Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences

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Age and growth estimates of the blue shark, Prionace glauca, in the central South Pacific Ocean

Shoou-Jeng Joung , Guann-Tyng Lyu , Hua Hsun HSU , Kwang-Ming Liu , Shyh-Bin Wang


The age and growth of the blue shark, Prionace glauca, in the central South Pacific were described based on 267 specimens, that were collected by scientific observers on-board Taiwanese large-scale tuna longline fleets between May 2009 and May 2011. Growth band pairs (identified as translucent and opaque bands) were counted on images photographed from X-ray films of the vertebrae from the caudal peduncle region. The marginal increment ratio and centrum edge analysis indicated that a growth band pair on vertebral centrum was formed once a year. The band pairs after the birth mark were counted from 2-11 and 2-15 for females and males, respectively. The bias corrected Akaike Information Criterion indicated that the von Bertalanffy growth function (VBGF) best fitted the observed total length (TL)-at-age data. The parameters of sex-specific VBGF were estimated as follows: L = 376.6 ± 32.6 cm TL, k = 0.128 ± 0.022 year-1, and t0 = -1.482 ± 0.54 years for males, and L = 330.4 ± 46.6 cm TL, k = 0.164 ± 0.057 year-1, and t0 = -1.294 ± 0.78 years. The longevities were estimated to be at least 16.8 and 21.4 yrs for females and males, respectively.

MF17098  Accepted 26 January 2018

© CSIRO 2018