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Length-at-age in juvenile Patagonian toothfish (Dissostichus eleginoides)
density observed. Additionally, ages were predicted for each fish based on length, and compared with ages ... estimated to be from fish 1+ or 2+ years old, with mean total lengths of 32.5 cm and 41.3 cm respectively ... . No difference was found between predicted and estimated ages. We conclude that the two dominant modes ... observed in the length density represent different age cohorts separated by one year. File: 01ashford.pdf ... INTRODUCTION In recent years a fi shery for Patagonian tooth- fi sh (Dissostichus eleginoides) has developed ... using square moulds, before being ground individually. Sections were mounted on slides for reading ... to age classes, we predicted ages for each fi sh based on its length. Predicted ages were then ... qij is the proportion of fi sh of age i within an age subsample for a length j. RESULTS Of the ...
Science Journal Paper : CCAMLR Science, Volume 9 (CCAMLR Science, Volume 9) : 1–10 : Autor(es): Ashford, J., C. Jones, S. Bobko and I. Everson
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Beyond MSY: a consideration of definitions of management objectives
Article II of the CCAMLR Convention. The criteria will depend on whether the main concern is with ... / Description: The concept of ‘Maximum Sustainable Yield’ (MSY) has provided a useful guideline for resource ... assessment. Suggestions are made for the provision of advice to the Commission for the finfish and krill ... nominal effort each year, based on the values of F and fishing effort in the most recent years. Since ... remaining constant, GNAI would probably be the same as MSY, and both provide clear guidance on the need for ... CONSIDERATIONS Recruitment overfishing A fish population is usually thought of in two parts. For the first ... fishing practice, the distinction is an important one that exists for all fish except perhaps for a f~w ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/4 (Selected Scientific Papers, SC-CAMLR-SSP/4) : 299-322 : Autor(es): Gulland, J.A.
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Krill population biology during the 1991 Chilean Antarctic krill fishery
during krill fishing operations around the South Shetland Islands on board the Chilean factory vessel ... size from 1.5 to 3 cm). Two subsamples of 100 specimens each were taken from 50 samples and analysed ... . The fishing ground was divided into two areas: Area A, north of the South Shetland Islands; and Area B ... 419 hauls. In Area A, a unimodal size frequency distribution was found; the size range was between 30 ... between 30 and 55 mm TL, with a mean TL of 45 mm for females and 48 mm for males. A very weak mode for ... other (modal length 32 mm) for juvenile specimens between 20 and 39 mm TL. Females comprised 47.1 ... (ENDEPES), collected biological information on krill catches. The main objective of this article is to ... length mode of specimens between 30 and 55 mm TL, a mean TL of 45 mm for females and 48 mm for males ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/9 (Selected Scientific Papers, SC-CAMLR-SSP/9) : 223–235 : Autor(es): Mujica R., A., E. Acuña S. and A. Rivera O.
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Acoustic data analysis and models of krill spatial distribution
/ Description: Acoustic data obtained on 4-5 January 1987 aboard the R/V Professor Siedlecki were used in three ... descriptors of krill spatial aggregation: power spectra for krill biomass fluctuations in space, semivariogram ... wavenumber spectrum resembles a white noise at scales of 2-20 km, although at scales smaller than 1 km the ... over most distances between points except for the distances smaller than 1 km. The computed frequency ... and plays an important role in supporting animal populations such as whales, seals and penguins as ... swarms have a diameter smaller than 200 m and that the observed biomass is an average for a 200 m trace ... ) supports this concept. We make an attempt to model the krill biomass spectrum on the basis of the ... (cycles/km) Power spectra for krill at the 2-20 km scale observed in this analysis (line) and by Weber ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/5 – Part I (Selected Scientific Papers, SC-CAMLR-SSP/5 – Part I) : 311–329 : Autor(es): Morin, A., A. Okubo and K. Kawasaki
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Acoustic estimates of krill density at South Georgia, 1981 to 1998
% confidence limits <15 g m-2). For five of the summers between 1990 and 1998 it was possible to calculate ... separate density estimates for northeastern and northwestern South Georgia, and in four of these seasons ... from year to year over that time, ranging from ≈ 2 to ≈ 150 g m-2 (fresh mass). The 1982, 1991 and ... for an area equivalent to the western box. In three other of the years considered here data were ... given year is less than p - o for all years, then the year in Acoustic estimates of krill density ... the year in which krill density at the island was the lowest of all years for which data are ... earlier cruises for areas corresponding to those boxes. For some years, however, data were not available ...
