Age, growth, and reproduction of silky sharks, Carcharhinus falciformis, in northeastern Taiwan waters

To examine the age, growth and reproduction of silky sharks, Carcharhinus falciformis, in the waters off northeastern Taiwan, 469 specimens (213 females and 256 males) were collected from August 2000 to January 2002 at the Nanfanao fish market, northeastern Taiwan. The relationship between body weig...

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Bibliographic Details
Published in:Fisheries research 2008-04, Vol.90 (1), p.78-85
Main Authors: Joung, Shoou-Jeng, Chen, Che-Tsung, Lee, Hsian-Hau, Liu, Kwang-Ming
Format: Article
Language:English
Subjects:
Age and growth
Agnatha. Pisces
Animal, plant and microbial ecology
Applied ecology
Biological and medical sciences
Carcharhinus falciformis
Exploitation and management of natural biological resources (hunting, fishing and exploited populations survey, etc.)
Fundamental and applied biological sciences. Psychology
Marine
Reproduction
Silky shark
Taiwan
Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
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Summary:To examine the age, growth and reproduction of silky sharks, Carcharhinus falciformis, in the waters off northeastern Taiwan, 469 specimens (213 females and 256 males) were collected from August 2000 to January 2002 at the Nanfanao fish market, northeastern Taiwan. The relationship between body weight ( W) and total length (TL) for both sexes combined was expressed as: W = 2.92 × 10 −6 TL 3.15 ( n = 469, p < 0.01). The relationship between TL and vertebral centrum radius ( R) for both sexes combined data was estimated as: TL = 25.979 + 18.197 R ( n = 250, p < 0.01). Growth bands (including translucent and opaque zones) in precaudal vertebrae formed once a year between December and January and were counted up to 11 and 14 for females and males, respectively. The von Bertalanffy growth function (VBGF) was used to model the observed length at age data. The sexes combined VBGF predicted an asymptotic length ( L ∞) = 332.0 cm TL, growth coefficient ( k) = 0.0838 year −1, age at zero length ( t 0) = −2.761 year ( n = 250, p < 0.01). Size at 50% maturity for males was estimated to be 212.5 cm based on the logistic curve, which corresponded to 9.3 years. Females matured at 210–220 cm, which correspond to 9.2–10.2 years. The length at birth was estimated to be 63.5–75.5 cm TL. The number of embryos per litter was 8–10 and sex ratio of embryos was 1:1.
ISSN:0165-7836
1872-6763
DOI:10.1016/j.fishres.2007.09.025