CCAMLR

This paper presents the updates to the CCAMLR tagging database in relation to tag recapture links, and the problems associated with linking tags.
 

A generic spatially-explicit age-structured model framework is in development that will enable to evaluate data collection protocols, assessment methods and management strategies. The model framework is programmed in R to promote transparency and interactions between researchers. It is based on the FLR framework and will incorporate links to external assessments programs such as CASAL. The model framework will have a number of modules representing the fish population dynamics, harvest by fishing fleets with different gear types or metiers, sampling of data, stock assessment, and implementation of fishery management decisions.
 

At its 2010 meeting, the Scientific Committee agreed that a time series of recruitments from a well- designed survey in the Ross Sea could be a useful input into the stock assessment model and requested members develop a pre-recruit survey design. A preliminary proposal for a pre-recruit survey was presented to the 2011 meeting of WG-SAM. In this paper we provide an update of the preliminary proposal by taking into account the comments of WG-SAM. It provides the scientific rationale and background for the research proposal for a longline survey of pre-recruit toothfish in the southern Ross Sea, which has been submitted as a paper to the Scientific Committee.

We consider here the objectives of the survey, the target fish age and length classes to be monitored, appropriate survey strata size and location, the number of sets in each stratum required to achieve target c.v.s, and associated sampling methodologies. As a result of this review, we propose that the first survey be a pilot, with two main objectives:
 
(i)    To establish the feasibility of developing a time series of longline surveys to monitor pre-recruit (<100 cm TL) toothfish in the south of SSRUs 881.J and 881.L in the southern Ross Sea using standardised gear in a standardised manner; and
(ii)    To carry out experimental depth-stratified fishing in 400–600 m depth adjacent to the survey boundaries to establish the most appropriate depth strata for future annual surveys.
 

Le présent document propose un système représentatif d'aires marines protégées (RSMPA) dans le domaine de planification de l'Antarctique de l'Est identifié par l'atelier de la CCAMLR sur les aires marines protégées (AMP) en 2011 (WS-MPA-11).  Il propose, de plus, de faire approuver le RSMPA de l'Antarctique de l'Est par le SC-CAMLR qui le recommanderait à la Commission dans le cadre de son engagement à créer des AMP d'ici à 2012.  Cette proposition est une nouvelle version de celle de 2010.  Elle comporte les résultats de l'atelier qui s'est déroulé en France sur les AMP en mai 2011 et tient compte des discussions menées par le WS-MPA-11.  Ce rapport est divisé en trois sections : 1) la description du RSMPA, 2) l'analyse des valeurs à conserver et des compromis pour les AMP dans le domaine de planification de l'Antarctique de l'Est et 3) la documentation fournissant le complément d'informations à la base des analyses et de l'approche générale.  Si cette proposition est acceptée, les zones qu'il est prévu d'inclure dans le RSMPA seront désignées par des mesures de conservation individuelles dans le cadre de la mesure générale sur les AMP proposée dans CCAMLR-XXX/30.

The model of tag shedding implicit in CASAL is that of Kirkwood and Walker (KW) (1984) which models the annual tag shedding (i.e. loss) rate as a constant for individual tags. The CASAL software applies this model correctly for fish released with a single tag but does not have the facility at present to correctly apply the KW model for fish released with two tags. The solution of Dunn et al. (2005) and Hillary et al. (2006) to apply the square of the individual tag loss annual rate in CASAL over-estimates the correct proportion of fish that have retained at least one tag, and are therefore detectable, as a function of time at liberty. This over-estimation is shown to be significant and the implications for stock assessments of this are discussed.
Models of tag shedding were calibrated using data for a large sample of recaptures of fish released in the Heard and MacDonald Island (HIMI) (Division 58.5.2) Patagonian toothfish fishery that were double (Tbar) tagged fish. These models included the single-parameter KW model and 2 and 3 parameter extensions of this model. A Generalized Additive Model (GAM) was also fitted and is the most flexible in shape. The estimation method accounts for the fact that fish that have shed both tags cannot be detected and therefore do not contribute to the data but in the theory need to be considered. The KW model gave a considerably poorer fit than the other models. It is recommended that CASAL be modified to correctly handle double-tagged releases and at the same
time allow more flexible models of probability of shedding of individual tags. In lieu of this an  improved approximation compared to squaring the rate parameter is given. This approximation could be combined with a sensitivity analysis that varies the KW constant rate parameter in CASAL assessments.

