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Title: Age and Growth of the Scalloped Hammerhead, Sphyrna lewini, in Northeastern Taiwan Waters 
Author: Chen, CT; Leu, TC; Joung, SJ; Lo, NCH
Date: 1990-04
Publisher: University of Hawaii Press
Citation: Chen CT, Leu TC, Joung SJ, Lo NCH. 1990. Age and growth of the scalloped hammerhead, Sphyrna lewini, in northeastern Taiwan waters. Pac Sci 44(2): 156-170.
Abstract: Age and growth of the scalloped hammerhead, Sphyrna lewini,
caught mostly by longline and harpoon in northeastern Taiwan waters from
December 1984 to November 1985, were determined from annulus counts from
325 individuals. Translucent and opaque zones on vertebral centra were formed
twice a year, in June and December. The von Bertalanffy growth curve parameters
obtained using a nonlinear regression based on age and observed length
were as follows: asymptotic length (Loo) = 319.72 cm total length (TL), growth
coefficient (K) = 0.249, age at zero length (to) = - 0.413 yr for females; and
Loo = 320.59 cm TL, K = 0.222, to = - 0.746 yr for males. Growth was apparently
fast and varied among individuals. Growth rate s for females were estimated
to be 63cm for the first year, 23-50 cm/yr for years 2-5, and 3-19 cm/yr for years
6-13. Growth rates for males was 54 cm for the first year, 22-42 cm/yr for years
2-5, and 11-18 cm/yr for years 6-8. Holden's method was applied to estimate
growth parameters for purposes of comparison. Estimated age at maturity was
4.lyr (210cmTL) for females and-3:8yr (198cm-TL) for males, based on the von
Bertalanffy growth equation from back-calculated data. The largest female (331
cm TL) whose age was determined in this study was 14.0 yr old; the largest male
(301 cm TL) was 10.6 yr old.
ISSN: 0030-8870
URI: http://hdl.handle.net/10125/1267

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