Résultats de la recherche
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Factors that may influence the accuracy of abundance estimates from CCAMLR tag-recapture programs for Dissostichus spp. and best practice for addressing bias
spatially explicit modelling approaches is also an important next step for Dissostichus spp. assessments ... -recapture programs for Dissostichus spp. and best practice for addressing bias Abstract / Description: The ... Lincoln-Petersen equation, the simplest form of an abundance estimator using tag-recapture data, was used ... account for their effects in stock assessments for Dissostichus spp. are also summarised. In nearly all ... (see review by Polacheck et al., 2010). For exam- ple, stock assessment model frameworks such as CASAL ... = ´ . (2) Deriving an accurate value for N using this esti- mator is based on a variety of assumptions ... ; SC-CAMLR, 2011a, 2011b). In inte- grated assessments for South Georgia and the Ross Sea, an estimate ... for depredation on tagged fish that may have occurred, however, we are unaware of such an adjustment ...
Science Journal Paper : CCAMLR Science, Volume 20 (CCAMLR Science, Volume 20) : 63–72 : Auteur(s): Welsford, D.C. and P.E. Ziegler
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Alternative methods for determining subarea or local area catch limits for krill in Statistical Area 48
current fishing patterns; and (vi) the potential for delay in implementing the alternative. An alternative ... Paper Title: Alternative methods for determining subarea or local area catch limits for krill in ... precautionary catch limit on krill (Euphausia superba) in Statistical Area 48. The measure also implies an ... relationships between krill and their predators are explicitly considered and the potential for delayed ... single year. Then, for the following two years, that subarea would be closed to fishing. For example, if ... patterns; and (vi) the potential for delay in implementing the alternative. An alternative is less likely ... not an acceptable, long-term strategy for managing the krill fishery (SC-CAMLR, 1991). Considering ... ecosystem. There will be an initial cost to collect the data necessary for defining the impacts to ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/9 (Selected Scientific Papers, SC-CAMLR-SSP/9) : 237–249 : Auteur(s): Watters, G. and R.P. Hewitt
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Joinville–D’Urville Islands (Subarea 48.1) – a former fishing ground for the spiny icefish (Chaenodraco wilsoni), at the tip of the Antarctic Peninsula – revisited
Paper Title: Joinville–D’Urville Islands (Subarea 48.1) – a former fishing ground for the spiny ... depths of 149 to 282 m on 21 February 2002. Published and unpublished reports from fishing operations in ... , sparse, being restricted to the two seasons (1978/79 and 1979/80) when Polish and GDR vessels fished in ... the southern Scotia Arc region – a review and pro spects for future research. Rev. Fish Res. (in ... Joinville–D’Urville Islands for the fi rst time (Figure 1). The authors took this opportunity to review ... avail- able for two seasons, 1978/79 and 1979/80. Polish Kock et al. 4 and GDR vessels fi shed ... . Catches were variable between months, as can be seen from total catch fi gures pro- vided by month for ...
Science Journal Paper : CCAMLR Science, Volume 11 (CCAMLR Science, Volume 11) : 1–20 : Auteur(s): Kock, K.-H., L. Pshenichnov, C.D. Jones, K. Shust, K.E. Skora and Zh.A. Frolkina
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Length-based assessment for mackerel icefish (Champsocephalus gunnari) at South Georgia
Paper Title: Length-based assessment for mackerel icefish (Champsocephalus gunnari) at South ... Georgia Abstract / Description: The current CCAMLR assessment method for mackerel icefish ... model (GYM) packages, which derives population numbers-at-age and projects these numbers forward under ... the given harvest control rule to set a two-year total allowable catch (TAC). One issue is the ... growth curve to estimate an appropriate density-at-age for the population. A bootstrap procedure is ... resultant two-year TAC), will be in a length- not an age-structured paradigm. In such a length-based ... pro- posed method as a new assessment procedure for this stock, a three-year comparison between the ... proposed method and the CMIX/GYM procedure was performed for the years 2006 to 2009. For each year, the ...
