Resultados de la búsqueda

1. Krill biomass in Area 48 and Area 58: recalculations of FIBEX data

   Green et al. (1990). The new estimates were on average 4.76 times larger than the old estimates for ... estimates of mean density and biomass for the Indian Ocean sector and the West Atlantic sector as well as ... for FAO Statistical Area 41, and CCAMLR Subareas 48.1, 48.2, 48.3, 48.6 and Division 58.4.2. Density ... workshop. Estimates for the different areas were also calculated using the target strength relationships of ... laill for an interval (set either on the basis of time or on distance steamed) of ship's track was ... . Taken together these uncertainties underline the need for more information on the TS of krill at 50 ... were on average 4.76 times larger than the old estimates for those cruises (seven out of the nine ... that all data were available in equivalent units prior to analysis, MVBS values for these two cruises ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/9 (Selected Scientific Papers, SC-CAMLR-SSP/9) : 157–181 : Autor(es): Trathan, P.N., D.J. Agnew, D.G.M. Miller, J.L. Watkins, I. Everson, M.R. Thorley, E. Murphy, A.W.A. Murray and C. Goss

2. Length-based assessments revisited – why stock status and fishing mortality of long-lived species such as toothfish cannot be inferred from length-frequency data alone

   status and fishing mortality for long-lived fish species such as Patagonian toothfish (Dissostichus ... other informative estimators for stock abundance and productivity, the review and the simulations ... highlight that interpretation of raw length-frequency data and single length-based indicators for stock ... over two or three decades (Constable et al., 2000). At the core of this approach are rules for ... fishery operations for an assessment of the sta- tus and productivity of the fished stocks to estimate ... for age determination. Based on spatially concentrated tagging effort, tag-based assessments using ... failure are the poor qual- ity and quantity of data, and the strong reliance on tag-recapture data for ...

   Science Journal Paper : CCAMLR Science, Volume 18 (CCAMLR Science, Volume 18) : 57–73 : Autor(es): Ziegler, P.E., D.C. Welsford and A.J. Constable

3. Is current management of the Antarctic krill fishery in the Atlantic sector of the Southern Ocean precautionary?

   conservatively estimated subarea biomass in up to 20% of years due to high variability in krill biomass indices ... about the state of the regional krill stock. In this region, krill fishing is permitted in an area of ... approximately 3.5 million km 2 which is divided into four subareas (labelled Subareas 48.1 to 48.4) for ... . There is some evidence for a decline in the abundance of krill in the 1980s, but no evidence of a ... for 20 years would reduce the krill stock by 2% (SC-CAMLR, 2011). Clearly, any significantly greater ... /85 until 1995/96 were on average an order of magnitude less than during previous years’ (beginning ... ). These include objectives for fished stocks and the wider ecosystem, including predators that feed on ... catch limits exceed 9.3% of conservatively estimated subarea biomass in up to 20% of years due to high ...

   Science Journal Paper : CCAMLR Science, Volume 23 (CCAMLR Science, Volume 23) : 31–51 : Autor(es): Hill, S.L., A. Atkinson, C. Darby, S. Fielding, B.A. Krafft, O.R. Godø, G. Skaret, P.N. Trathan and J.L. Watkins

4. Status of the coastal stocks of Dissostichus spp. in East Antarctica (Divisions 58.4.1 and 58.4.2)

   with the Ross Sea, where an analytical assessment has been possible for several years, and through ... . An experiment run from 2005 to 2008 required the tagging of toothfish as a prerequisite for ... 58.4.1 and 58.4.2) Abstract / Description:  Exploratory fisheries for Dissostichus spp. have been ... operating off the coast of East Antarctica (30°E–150°E; FAO/CCAMLR Divisions 58.4.1 and 58.4.2) since 2003 ... 58.4.2. Fishing years extend from 1 December of the previous year to 30 November of the named year ... for several years, and through analysis of local depletion events. Results indicated SSRU vulnerable ... also been assessed (SC-CAMLR, 2007). Information on life-history parameters is available for all ... been operating on the continental shelf and shelf slope off the coast of East Antarctica (30°E–150°E ...

   Science Journal Paper : CCAMLR Science, Volume 16 (CCAMLR Science, Volume 16) : 71–100 : Autor(es): Agnew, D.J., C. Edwards, R. Hillary, R. Mitchell and L.J. López Abellán

5. Mesopelagic fish of the Southern Ocean - summary results of recent Soviet studies

   Abstract / Description:  Since 1963, Soviet research on Antarctic mesopelagic fish has been carried out as ... a part of the general multi-disciplinary program of research on Antarctic biological resources ... . Studies concentrate primarily on the following four most abundant species: Electrona carlsbergi, Electrona ... data are available on their feeding, reproduction and age/length composition. The paper summarizes ... (Konstantinova, 1987, Atlantic sector). Growth rates during the first two years of life were found to be 30 to ... assessment should thus be attempted for each species separately. As mentioned above, spawning and feeding of ... the ACC waters which have an adequate supply of food both for young and adult fish throughout the ... of food items. E. antarctica is an opportunistic feeder and feeds on almost any abundant food ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/7 (Selected Scientific Papers, SC-CAMLR-SSP/7) : 433–457 : Autor(es): Sabourenkov, E.N.

