Résultats de la recherche
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Catch per unit effort (CPUE) data from the early years of commercail krill fishing operations in the Atlantic sector of the Antarctic
does not occur over time for the entire area. High average CPUE were observed in the years 1975/76 and ... discussed as an indicator of krill abundance/biomass and caution is expressed in this regard. Depending on ... are presented from krill fishing operations in CCAMLR Subareas 48.1, 48.2, 48.3 (South Atlantic) for ... years on a subarea and area basis, and between oceanic and shelf regions. Results show that the CPUE may ... and for different years (a to g). (e) Season 1984185 12 10 15 20 25 30 35 40 45 50 55 60 65 ... hours for the split-year (1 July to 30 June); (iii) mean monthly catch/hour for the split-year ... each catch. Statistical tests for year and area differences were carried out using rank methods ... much higher in shelf regions for all three subareas compared to oceanic areas. During this year the ...
Science Journal Paper : CCAMLR Science, Volume 5 (CCAMLR Science, Volume 5) : 31–50 : Auteur(s): Siegel, V., V. Sushin and U. Damm
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Some principles for fisheries regulation from an ecosystem perspective
Paper Title: Some principles for fisheries regulation from an ecosystem perspective Abstract ... regulation of fisheries from an ecosystem perspective, under the Convention for the Conservation of Antarctic ... Marine Living Resources. An important task in this formulation is to derive subsidiary objectives for ... out in the Convention. An important property required for subsidiary objectives is that they are ... the level of catches. On the other hand its simplicity may make it a suitable candidate for an ... principles to be considered in the formulation of a framework for the. regulation of fisheries from an ... ecosystem perspective, under the Convention for the Conservation of Antarctic Marine Living Resources. An ... . An important property required for subsidiary objectives is that they are framed in terms of ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/3 (Selected Scientific Papers, SC-CAMLR-SSP/3) : 323-339 : Auteur(s): de la Mare, W.K.
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An impact assessment framework for bottom fishing methods in the CAMLR Convention Area
Paper Title: An impact assessment framework for bottom fishing methods in the CAMLR Convention ... preliminary assessment of bottom fishing impacts for the 2008/09 toothfish longline fishery. This paper ... illustrates the utility of the standardised approach and provides a methodological template for systematic ... cumulative impact on fragile benthic organisms from bottom fishing activity. The approach has been designed ... for new and explora- tory fisheries in 2008/09 (see New Zealand, 2008). What follows is an outline ... also provide a sound basis on which to complete an ERA in future. Definition of ‘Vulnerable Marine ... , in the New Zealand case, the impact of an anchor falling on the sea floor was assumed to be ... per set, enabling calculation of the anchor footprint on a per-set basis (i.e. two anchors on either ...
Science Journal Paper : CCAMLR Science, Volume 16 (CCAMLR Science, Volume 16) : 195–210 : Auteur(s): Sharp, B.R., S.J. Parker and N. Smith
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Target strengths of krill at 136 and 20 kHz
Paper Title: Target strengths of krill at 136 and 20 kHz Abstract / Description: Estimation of ... . Ensonification of encaged live krill. For aggregations with mean lengths from 45 to 50 mm the mean single-krill ... target strengths range from-68 to-69 dB at 136 kHz. For aggregations with mean lengths from 43 to 47 mm ... the mean single-krill target strengths range from-71 to-77 dB at 20 kHz. Trawl hydroacoustic method ... strengths range from -71 to -77 dB at 20 kRz. Trawl hydroacoustic method. For aggregations with mean ... krill with an average length of 45 to 50 mm, while at a frequency of 20 kHz target strength values of ... -71 to -77 dB were obtained for krill with an average length of 43 to 47 mm. Trawl Hydroacoustic ... Method. At a frequency of 20 kHz mean TS values between -71 and -75 dB were obtained for krill swarms ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/8 (Selected Scientific Papers, SC-CAMLR-SSP/8) : 141–157 : Auteur(s): Kasatkina, S.M.
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Evaluating the impact of multi-year research catch limits on overfished toothfish populations
Paper Title: Evaluating the impact of multi-year research catch limits on overfished toothfish ... additional fisheries removals for research purposes needs to be evaluated against the risk that such catches ... assessed in this study indicate that, where a stock has been depleted to at or below 20% of the median ... should be avoided to ensure that research does not significantly impact on the recovery of depleted ... 30 tonnes per year for 5 years) to assumptions about selectivity (scenarios 7 to 9), size-at ... ch 1.0 0.9 0.8 0.7 0.6 Figure 2: Impact of a 5-year research fishery on recovery 20 years after ... the Southern Ocean (Lack, 2008), was simulated by a constant catch removal each year for 5 years ... an approximately linear response between stock status 20 years after historical over- fishing ceased ...
