| 英文摘要 |
A total of 380, 96 and 112 vertebrae were collected to use on age and growth studies for blue sharks (Prionace glauca) in central and southern Atlantic Ocean, and the oceanic whitetip shark (Carcharhinus longimanus) in Pacific Ocean, respectively. Vertebrae were X-ray radiographed and growth band pairs were read on the films. Growth band pairs were formed annually for both species via marginal increment ratio and edge analysis. Von Bertalanffy growth function was fit in age and total length (TL) data by using SAS software, and parameters were estimated to be Lt=330.9 cm TL, k=0.108 yr-1, t0=-5.775 yrs for the blue shark in central Atlantic Ocean, Lt=305.1 cm TL, k=0.212 yr-1, t0=-0.123 yrs for the blue shark in southern Atlantic Ocean, and Lt=332.3 cm TL, k=0.095 yr-1, t0=-1.094 yrs for the oceanic whitetip shark in Pacific Ocean, respectively. More vertebral samples of the blue shark from southern Atlantic Ocean and smaller specimens, and of the oceanic whitetip shark from far sea fisheries, were needed.
In addition, shark fins-body weight ratios were also accessed in this study. The ratio of the blue shark in Atlantic Ocean was around 5.30% (n=1547; SD=0.57). For Pacific Ocean, the lowest ratio of 4.40% occurred in the pelagic thresher shark (Alopias pelagicus), and the highest ratio of 10.08% was found in the silvertip shark (Carcharhinus albimarginatus). Excluding the shortfin mako (Isurus oxyrinchus) and the scalloped hammerhead (Sphyrna lewini) shark, more ratio data of other species were needed to collect.
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