6. Trends in relative abundance of fjord Notothenia rossii, Gobionotothen gibberifrons and Notothenia coriiceps at Potter Cove, South Shetland Islands, after commercial fishing in the area

   reported for the period 1983-1990. A trend of increasing N. rossii catches was observed, but the levels of ... inshore sub-populations of N. rossii and G. gibberifrons over the last 16 years was most probably caused ... with historical information on offshore commercial fishing and with the results of scientific surveys ... abundance were analysed using an ANOVA design, grouping the hauls on a sp1it;year basis. The split-year is ... performed on total and relative catches taken at PC are shown in Table 1. Split-year (1 May to 30 April ... per haul was highly variable between years and within the same season. Therefore, for analysis, fish ... . coriiceps. We have used N . coriiceps as a reference species to obtain an abundance index for N. rossii ...

   Science Journal Paper : CCAMLR Science, Volume 7 (CCAMLR Science, Volume 7) : 43–52 : Autor(es): Barrera-Oro, E.R., E.R. Marschoff and R.J. Casaux

7. Management and uncertainty: the example of South Georgia

   :  Decisions on fishery management are often made with some degree of uncertainty in scientific advice. Such ... . From an examination of Articles IX 2(f) and XV 2(e, d) of the CCAMLR Convention it follows that a ... (including the effects of doing nothing) could provide a procedure for providing advice that could cope with ... closure become apparent. On the central view, it would take only a year after a 10-year closure for ... could say with absolute certainty that a complete closure for x years would rebuild the stocks to a ... . Article IX 2 (f) states that the Commission shall "formulate, adopt and revise conservation measures on ... present M=O.ll, F=0.65. Annual recruitment, as numbers at 3 years old, has fallen from some 20 ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/3 (Selected Scientific Papers, SC-CAMLR-SSP/3) : 341-353 : Autor(es): Gulland, J.A.

8. Fatty acid and stable isotope analyses to infer diet of Antarctic toothfish caught in the southern Ross Sea

   in the southern Ross Sea Abstract / Description:  To infer important prey resources for Antarctic ... evidence that a combination of these two techniques can delineate the main prey items of Antarctic ... sample collection and biomarker analyses for more pelagic and benthic biota are needed to better ... isotope ratio has been used extensively to delineate the trophic position of an animal (DeNiro and ... for freeze-dried organic mat- ter sources and animal tissues with a solution of methanol and ... mixture was shaken, closed under nitrogen, and then heated on a hot block at 100°C for 5 min. After ... programmed at 180°C for 5 min, raised from 180°C to 230°C at 3°C min–1, and then finally maintained at 230 ...

   Science Journal Paper : CCAMLR Science, Volume 20 (CCAMLR Science, Volume 20) : 21–36 : Autor(es): Jo, H.-S., I. Yeon, C. Lim, S.M. Hanchet, D.-W. Lee and C.-K. Kang

9. A hybrid approach to acoustic classification and length estimation of krill

   / Description:  The problem of acoustically identifying and estimating the sizes of two euphausiid species is ... components are the mean ratios of the volume backscattering coefficients, measured at two different ... frequencies. The decisions on the species and the relative misclassification errors are calculated ... individually for each component of a vector, using classical Bayesian techniques. Classification probabilities ... decisions on the species and the relative misclassifi cation errors are calculated individually for each ... cult. To measure target strength in situ, an acoustic resolution volume must be based on a single ... animal measurement. For small school- ing organisms, such as euphausiids, this criterion is seldom met ... error |δ| is high for afj / fi < a1, decreases approaching the middle point between the two bends ...

   Science Journal Paper : CCAMLR Science, Volume 11 (CCAMLR Science, Volume 11) : 33–58 : Autor(es): Azzali, M., I. Leonori and G. Lanciani

10. Measurements of differences in the target strength of Antarctic krill (Euphausia superba) swarms at 38 kHz and 120 kHz

    differences in the mean back-scattering strength of swarms simultaneously insonified at these two frequencies ... in average target strength at these two frequencies. The results are in good agreement with recent ... experimental work on the target strength of encaged E. superba at 38 and 120 kHz but are in major conflict with ... Receiving Sensitivity (SL + VRS) for both sounders was measured to within an estimated ± 0.5 dB by ... over the past three years. Spot checks on SL and VRS made before, during and after the cruise with a ... 100 m over an interval in which no krill were evident on either sounder in the upper 100 m, to check ... were interchanged, removing any fear that the differences were an artefact of differences in the two ...

    Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/7 (Selected Scientific Papers, SC-CAMLR-SSP/7) : 75–86 : Autor(es): Hampton, I.

Páginas