Science Journal Paper : CCAMLR Science, Volume 18 (CCAMLR Science, Volume 18) : 47–55 : Auteur(s): Welsford, D.C
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Notes on the use of virtual population analysis for stock assessment of the mackerel icefish, Champsocephalus gunnari (Lönnberg, 1906) in Subarea 48.3 for the 1990/91 and 1991/92 seasons
Paper Title: Notes on the use of virtual population analysis for stock assessment of the mackerel ... techniques, from 1991 back to 1977. The predicted age structure, dominated in recent years by the 1987 year ... proportion of 5 year olds, which was not observed during the survey on Falklands Protector in January 1992 ... icefish, Champsocephalus gunnari (Lönnberg, 1906) in Subarea 48.3 for the 1990/91 and 1991/92 seasons ... biomass of 5 year olds predicted by the VPA for 1991/92 might be an artefact of the analysis. In the ... the most recent year, and hence no terminal Fs for the VPA. This report presents notes on a reworking ... ). Annual recruitment, R was generated independently for each year on each run as follows: where R = mean ... distribution estimated by the VPA for that year (Figure 1). Concern was expressed at WG-FSA-91 that the large ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/9 (Selected Scientific Papers, SC-CAMLR-SSP/9) : 49–79 : Auteur(s): Parkes, G.
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Estimation of natural mortality using catch-at-age and aged mark-recapture data: a multi-cohort simulation study comparing estimation for a model based on the Baranov equations versus a new mortality equation.
obtained by integrating an ordinary differential equation (ODE) for within-year population dynamics. The ... new mortality equation. Abstract / Description: An estimation strategy for natural mortality, M ... applied. Two alternative estimation models were developed both using a Poisson likelihood for annual ... population. Estimation for the BODE model requires an extra component to the log-likelihood which defines the ... obtained by integrating an ordinary differential equation (ODE) for within-year population dynamics. The ... ) model) uses an ODE with constant within-year catch per unit time for each age class, and as a result ... of the population size for each age class and year of fishing. Allowing an adequate time for mixing ... time. The initial age structure at the first year of fishing and for subsequent years is obtained by ...
Science Journal Paper : CCAMLR Science, Volume 18 (CCAMLR Science, Volume 18) : 1–27 : Auteur(s): Candy, S.G.
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Intra-annual variability in the density of Antarctic krill (Euphausia superba) at South Georgia, 2002–2005: within-year variation provides a new framework for interpreting previous ‘annual’ estimates of krill density
the regression-predicted within-year variation. Years that stand out for markedly low krill density ... South Georgia, 2002–2005: within-year variation provides a new framework for interpreting previous ... -year’ variation could simply be attributed to sampling on different dates of the year (e.g. November cf ... g m –2, SD = 24.3), but had risen substantially by summer in each year (mean = 89.5 g m –2, SD ... -predicted within-year variation. Years that stand out for markedly low krill density (i.e. densities below ... management (Everson, 1992) and for understanding change on an interannual scale. Moored instrument arrays ... time-series of krill density at 30-minute intervals for both the on- shelf and off-shelf mooring. For ... ) AT SOUTH GEORGIA, 2002–2005: WITHIN-YEAR VARIATION PROVIDES A NEW FRAMEWORK FOR INTERPRETING ...
Science Journal Paper : CCAMLR Science, Volume 14 (CCAMLR Science, Volume 14) : 27–41 : Auteur(s): Saunders, R.A., A.S. Brierley, J.L. Watkins, K. Reid, E.J. Murphy, P. Enderlein and D.G. Bone
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Estimating the impact of depredation by killer whales and sperm whales on longline fishing for toothfish (Dissostichus eleginoides) around South Georgia
and 4 animals, and have a relatively lower impact on catches, depressing CPUE by up to 20%. Sperm ... fishing for toothfish (Dissostichus eleginoides) around South Georgia Abstract / Description: Observer ... between months. Both species demonstrate an east to west migration throughout the season that is not ... cetaceans, accounting for other determinants of toothfish CPUE through a generalised linear model, it is ... types were killer whales, sperm whales and both species. An overall correction factor for the year can ... over the years 2003 to 2006, followed by two years of low interaction, and finally another year of ... , followed by two years of low interaction, and finally another year of very high interaction in 20009. The ... must decide how to account for what can be considered an unattributed source of fishery-related ...
Science Journal Paper : CCAMLR Science, Volume 17 (CCAMLR Science, Volume 17) : 163–178 : Auteur(s): Moir Clark, J. and D.J. Agnew
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Some thoughts on precautionary measures for the krill fishery
Paper Title: Some thoughts on precautionary measures for the krill fishery Abstract / Description ... : The concept of precautionary measures for krill is discussed. A precautionary catch limit, based on ... (WG-Krill) is discussed and it is concluded that such a method is appropriate in setting an overall ... refinement to provide a sufficient safeguard for land-based predators. A new approach is described which ... spawning biomass dropping below 20% of its pre-exploitation median level over a 20-year harvesting period ... is 10%; and the median krill escapement1 in the spawning biomass over a 20-year period is 75% of ... limited region close to predator colonies. Arising from this concern has been a quest for an equable way ... within Subarea 48.3, and we take this as an example to develop ideas for incorporating the requirements ...
Science Journal Paper : CCAMLR Science, Volume 3 (CCAMLR Science, Volume 3) : 1–11 : Auteur(s): Everson, I. and W.K. de la Mare