Résultats de la recherche
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A comparison between otoliths and scales for use in estimating the age of Dissostichus eleginoides from South Georgia
Paper Title: A comparison between otoliths and scales for use in estimating the age of ... result in large errors in age data for long-lived species, usually due to compression of scale circuli ... otoliths and scales give the same age estimates, and compared the precision of age estimation for both ... Dissostichus eleginoides from South Georgia Abstract / Description: Age composition is fundamental to ... . Sustainable exploitation rates should have been 20-30% of that based on age determinations from scales, in ... use of otoliths and scales in estimating tootlifish age 0 10 20 30 40 50 10 20 30 40 50 Reader l ... suckers grew quickly at ages 4-7 years, few surviving beyond an age of 9 years. Annual mortality was ... using scales than otoliths. There was evidence that for fish older t l~an 16 years (estimated using ...
Science Journal Paper : CCAMLR Science, Volume 8 (CCAMLR Science, Volume 8) : 75–92 : Auteur(s): Ashford, J.R., S. Wischniowski, C. Jones, S. Bobko and I. Everson
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Direct ageing of Antarctic krill (Euphausia superba) – potential utility of eyestalk sections for age determination
Abstract: We outline a method for the direct determination of age in Antarctic krill (Euphausia ... seasons. Marks consistent with annuli observed in laboratory raised krill were observed. Length at age ... ) and fall on the line for two and three year old krill. If validated, the technique should allow the ... development of age-based assessments of krill necessary for management. Further because the annular bands ...
Meeting Document : WG-EMM-15/45 : Auteur(s): C. Reiss (USA), R. Kilada (Canada) and S. Kawaguchi (Australia)
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Age-length key for Champsocephalus gunnari from Subarea 48.3, Dr Eduardo Holmberg survey, February/March 1994
Abstract: An age-length key was prepared for Champsocephalus gunnari from the Subarea 48.3, based ... Rocks, a large concentration of fish belonging to age groups 2 (90%) and 3 (10%) was found. The length ... and, the mean lengths of age groups 1-2. Such correspondence was also obtained for age group 3 when ... , E. Marschoff and R. Casaux (Argentina) Title: Age-length key for Champsocephalus gunnari from ...
Meeting Document : WG-FSA-94/11 : Auteur(s): E. Barrera-Oro, E. Marschoff and R. Casaux (Argentina)
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Methods of age determination for mackerel icefish (Champsocephalus gunnari Lönnberg 1905) from the South Georgia Island shelf
age assessments of fish longer than 30 cm having an enlarged otolith centre. An age/length key for the ... Paper Title: Methods of age determination for mackerel icefish (Champsocephalus gunnari Lönnberg ... taken in the period July to September. The latter was done using specimens from strictly defined age ... third quarter of the year was also calculated. File: 04-Frolkina.pdf ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/6 (Selected Scientific Papers, SC-CAMLR-SSP/6) : 37–49 : Auteur(s): Frolkina, Zh.A.
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Estimation of natural mortality using catch-at-age and aged mark-recapture data: a simulation study comparing estimation for a model based on the Baranov equations versus a new mortality equation
the age-structured population for each fishing year by annual recursive use of difference equations ... . An alternative estimation strategy was tested using simulation whereby catch-at-age and aged mark ... R. Both use the same Poisson likelihood for annual number of recaptures by age class, and both model ... for population numbers at age obtained by integrating a first order ordinary differential equation ...
Meeting Document : WG-SAM-10/11 Rev. 1 : Auteur(s): S.G. Candy (Australia)
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Comparison of estimators of effective sample size for catch-at-age and catch-at-length data using simulated data from the Dirichlet-multinomial Distribution
stocks. An appropriate and accurate estimate of the ESS for catch frequency data for each fishery and ... fishing year is therefore important for such assessments and this issue is studied using simulation ... parameter. This last method generally gave the best estimator of an ESS that is appropriate for haul-level ... one of the year-level methods gave reduced estimates of ESS. An appropriate distributional model that ...
Meeting Document : WG-SAM-07/7 : Auteur(s): S.G. Candy (Australia)
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Estimation of natural mortality for the Patagonian toothfish at Heard and McDonald Islands using catch-at-age and aged mark-recapture data from the main trawl ground
were obtained using proportions-at-length and fishery and year specific age length keys (ALKs) for ... . An alternative strategy was adopted whereby the catch-at-age and mark-recapture data were restricted ... releases and recaptures of tagged fish were available. Catch and releases by age class for this fishery ... programmed in R, based on alternative ordinary differential equations (ODE) for within-year population ...
Meeting Document : WG-FSA-10/41 : Auteur(s): S. Candy, D. Welsford, T. Lamb, J. Verdouw and J. Hutchins (Australia)
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Age-structured production model for toothfish at South Georgia
model. Revisions to the selectivity model this year have led to an ASPM with superior performance ... was fitted for all years, the change to the new selectivity function improved the fit to length ... decaying function of age, with three easily interpretable parameters. When only a single selectivity curve ... frequency data achieved last year, but the fit was still poor. The fit to the CPUE was also poor. With ...
Meeting Document : WG-FSA-SAM-05/18 : Auteur(s): A. Payne, G.P. Kirkwood, R. Hillary and D.J. Agnew (United Kingdom)
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Comparison of age- and length-based harvest control rules for the South Georgia icefish (Champsocephalus gunnari) fishery
age vector for the population. An age-based harvest control rule was then applied using the operating ... Abstract: An age-based operating model was constructed and used to derive an initial numbers at ... (United Kingdom) Title: Comparison of age- and length-based harvest control rules for the South Georgia ... model dynamics and assuming perfect knowledge of the resource (initial numbers at age, maturity and ...
Meeting Document : WG-SAM-10/12 : Auteur(s): C.T.T. Edwards, R.M. Hillary, R.E. Mitchell and D.J. Agnew (United Kingdom)
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A von Bertalanffy growth model for Division 58.5.2 fitted to length-at-age data and a comparison of predicted with observed growth from mark–recapture data
Abstract: Length-at-age data for the Patagonian toothfish (Dissostichus eleginoides) caught by ... weighted least squares (IWLS) substantially under-predicted mean length-at-age for older ages compared to ... -age for young fish. Author(s): S.G. Candy, A.J. Constable, T. Lamb and R. Williams (Australia) Title ... : A von Bertalanffy growth model for Division 58.5.2 fitted to length-at-age data and a comparison of ...
Meeting Document : WG-FSA-SAM-06/07 : Auteur(s): S.G. Candy, A.J. Constable, T. Lamb and R. Williams (Australia)