Science Journal Paper : CCAMLR Science, Volume 6 (CCAMLR Science, Volume 6) : 47–57 : Autor(es): Brierley, A.S., J.L. Watkins, C. Goss, M.T. Wilkinson and I. Everson
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Movement, growth and available abundance to the fishery of Dissostichus eleginoides Smitt, 1898 at Heard Island, derived from tagging experiments
separate between shelves and banks separated by deep water. More particularly, the separation of stocks on ... resident during their phase in the depth range of the fishing grounds, but they move on once they approach ... end of the size range normally found on the grounds. These four long-range movers provide the first ... for the management of toothfish stocks and that trends in abundance derived from these experiments ... te d nu m be rs (m illi on s) 1998 1999 2000 2001 Year 50 40 30 20 10 0 P re di ct ... . In each simulation year, the biomass is recalculated by adding an amount for annual growth and ... the GYM, based on parameters for HIMI toothfi sh used in SC-CAMLR (2001). For a given year in the ... la bl e nu m be rs (m ill io ns ) 1998 1999 2000 2001 Year 0 10 20 30 40 50 Pr ed ic ...
Science Journal Paper : CCAMLR Science, Volume 9 (CCAMLR Science, Volume 9) : 33–48 : Autor(es): Williams, R., G.N. Tuck, A.J. Constable and T. Lamb
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Use of indices of predator status and performance in CCAMLR fishery management
specific approach is provided, involving an assessment procedure and recommendations for management action ... recommendations for restrictions on the magnitude, timing and location of harvesting are reviewed,taking account ... of likely operational constraints on fisheries. File: 20-Croxall.pdf ... Abstract / Description: This paper investigates how data on, or related to, reproductive performance of ... environment, evidence for short-term changes (year-to-year differences or trends over three to five years ... changes. The relative merits and feasibilities of recommendations for restrictions on the magnitude ... Management Strategies? I believe that there are at least two main reasons for doing this. First, in the ... will obviously include provision for restraint on harvesting under some circumstances; conversely it ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/6 (Selected Scientific Papers, SC-CAMLR-SSP/6) : 353–365 : Autor(es): Croxall, J.P.
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Low genetic diversity and temporal stability in the Antarctic toothfish (Dissostichus mawsoni) from near-continental seas of Antarctica
locations, or between samples collected in consecutive years, were observed. These results, based on ... data on the DNA analysis of recent (2011–2013) samplings of Antarctic toothfish (Dissostichus mawsoni ... allelic frequencies for several loci compared to previously published data highlight the need for further ... 54.1 cm) move to the bottom, become benthic and spend a few years on the continen- tal shelf at depths ... locations, or between samples collected in consecutive years, were observed. These results, based on ... isolated population of D. mawsoni seems very unlikely given the long (almost two years) pelagic stage ... samples for genetic analysis were fixed in 96% ethanol on board the fishery vessels. Details of the ...
Science Journal Paper : CCAMLR Science, Volume 21 (CCAMLR Science, Volume 21) : 1–9 : Autor(es): Mugue, N.S., A.F. Petrov, D.A. Zelenina, I.I. Gordeev and A.A. Sergeev
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Composition and characteristics of ichthyofauna in pelagic waters of South Georgia (Subarea 48.3)
distribution based on survey data for the years 1986 to 1990 and krill distribution based on commercial catch ... and Shag Rocks over several years. This paper, together with summaries of results of bottom ... BMRT Anchar (1990) over one to two days. Each series consisted of five to seven tows of 10 to 20 ... . The trawl was hauled on board after towing in each of these depth layers. Two to three series of ...
Science Journal Paper : CCAMLR Science, Volume 5 (CCAMLR Science, Volume 5) : 125–164 : Autor(es): Frolkina, G.A., M.P. Konstantinova and I.A Trunov
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Movement and growth of tagged Dissostichus eleginoides around South Georgia and Shag Rocks (Subarea 48.3)
experimental pot fishing in 2000 and 2001, and have been at liberty from one to two years. Four fish were ... at 42°S after about one year at liberty from some opportunistic tagging carried out on a toothfish ... strontium chloride or oxytetracycline that places a permanent chemical marker on the otolith indicating the ... tagged and recaptured from the same longline vessel in 2002 after up to two months at liberty. The fish ... released during experimental pot fi shing in 2000 and 2001, and have been at liberty from one to two years ... ‘T-bar’ tags indicating a reward for the return of the tag on recapture as well as address, fax and ... an approximate spring balance measurement that does not provide useful data for growth comparisons ... liberty for each fi sh. Von Bertalanffy growth parameters used are based on: (i) toothfi sh caught by ...
Science Journal Paper : CCAMLR Science, Volume 10 (CCAMLR Science, Volume 10) : 101–111 : Autor(es): Marlow, T.R., D.J. Agnew, M.G. Purves and I. Everson