The distribution pattern and the age and growth of Blue Sharks Prionace glauca were described based on 44,092 and 785 specimens, respectively, that were collected by scientific observers onboard Taiwanese longline fleets in the South Atlantic Ocean between December 2004 and December 2013. Size segregation was found, and the mean length of Blue Sharks was significantly larger in the equatorial–tropical area (0–15°S) than in the subtropical–temperate area (south of 15°S) during all seasons. Males predominated in both areas and during all seasons; the exceptions were seasons 2 (April–June) and 3 (July–September) in the equatorial–tropical area and season 2 in the subtropical–temperate area. The sex ratio increased with shark size in the equatorial–tropical area but decreased with size in the subtropical–temperate area. Growth band pairs (including translucent and opaque bands) were counted on images photographed from X‐ray films of vertebrae from the caudal peduncle region. The centrum edge analysis indicated that a growth band pair was formed on the vertebral centrum once per year. Corrected Akaike's information criterion values indicated that the von Bertalanffy growth function (VBGF) provided the best fit to the observed TL‐at‐age data. The likelihood ratio test indicated that the VBGF equations were not significantly different between the sexes. For both sexes combined, VBGF parameters were estimated as follows: asymptotic length was 352.1 cm TL, the Brody growth coefficient was 0.13/year, and the theoretical age at zero length was –1.31 years. Age at first maturity was estimated as 6.5 years for males and 6.7 years for females; theoretical longevity was estimated to be at least 21.4 years.

The age and growth of the blue shark Prionace glauca in the central South Pacific is 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 was formed on the vertebral centrum once per year. The band pairs after the birthmark were counted from 2 to 11 for females and from 2 to 15 for males. 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: for females, theoretical maximum length (L∞) mean±s.d.=330.4±46.6cm TL, growth coefficient k=0.164±0.057year–1 and theoretical age at length 0 (t0)=–1.29±0.78 years; for males, L∞=376.6±32.6cm TL, k=0.128±0.022year–1 and t0=–1.48±0.54 years. The longevities were estimated to be at least 16.8 and 21.6 years for females and males respectively.