Age and Growth of the Spot-Tail Shark, Carcharhinus sorrah, in the Taiwan Strait

Abstract

The age and growth of the spot-tail shark, Carcharhinus sorrah, were estimated based on 327 specimens (171 females and 156 males) captured by the coastal/offshore longline or drift net fishery in the waters of the Taiwan Strait from October 2010 to December 2011 and July 2019 to August 2021. Sex-specific whole weight (W)-curved total length (TL) relationships were estimated as follows: W = 7.0 x 10(-6) TL2.9313 (n = 171, and p < 0.05) for females, and W = 4.0 x 10(-6) TL3.0516 (n = 156, and p < 0.05) for males. The periodicity of growth band pair (including translucent and opaque bands) deposition in precaudal vertebrae was assumed to be 1 year based on centrum edge analysis and verified by a statistical analysis. The band pairs after the birth mark were counted as 0-5 and 0-8 for females and males, respectively. The Gompertz and von Bertalanffy growth function best described the observed length-at-age data for females and males, respectively. The parameters for sex-specific growth equations were estimated as: L-infinity = 158.6 +/- 9.09 cm TL, k(G) = 0.2347 +/- 0.0245 year(-1), and c = -0.3233 +/- 0.2043 (n = 171, and p < 0.01) for females, and L-infinity = 170.2 +/- 9.51 cm TL, k = 0.1461 +/- 0.0182 year(-1), and t(0) = -3.1586 +/- 0.2065 (n = 156, and p < 0.01) for males.