Ocean: Regional Comparisons. Am. Fish. Soc. Symp. 57. Bethesda, Maryland. 
   
• Sablefish Predation on Juvenile Salmon in the Coastal Marine Waters of Southeast Alaska in 1999
  By:  M. V. STURDEVANT, M. F. SIGLER, J. A. ORSI
  Conference:  Alaska Marine Science Symposium, Anchorage, AK, Jan 2009
  (2009 poster, .pdf, 196KB)   Online.
   
• Diel Feeding and Gastric Evacuation of Juvenile Salmon
  By:  M. V. STURDEVANT, E. A. FERGUSSON, J. A. ORSI, A. C. WERTHEIMER
  Conference:  GLOBEC Ocean Sciences Meeting, Portland, OR, Jan 2004
  (2004 poster, .pdf, 341KB)   Online.
   

See the publications and poster databases for additional listings.