| Summary: | 碩士 === 國立臺灣海洋大學 === 環境生物與漁業科學學系 === 94 === Abstract
The reproductive, age and growth, and stomach content of the oceanic whitetip shark, Carcharhinus longimanus, occurred in the northeastern waters off Taiwan were examined in this study. A total of 188（89 females and 99 males）specimens were collected from Nov. 2002 to Jan. 2006 at Nan-fan Ao fish market. The length at birth was estimated to be over 64 cm TL. Sex ratio of embryos was estimated to be 1：1. Males mature at 200.1 cm TL while females are at 194.7 cm TL. This shark is viviparous and with a yolk-sac placenta in reproduction.
The age and growth was estimated using annulus count of caudal vertebra. The annuli were counted up to 12 for female and male, respectivety. The monthly changes of the marginal increment rate （MIR）indicated that translucent and opaque zones on vertebral centra were formed once per year from Jun. to Sep. . The parameters of VBGE obtained by nonlinear regressions based on age and total length were as follows：female L∞ = 323.8 cm TL, K = 0.109 yr-1, t0 = - 0.3722 yr, male L∞ = 334.9 cm TL, K = 0.090 yr-1, t0 = - 1.3563 yr, sexes combined L∞ = 332.3 cm TL, K = 0.095 yr-1, t0 = -1.0937 yr.
The age at sexual maturity are 8.23∼8.65 yrs for females and males, respectivety. Stomach content is comparatively low and scombers and cephalopods are the dominant food items for this species in this study.
|
|---|
