REGIONAL GROWTH PATTERNS OF JUVENILE ALBACORE (THUNNUS ALALUNGA) IN THE EASTERN NORTH PACIFIC
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Population structure of North Pacific albacore (Thunnus alalunga) may be more complex than the current single-stock hypothesis given the apparent regional differences in size-at-age and movement patterns in the eastern North Pacific. In this study, otolith-based techniques were used to analyze the age structure, daily growth rates and hatch dates of 126 albacore collected from two regions in the eastern North Pacific (northern: >40 N and southern: <40 N) in July through October of 2010 and 2011. Juvenile albacore collected from the southern region had significantly larger size-at-age than those collected from the northern region over a similar age range examined (423-1254 days). No significant regional difference in growth rates of juvenile albacore was detected over the ages examined, suggesting processes occurring in the first year and a half of life may have been driving regional size-at-age differences. Back-calculated hatch dates suggest protracted spawning for fish from both regions ranging from February to September with peak hatch dates between April and July (73% of all fish). Results from this two-year study suggest that juvenile albacore length-at-age estimates in the eastern North Pacific are region-specific and may need to be considered for future life history studies and stock assessments.
CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONS REPORTS
author list (cited authors)
Renck, C. L., Talley, D. M., Wells, R., & Dewar, H.
complete list of authors
Renck, Charlene L||Talley, Drew M||Wells, RJ David||Dewar, Heidi