Inter-Annual Patterns in Stage-Specific Feeding, Growth, and Survival of Juvenile Pink Salmon in the Gulf of Alaska

• Main Authors: David A. Beauchamp, Alison D. Cross, Jamal H. Moss
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Growth; survival; pink salmon; Gulf of Alaska; Prince William Sound All correspondence should be addressed to D.A. Beauchamp; Pink salmon; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.620.2538; http://www.npafc.org/new/publications/Technical Report/TR7/Beauchamp.pdf

Evidence is mounting for the positive relationship between marine survival of salmon and larger juvenile size or higher growth rates, but little is known about the precise timing of critical life stages or the mechanisms underlying size-selective marine mortality. The temporal dynamics and variety of factors that potentially affect distribution, growth, and survival can confound determinations of the processes that most influence performance during critical life stages in the ocean. Hatcheries in Prince William Sound (PWS) release approximately 600 million otolith-marked juvenile pink salmon annually, and these hatchery fish represent the largest biomass of juvenile salmon in the eastern coastal Gulf of Alaska (GOA). Pink salmon are considered the primary zooplankton consumers in this region. Juvenile pink salmon in PWS and the coastal GOA exhibited a three-fold difference in marine survival during the GLOBEC sampling program in 2001–2004. For otolith-marked hatchery pink salmon released in PWS Sound during 2001–2004, we investigated the relationship of growth and size-selective mortality during and after the first growing season. Using a bioenergetics model, we examined monthly and inter-annual patterns in spatial distribution, thermal experience, growth, and diet composition to relate feeding and growth performance to inter-annual variability in stage-specific mortality and total ocean survival. During 2001–2004, monthly sampling cruises were conducted from July through September or October at three sites in PWS and six or more sites along the Seward Line (GAK 1-6) in the coastal Gulf of Alaska (GOA).