Meeting Abstract

P1.118  Friday, Jan. 4  Preparation for freshwater migration in adult pink salmon (Oncorhynchus gorbuscha) BYSTRIANSKY, J.S.*; SACKVILLE, M.; YOO, J.; TATTERSALL, K.; ALONGE, M.M.; JUDD, S.M.; FARRELL, A.P.; BRAUNER, C.J.; DePaul University; University of British Columbia; University of British Columbia; University of British Columbia; DePaul University; DePaul University; University of British Columbia; University of British Columbia jbystria@depaul.edu

Despite decades of research on smoltification of salmon during their seaward migration, very little is understood about whether salmon undergo a similar physiological preparation for freshwater re-entry during their spawning migration. Pink salmon reach maturity and return to freshwater at two years of age. Exceptions to this rule are very rare making pinks the ideal species to study seasonal changes in osmoregulatory capacity. This study examined the expression and activity of gill H+-ATPase and several isoforms of Na+K+-ATPase in lab-reared pink salmon held in seawater over an 19 week period coinciding with the period prior to, during and after the timing of their natural freshwater migration. Muscle water content and plasma sodium and chloride concentrations were determined to assess the osmoregulatory status of pink salmon throughout the study period and discussed in relation to observed changes in gill ion transporter expression and activity.