Determination of age and growth of south Pacific albacore (Thunnus alalunga) using three methodologies

• Published in: Fishery bulletin (Washington, D.C.) Vol. 91; no. 4; pp. 649 - 663
• Main Authors: Labelle, M, Hampton, J, Bailey, K, Murray, T, Fournier, DA, Sibert, J R
• Format: Journal Article
• Language: English
• Published: 01.01.1993
• Subjects: Marine; Thunnus alalunga; PSW, South Pacific
• ISSN: 0090-0656

Length-frequency data, vertebral-ring-counts, and length measurements of tagged fish were analyzed to independently estimate von Bertalanffy growth parameters for south Pacific albacore (Thunnus alalunga). As a working hypothesis, we assumed that the length-frequency modes and vertebral-rings are annual features. The MULTIFAN model fitted to length-frequency data provided estimates of L sub( arrow left ) and K of 97.1 cm and 0.239/year, respectively. Nine age classes were detected in the data. Growth varied seasonally: growth rate decreased to almost zero during August and peaked during February. Two to thirteen rings were visible in the vertebrae, and estimates of L sub( arrow left ) and K of 121.0 cm and 0.134/year, respectively, were obtained. No significant differences in growth parameters were detected between males and females. The growth rates predicted by the length-frequency and vertebral-ring-count models were very similar throughout the range of presumed age classes in both data sets. These growth rates were consistent with length increment observations from 28 tag returns, which lends support to our assumptions of annual vertebral-rings and length-frequency modes.