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The relation between early marine growth of pink salmon, Oncorhynchus gorbuscha, and marine water temperature, secondary production, and survival to adulthood

2000; National Oceanic and Atmospheric Administration; Issue: 2 Linguagem: Inglês

1937-4518

Donald G. Mortensen, A. C. Wertheimer, Caz M. Taylor, Joyce Hanson Landingham,

Marine Bivalve and Aquaculture Studies

Juvenile pink salmon, Onco - rhynchus gorbuscha, from four consecu- tive brood years were tagged as they emi- grated to the estuarine waters of Auke Bay, and information was obtained on the relationships between early marine growth, environmental conditions, and survival to adulthood. Juveniles that emigrated from Auke Creek later in the spring spent signifi cantly less time in the estuary. Individual growth rates of tagged fi sh recovered in Auke Bay ranged from 3.1% to 7.1% per day. In all study years, juvenile pink salmon grew more slowly in early April than in late April and early May. Water temperature and growth were signifi cantly correlated in all years, but growth did not consis- tently correlate with the biomass of epi- benthic prey or zooplankton available to the fi sh. Comparisons of expected and observed growth rates suggested that low prey availability, as well as low tem- peratures, may have limited growth for early spring emigrants. Although early emigrants encountered poorer growth conditions, survivors were larger at a given date than later emigrants, their larger size possibly protecting them from size-selective predation. Early marine growth was signifi cantly related to intra-annual cohort survival to adults (r2=0.65, P<0.05). Larger fi sh con- sistently survived better than their smaller cohorts for all years. Although early marine growth was an important determinate of survival within a cohort of pink salmon, other factors, such as predator abundance, contributed to the large interannual variability observed.