Age Determination of an Elasmobranch (<i>Squalus acanthias</i>) by X-ray Spectrometry

Jones, Barry C.; Geen, G. H.

doi:10.1139/f77-005

Cited by 44 publications

(34 citation statements)

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“…), so caution should be used when using age data. Other methods of ageing S. acanthias include x-ray spectrometry (Jones and Geen, 1977a) and the size of the eye lens (Siezen, 1989). The observed maximum sizes of male and female S. acanthias, reviewed by Ketchen (1972), were 100 and 135cm (Northwest Pacific), 107 and 130 cm (Northeast Pacific), 86 and 108 cm (Northwest Atlantic) and 83 and 110 cm (Northeast Atlantic).…”

Section: Life-historymentioning

confidence: 99%

Bayesian Assessment of Northeast Atlantic Spurdog Using a Stock Production Model, with Prior for Intrinsic Population Growth Rate Set by Demographic Methods

Hammond¹,

Ellis²

2004

J. Northw. Atl. Fish. Sci.

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Schaefer-model stock assessments can be imprecise when they are fitted to catch rate data (CPUE) because a large, unproductive stock can often explain CPUE trends as well as a small, productive one. However, consideration of life-history characteristics can improve parameter estimates by constraining maximum productivity. Therefore, we applied the methods of McAllister et al. (2001) to Northeast Atlantic spurdog (Squalus acanthias) by using demographic techniques to convert prior distributions for age-specific fecundity and natural mortality (the latter based on published estimates from tagging studies) to prior distributions for the intrinsic rate of population growth (r). The priors for r generated in this manner were then used in a Bayesian, Schaefer-model assessment of spurdog, fitted to bottom trawl survey CPUE data. Results suggest the stock is depleted to about 5% of virgin biomass.

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Section: Life-historymentioning

confidence: 99%

Bayesian Assessment of Northeast Atlantic Spurdog Using a Stock Production Model, with Prior for Intrinsic Population Growth Rate Set by Demographic Methods

Hammond¹,

Ellis²

2004

J. Northw. Atl. Fish. Sci.

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“…The age of an elasmobranch could be as sessed by measuring the variation in the com position of different elements within verte brae by X-ray spectrometry technique [35], In another technique of making replicas, polyvinyl alcohol solution is first applied on the clean centrum of vertebra. The film is then peeled off after drying and then mounted between a pair of slides for observations.…”

Section: Vertebraementioning

confidence: 99%

“…In the absence of a drastic seasonal differ ence between summer and winter, the occur rence of yearly marking in hard parts was ini tially doubted in tropical species [ 83], The strain of migration in the immature, cessation of feeding following maturation and the spawning stress in the matured individuals are the causes of growth check formation in Silonia childrenii [29], Spawning in the female and oral gestation in the male may be the causes of ring formation in marine catfishes [35], A spawning ring due to metabolic strain associated with matura tion and spawning and a winter ring due to reduced temperature and feeding were re ported to occur each year in scales of threadfin bream [ 10].…”

Section: Causes Of Ring Formationmentioning

confidence: 99%

Age Determination and Longevity in Fishes

Das¹

1994

Gerontology

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It is possible to determine the age of fishes with reasonable accuracy by reading the ‘growth rings’ (annuli) in hard parts (scale, otolith, opercular bone, vertebra and cross-section of dorsal or pectoral spine and fin rays). Primary growth increments in ‘otoliths’ can also be used as an alternative method of age determination. The traditional methods could be supplemented with more reliable fmorochrome and microradio-graphic techniques. The suitability of the use of hard parts and the techniques may vary among the species. It is essential that the ‘true rings’ be distinguished from other types of rings, such as false rings, larval rings and spawning rings through repeated examination of samples to avoid confusion and inaccuracy in age determination. The causes and the periodicity of ring formation may vary from species to species. The growth history of fishes could be traced by back calculation of length attained at different ages. Among the different types of growth equations, the Von Bertalanffy’s model appears to be the most suitable for fishes of both temperate and tropical regions. With slight modification, the same model may also serve to estimate the maximum theoretical calculated age (longevity) of fishes. The longevity of fishes show wide variations. The life-span may be short, intermediate and long. Whereas the lowest range of life-span (1-2 years) is exhibited by some species of lampreys and teleosts, there are species of dogfishes, sturgeons, paddlefishes, rockfishes and eels which have the life-span (70-152 years) in the highest range. A number of factors (size, sex, temperature, diet, reproduction, age at maturity and genetic composition) are believed to influence the longevity of fishes.

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“…Some examples are: X-radiography (e.g., Natanson and Cailliet 1990;), X-ray spectrometry (Jones and Green 1977), cedarwood oil immersion (Neer and Cailliet 2001), alizarin red (LaMarca 1966), silver nitrate (e.g., Neer andCailliet 2001), crystal violet (e.g. Johnson 1979), graphite microtopography (Neer and Cailliet 2001) and the use of copper-, lead-and iron-based salts (e.g., Gelsleichter et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Age and growth of the bigeye thresher shark,Alopias superciliosus, from the pelagic longline fisheries in the tropical northeastern Atlantic Ocean, determined by vertebral band counts

Fernandez‐Carvalho

Coelho

Erzini

et al. 2011

Aquat. Living Resour.

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-The bigeye thresher, Alopias supercilious, is commonly caught as bycatch in pelagic longline fisheries targeting swordfish. Little information is yet available on the biology of this species, however. As part of an ongoing study, observers sent aboard fishing vessels have been collecting set of information that includes samples of vertebrae, with the aim of investigating age and growth of A. supercilious. A total of 117 specimens were sampled between September 2008 and October 2009 in the tropical northeastern Atlantic, with specimens ranging from 101 to 242 cm fork length (FL) (176 to 407 cm total length). The A. supercilious vertebrae were generally difficult to read, mainly because they were poorly calcified, which is typical of Lamniformes sharks. Preliminary trials were carried out to determine the most efficient band enhancement technique for this species, in which crystal violet section staining was found to be the best methodology. Estimated ages in this sample ranged from 2 to 22 years for females and 1 to 17 years for males. A version of the von Bertalanffy growth model (VBGF) re-parameterised to estimate L 0 , and a modified VBGF using a fixed L 0 were fitted to the data. The Akaike information criterion (AIC) was used to compare these models. The VBGF produced the best results, with the following parameters: L inf = 293 cm FL, k = 0.06 y -1 and L 0 = 111 cm FL for females; L inf = 206 cm FL, k = 0.18 y -1 and L 0 = 93 cm FL for males. The estimated growth coefficients confirm that A. supercilious is a slow-growing species, highlighting its vulnerability to fishing pressure. It is therefore urgent to carry out more biological research to inform fishery managers more adequately and address conservation issues.

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Age Determination of an Elasmobranch (Squalus acanthias) by X-ray Spectrometry

Abstract: Ages of spiny dogfish (Squalus acanthias) in the Strait of Georgia, B.C., have been estimated by an X-ray spectrometric technique which involves measuring variations in the element composition within vertebrae.

Cited by 44 publications

References 0 publications

Bayesian Assessment of Northeast Atlantic Spurdog Using a Stock Production Model, with Prior for Intrinsic Population Growth Rate Set by Demographic Methods

Bayesian Assessment of Northeast Atlantic Spurdog Using a Stock Production Model, with Prior for Intrinsic Population Growth Rate Set by Demographic Methods

Age Determination and Longevity in Fishes

Age and growth of the bigeye thresher shark,Alopias superciliosus, from the pelagic longline fisheries in the tropical northeastern Atlantic Ocean, determined by vertebral band counts

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