Changes in baseline growth and maturation parameters of Northwest Atlantic porbeagle, <i>Lamna nasus</i>, following heavy exploitation

Cassoff, Rachel M.; Campana, Steven E.; Myklevoll, Sigmund

doi:10.1139/f06-167

Cited by 33 publications

(29 citation statements)

References 30 publications

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“…Density-mediated changes in life history parameters have been reported for four other shark species following extended exploitation. In the northwestern Atlantic, changes in both the growth rate and age at maturation were observed in the porbeagle (Cassoff et al 2007). Evidence of change in the growth rate of juvenile sandbar sharks has also been reported (Sminkey and Musick 1995).…”

Section: Discussionmentioning

confidence: 99%

Validated age and growth estimates for Carcharhinus obscurus in the northwestern Atlantic Ocean, with pre- and post management growth comparisons

Natanson

Gervelis

Winton³

et al. 2013

Environ Biol Fish

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Age and growth estimates for the dusky shark, Carcharhinus obscurus, were derived from vertebral centra collected in the northwestern Atlantic Ocean. Sample collection spanned the years prior to and following the implementation of management measures . Growth was compared pre-and post-population depletion and pre-and post-management to investigate the possibility of density-mediated shifts in age and growth parameters over time. There was no evidence of difference between periods for either sex. Additionally, bomb radiocarbon dating was used to determine the periodicity of band pair formation. Results support the traditional interpretation of annual band pairs up to approximately 11 years of age. After this time, vertebral counts considerably underestimate true age. Maximum validated ages were estimated to be between 38 and 42 years of age (an increase of 15 to 19 years over the band count estimates), confirming longevity to at least 42 years of age. Growth curves estimated using only validated data were compared to those generated using band pair counts. Logistic growth parameters derived from validated vertebral length-at-age data were L ∞ = 261.5 cm FL, L o =85.5 cm, t o =4.89 year and g= 0.15 year −1 for the sexes combined. Revised estimates of age at maturity were 17.4 years for males and 17.6 years for females.

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Section: Discussionmentioning

confidence: 99%

Validated age and growth estimates for Carcharhinus obscurus in the northwestern Atlantic Ocean, with pre- and post management growth comparisons

Natanson

Gervelis

Winton³

et al. 2013

Environ Biol Fish

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“…The porbeagle shark, Lamna nasus, in the family Lamnidae, which includes the white shark, exhibits different life-history traits between New Zealand and North Atlantic populations, and between virgin and exploited populations in the western North Atlantic (Cassoff et al 2007;Francis et al 2007). As white sharks inhabit many waters of the world's oceans, being found in diverse and changing habitats, we hypothesised that the lifehistory traits of Japanese white sharks would differ from those of other populations.…”

Section: Introductionmentioning

confidence: 99%

Age, growth and genetic status of the white shark (Carcharodon carcharias) from Kashima-nada, Japan

Tanaka¹,

Kitamura²,

Mochizuki³

et al. 2011

Mar. Freshwater Res.

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Abstract. The white shark, a top predator inhabiting the world's oceans, is an endangered species. However, knowledge of its life-history traits and population structure is still limited. We hypothesised that life-history traits would vary among populations because the species' various habitats are diverse and change through time. Age was estimated by counting growth bands in the centra of white sharks caught in Japan. The von Bertalanffy growth parameters were estimated at L N ¼ 455 cm TL, k ¼ 0.196 year À1 and t 0 ¼ À1.92 years for males and L N ¼ 607 cm TL, k ¼ 0.159 year À1 and t 0 ¼ À1.80 years for females. The growth rate to maturity was higher than that known for individuals from California and South Africa. Male sharks matured at 310 cm TL at 4 years of age and females began to mature at ,450 cm TL and 7 years. The D-loop-region sequences of mitochondrial DNA extracted from Japanese white sharks and GenBank datasets from sharks of California, Australia, New Zealand and South Africa indicate that Japanese white sharks form a monophyletic clade separate from the populations of other regions. The results suggest that unique life-history traits of Japanese white sharks may be caused by genetic differences.

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“…It is not possible to establish the exact number of bands because no thin sections of vertebral centra could be prepared. Nevertheless, our results suggest that this specimen of Carcharomodus escheri was more than 10 years old representing a late subadult to adult individual in comparison to living lamnid sharks (compare, e.g., Fowler et al 2005;Goldman and Musick 2006;Cassoff et al 2007). …”

Section: Terminology This Tooth Corresponds To the Intrabullar Intermentioning

confidence: 62%

Exceptional preservation of the white sharkCarcharodon(Lamniformes, Lamnidae) from the early Pliocene of Peru

Ehret¹,

Hubbell²,

MacFadden

2009

Journal of Vertebrate Paleontology

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Changes in baseline growth and maturation parameters of Northwest Atlantic porbeagle, Lamna nasus, following heavy exploitation

Cited by 33 publications

References 30 publications

Validated age and growth estimates for Carcharhinus obscurus in the northwestern Atlantic Ocean, with pre- and post management growth comparisons

Validated age and growth estimates for Carcharhinus obscurus in the northwestern Atlantic Ocean, with pre- and post management growth comparisons

Age, growth and genetic status of the white shark (Carcharodon carcharias) from Kashima-nada, Japan

Exceptional preservation of the white sharkCarcharodon(Lamniformes, Lamnidae) from the early Pliocene of Peru

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