WG-SAM-08

Exploratory fisheries for Dissostichus spp. have been operating in these regions for a number of consecutive years with the tagging of toothfish a prerequisite for the legal fishery. This paper presents a detailed study of the catch and effort trends in Divisions 58.4.1 and 58.4.2 and a examines 4 assessment methods based on comparative CPUE trends, local depletions, a constant recruitment Read More
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This paper details a potential methodology for performing initial stock assessments for exploratory fisheries and by-catch species, where catch data and mark-recapture data are present but more detailed data, specifically age or length structured data on catches or surveys, is either missing or poorly sampled. As an example case we use the catch data, legal and IUU, and the mark-recapture data Read More
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This paper outlines a method of calculating suitable tagging rates and total allowable catches (TACs) that would be expected to yield a pre-specified precision in a resultant abundance estimate. With respect to the tagging-based abundance estimator, we use the Lincoln-Petersen method and derive a formula that gives the expected coefficient of variation of the abundance estimate in terms of the Read More
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1. A dataset of all possible combinations of release nation, recapture nation, release year and recapture year for tags released and recaptured in the same SSRUs on the slope of 88.1 was compiled for the years 2003-2006. Recapture rate was expressed as tags captured/tags released/fish scanned (caught), all in numbers. 2. The overall size of the dataset was 734 combinations of release year, Read More
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Last two years two different approaches were used for stock assessment of Antarctic toothfish in the Ross Sea. One of them, the CASAL model, (Dunn & Hanchet, 2007; Bull et al., 2007) is mostly based on likelihoods and potentially could insure proper mutual weighting of signals from all available sources of information incorporated into the model. The second one, the TISVPA model (Vasilyev Read More
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Reconstruction of size and weight composition of Antarctic toothfish (Dissostichus mawsoni) from the data on processed commercial catches of longliners using conversion factor

A new South Georgia bathymetric dataset (SGDB) was compiled from a variety of primary sources including multi-beam swath bathymetry. Seafloor area (km2 <500m depth) within CCAMLR subarea 48.3 was calculated using this new dataset. Total seafloor area within the region closely matched existing estimates derived from nautical charts (and single point sounding data). However, the reliability Read More
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Four Operating Models (OMs) reflecting an “Optimistic”, “Intermediate”, “Less Pessimistic” and a “Pessimistic” current status for the toothfish resource in the Prince Edward Islands region are developed which take account of the different selectivities of past longline and pot fisheries. These models are used for trials of a candidate Management Procedure (MP) which could provide future TAC Read More
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nnovative multivariate statistical modelling techniques make it possible to generate spatially comprehensive species distribution layers from discontinuous biological data, by fitting complex and scale-dependent relationship between species abundance and available environmental data. The resulting species-specific distribution layers have many potential applications. We apply one such method, Read More
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Measures are developed which aim to summarise the quality of fishing event, catch, and biological sampling data from a fishing trip. In particular these measures aim to quantify the prevalence of position or time reporting errors, the diversity of catch, the extent to which catch data follow Benford's Law for the distribution of the first significant digit, whether length-frequency data have Read More
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We present a generalised spatially explicit Bayesian statistical catch-at-age population dynamics model (SPM) for developing and investigating plausible spatial movement models, and apply a preliminary development version of this model to Antarctic toothfish in the Ross Sea as an age and maturity state spatial movement model. SPM is an aggregate movement model suitable for use with large Read More
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This paper details how FOOSA, an operating foodweb model for evaluating spatially-structured harvest strategies for krill, has been implemented within the EPOC modelling framework. It also shows how the parameters developed for use in FOOSA can be adapted for use in EPOC. The paper has three main parts – an outline of the structure of EPOC, consideration of the general FOOSA structure that Read More
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In this paper, we develop an ecosystem-based, precautionary management procedure for krill fisheries which draws together past experience in CCAMLR. It provides an empirical ecosystem assessment model, a decision rule for determining local scale catch limits based on a harvest strategy and a single-species assessment of yield, and a method for implementing the procedure. The decision rule for Read More
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An updated version of the Spatial Multi-species Operating Model (SMOM) of krill-predator-fishery dynamics is described. This has been developed in response to requests for scientific advice regarding the subdivision of the precautionary catch limit for krill among 15 small-scale management units (SSMUs) in the Scotia Sea, to reduce the potential impact of fishing on land-based predators. The Read More
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Quantitative method for describing krill mass congestions based on perennial observations using trawling and hydroacoustic data is proposed. Reliable evaluation of krill resources is provided with probability methods and spatial analyses requiring knowledge of statistical distribution rules applicable for natural habitat and equal probability concentrations. Spatial analyses of krill Read More
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Admin Admin (CCAMLR Secretariat)

Publication:
(Ukrainian Antarctic Journal, 2 (2004): 170–178.)

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ic life is developed in accordance with the rules of metrology, mathematical statistics and using the biocenological regularities of water objects. The basis of evaluating the stocks of water life was investigated through biocenotic conditionality in the areas of their equal probability in concentrations. The traditional method of squares in evaluating the stocks of water life was modernized Read More
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Admin Admin (CCAMLR Secretariat)

Publication:
(Reports of the National Academy of Science of Ukraine, 12 (2006): 150–157)

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SeaBird is a generalised age- and/or stage-structured seabird population dynamics model that allows a great deal of flexibility in specifying the population dynamics, parameter estimation, and model outputs. The manual provides information on how to use SeaBird, including how to run it, how to set up the input files, descriptions of the population dynamics and estimation methods, and how to Read More
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Admin Admin (CCAMLR Secretariat)

Publication:
(Final Fisheries Report to the New Zealand Ministry of Fisheries)

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