Science Journal Paper : CCAMLR Science, Volume 17 (CCAMLR Science, Volume 17) : 129–137 : Auteur(s): Hillary, R.M., C.T.T. Edwards, R.E. Mitchell and D.J. Agnew
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A rationale for conservation areas within Antarctic waters
marine living resources’ (Article IX 2 (b)). In order to select meaningful boundaries for such areas ... Paper Title: A rationale for conservation areas within Antarctic waters Abstract / Description ... available, the following six potential conservation areas are proposed: 70°W- 15°W 15°W- 40°E 40°E- 90°E 90 ... °E- 150°E 150°E- 160°W 160°W- 70°W Examples are given of options available for management approaches ... regions might suffice as an initial basis for a workable management regime, under the ecosystem ... ecological basis. AN ECOLOGICAL BASIS FOR DELINEATING CONSERVATION AREAS water circulation and ... krill within major gyres has led to an examination of samples for evidence of morphological or ... from an anomaly within sector 5. As mentioned by Mackintosh, Discovery II did not cover the main ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/4 (Selected Scientific Papers, SC-CAMLR-SSP/4) : 513-535 : Auteur(s): Chittleborough, R.G.
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Improving estimates of Adélie penguin breeding population size: developing factors to adjust one-off population counts for availability bias
to adjust one-off population counts for availability bias Abstract / Description: New methods are ... presented for the collection and development of data to adjust counts of Adélie penguins made at any time in ... the breeding season to an estimate of the breeding population. The development of ‘availability ... population obtained by adjusting a one-off count using availability adjustment factors will not account for ... vegetation, for example, may not be available for counting by an observer passing overhead in an aircraft ... , and marine species diving underwater may not be available for counting by an observer in a passing ... , means that population counts cannot always be obtained at an optimal time of a breeding season for ... develop availability adjust- ment factors for population estimation, they pro- vide important background ...
Science Journal Paper : CCAMLR Science, Volume 17 (CCAMLR Science, Volume 17) : 229–241 : Auteur(s): Southwell, C., J. McKinlay, L. Emmerson, R. Trebilco and K. Newbery
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Biological parameters for icefish (Chionobathyscus dewitti) in the Ross Sea, Antarctica
mature at about 340–360 mm total length (TL) and about 3–4 years of age, and that 95% were mature at ... about 370–400 mm TL and 6–8 years of age. Counts of growth zones in sectioned otoliths were used to ... Paper Title: Biological parameters for icefish (Chionobathyscus dewitti) in the Ross Sea ... , meristics, reproductive biology, diet and age estimation. All of the icefish sampled were identified as ... were recorded for each otolith reading (Table 3). Age estimation Zone counts were converted to age ... estimates using an algorithm that sums three time compo- nents. The equation used to estimate the age of ... number of opaque zones present for fish i; w = an edge interpretation correction after Francis et al ... for all other cases. An opaque zone completion date of 1 December and a spawning date of 1 February ...
Science Journal Paper : CCAMLR Science, Volume 15 (CCAMLR Science, Volume 15) : 139–165 : Auteur(s): Sutton, C.P., M.J. Manning, D.W. Stevens and P.M. Marriott
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The biology, ecology and development of fishery management advice for the anomuran crabs at South Georgia (CCAMLR Subarea 48.3)
Paper Title: The biology, ecology and development of fishery management advice for the anomuran ... crabs at South Georgia (CCAMLR Subarea 48.3) Abstract / Description: This review summarises the ... available information on the biology and ecology of the lithodids at South Georgia and provides an overview ... of the development of a management regime for them. Finally it aims to highlight areas in which ... (Lovrich and Vinuesa, 1999) and enters the fishery at an approximate age of 15 years (Lovrich, 1997 ... and provides an over- view of the development of a management regime for them. Finally, it aims to ... 'S 55°15'S 55°30'S 55°45'S 5 Fishery management advice for the anomuran crabs at South Georgia ... ) 40 0– 1 60 0 13 5– 80 0 42 0– 2 50 0 60 0– 1 20 0 45 0– 60 5 Si ze ra ng e C ...
Science Journal Paper : CCAMLR Science, Volume 19 (CCAMLR Science, Volume 19) : 1–15 : Auteur(s): Belchier, M., T. Peatman and J. Brown
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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
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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
fishing for toothfish (Dissostichus eleginoides) around South Georgia Abstract / Description: Observer ... and 4 animals, and have a relatively lower impact on catches, depressing CPUE by up to 20%. Sperm ... 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 ... South Georgia Li ne s S P W o bs er ve d (% ) 100 90 80 70 60 50 40 30 20 10 0 May ... types were killer whales, sperm whales and both species. An overall correction factor for the year can ... cetaceans observed (Table 1) it is possible to estimate the aver- age consumption per animal. For killer ... 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