Age and Growth Estimates of the Blacktip Sawtail Catshark Galeus sauteri in Northeastern Waters of Taiwan

Abstract

(n = 884, p < 0.05) for males. Age was determined using band-pair reading of sectioned vertebrae. A single growth band pair (comprising translucent and opaque bands) is formed each year, and up to 14 and 12 band pairs were respectively observed for females and males. An edge analysis indicated that the translucent bands formed from July to Aug. Four growth functions, the traditional von Bertalanffy (VBGF), VBGF with a fixed size-atbirth (L0), Gompertz, and Robertson (logistic) were used to model the observed length-at-age data. The sexspecific growth equations significantly differed. The logistic function had the best fit for both sexes, and the growth parameters including the 95% confidence intervals with a bootstrap method were estimated as follows: asymptotic length L∞ = 48.30 (47.16-49.47) cm TL, and growth coefficient k = 0.374 (0.344-0.402) yr -1 for females, L∞ = 44.29 (42.91-45.88) cm TL and k = 0.392 (0.356-0.429) yr -1 for males. The ages at maturity were respectively estimated to be 9.14 and 7.57 yr for females and males, by substituting the mean sizes at maturity into the Robertson growth equation. Longevities of females and males were respectively estimated to be 20.9 and 12.4 yr. http://zoolstud.sinica.edu.tw/Journals/50.3/284.pdf