Age and growth estimates of the blue shark Prionace glauca in the central South Pacific Ocean

The age and growth of the blue shark Prionace glauca in the central South Pacific is described based on 267 specimens that were collected by scientific observers on board Taiwanese large-scale tuna longline fleets between May 2009 and May 2011. Growth band pairs (identified as translucent and opaque bands) were counted on images photographed from X-ray films of the vertebrae from the caudal peduncle region. The marginal increment ratio and centrum edge analysis indicated that a growth band pair was formed on the vertebral centrum once per year. The band pairs after the birthmark were counted from 2 to 11 for females and from 2 to 15 for males. The bias corrected Akaike information criterion indicated that the von Bertalanffy growth function (VBGF) best fitted the observed total length (TL)-at-age data. The parameters of sex-specific VBGF were estimated as follows: for females, theoretical maximum length (L∞) mean±s.d.=330.4±46.6cm TL, growth coefficient k=0.164±0.057year–1 and theoretical age at length 0 (t0)=–1.29±0.78 years; for males, L∞=376.6±32.6cm TL, k=0.128±0.022year–1 and t0=–1.48±0.54 years. The longevities were estimated to be at least 16.8 and 21.6 years for females and males respectively.

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AGE AND GROWTH OF THE BLUE SHARK PRIONACE GLAUCA IN THE EASTERN ATLANTIC OCEAN

KSTU News ◽

10.46845/1997-3071-2021-62-11-25 ◽

2021 ◽

pp. 11-25

Author(s):

Beraki Weldegiorgish Teklekhaimanot ◽

Sergey Vadimovich Shibaev ◽

Sergey Yurievich Gulyugin

Keyword(s):

Atlantic Ocean ◽

Growth Parameters ◽

Growth Function ◽

Age And Growth ◽

Growth Band ◽

Prionace Glauca ◽

Western Africa ◽

Eastern Atlantic Ocean ◽

Digital Microscope ◽

Central Atlantic

In this study, 292 blue sharks Prionace glauca (Linnaeus, 1758) (from 151 to 305 cm total length, TL) were collected off western Africa in the eastern central Atlantic Ocean between 1980 and 1982. Vertebral sections of females specimens ranged from 175 to 300 cm and males specimens ranged from 166 to 312 cm TL were processed and analyzed for age and growth parameters. Growth band pairs (translucent and opaque bands) were counted on the images photographed from the stained whole vertebrae using digital microscope called Digi Scope II. The band pairs after the birthmark were counted from 3 to 12 for males and from 4 to 13 for females. Growth parameters were derived using the Von Bertalanffy growth function (VBGF) based on FISAT and solver solution Microsoft excel and Ford Wall-Ford. VBGF was that which best fit the data. Parameters derived from the combination of observed and back-calculated lengths, K = 0.1, L_∞ = 386.4 cm and t_0 = −1.35 year for males and K = 0.12 year -1, L_∞= 355 cm and t_0 = –1.02 year for females were considered to best describe growth. The longevity was estimated to be at least 23.7 and 28.3 years for females and males respectively. The natural mortality rate was estimated to be 0.15 year - 1 and 0.18 year -1 for males and females respectively.

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Age and growth estimates of the Kwangtung skate Dipturus kwangtungensis in the waters of northern Taiwan

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315415001307 ◽

2015 ◽

Vol 96 (7) ◽

pp. 1395-1402 ◽

Cited By ~ 1

Author(s):

Shoou-Jeng Joung ◽

Chien-Chi Chen ◽

Kwang-Ming Liu ◽

Tzu-Chi Hsieh

Keyword(s):

Growth Parameters ◽

Information Criterion ◽

Growth Function ◽

Age And Growth ◽

Gompertz Function ◽

Growth Band ◽

Von Bertalanffy Growth Function ◽

North Eastern ◽

Robertson Function ◽

Northern Taiwan

The age and growth of Kwangtung skate, Dipturus kwangtungensis, in the waters off northern Taiwan were estimated from 422 specimens collected between July 2006 and July 2008 at the Tashi fishing market in north-eastern Taiwan. The sexes-combined relationship between total length (TL) and centrum diameter (D) was estimated as follows: TL = 14.11D0.888 (N = 411, r2 = 0.94, P < 0.001). Growth band pairs (comprised of translucent and opaque bands) in vertebrae were determined to form once annually, based on the centrum edge analysis. Up to 14 band pairs were found for both sexes. The von Bertalanffy growth function (VBGF), two-parameter VBGF, the Robertson function, and the Gompertz function were used to fit the observed length-at-age data. The Akaike information criterion corrected indicated that the Gompertz function best fit the observed length at age data. Sex-specific growth functions were not significantly different; the sexes-combined growth parameters were estimated as follows: asymptotic length (L∞) = 96.7 cm TL, growth coefficient (kG) = 0.144 year−1 and constant (t0) = 5.45 year (N = 364, P < 0.01).

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