According to the application that has been applied by Russian Federation in 2010 for season 2010/2011 research fishing in subarea 88.3 has been done. The work has been done by longliner “Sparta”, with two scientific observers aboard. They deployed 20 sets (trotline) at different depths. Total amount of set hooks is 87096. Research catching was carried out in SSRU B, C, and D. In SSRU A sets had not took place because of complicated ice conditions. The catch was totally analyzed for its biological characteristics. Additional catch’s biological characteristics have been analyzed too (excluding fish food analysis). According to the catch’s length variation, 30 fishes of different length have been tagged. Total catch is 256 toothfishes – 5230 kilograms weight. Data about spatial and bathymetrical distribution and nutrition of toothfish in subarea 88.3.B-D were collected 240 otolithes for age identification, 53 genetic specimens and 42 histological specimens have been collected.

La pêcherie à la légine dans les ZEE de Kerguelen (division 58-5-1) et Crozet (division 58-6) est gérée par l’administration française compétente, les Terres australes et antarctiques françaises (TAAF). Cette dernière s’appuie sur les avis émanant de plusieurs institutions scientifiques, notamment du Muséum National d’Histoire Naturel (MNHN).
Dans le cadre de cet avis, le MNHN a notamment fait connaître ses préconisations pour limiter les prises accessoires de poissons non ciblés pour la campagne de pêche 2011-2012. Les prescriptions techniques fixées par l’administration ont été actualisées en prenant en compte cet avis.
Le présent document a pour objet d’informer les participants du contenu de ces prescriptions techniques. Ces dernières seront évaluées tout au long de la campagne 2011-2012 et, après étude des résultats obtenus en application de ces mesures, des objectifs chiffrés seront fixés pour réduire les captures accessoires de poissons lors de la campagne suivante.
Les attributions de quotas aux navires pêchant la légine dans les ZEE de Kerguelen (division 58-5-1) et de Crozet (division 58-6) sont fondées sur des critères objectifs d’évaluation de la performance des navires. Ces critères comprennent à la fois les aspects socio-économiques et l’antériorité de pêche, les efforts mis en œuvre par chaque navire pour réduire la mortalité aviaire, les initiatives en vue de préserver l’environnement et la capacité à pêcher son quota. Les résultats en matière de mortalité accidentelle représentent un des principaux facteurs d’évaluation des bateaux. A l’avenir, si les méthodes d’atténuation des captures accessoires démontrent leur efficacité, les navires seront également évalués en fonction de leur capacité à remplir des objectifs en matière de réduction des captures accessoires de poissons non ciblés.
Les Terres australes et antarctiques françaises ont introduit dans les prescriptions techniques encadrant la pêche à la légine dans les ZEE de Kerguelen et de Crozet (divisions 58-5-1 et 58-6) des mesures générales (paragraphe 1 ci-après) et des mesures spécifiques (paragraphe 2 ci-après). Les extraits pertinents de ces prescriptions techniques sont reproduits ci-dessous.
A l’issue de la campagne de pêche 2011-2012, l’analyse des résultats permettra de fixer des objectifs chiffrés en matière de diminution des captures accessoires de poissons dans les ZEE de Kerguelen (division 58-5-1) et Crozet (division 58-6).

As with the 2009 assessment of Subarea 48.3, there is still uncertainty as to why there were high numbers of the 2001 cohort in commercial catches in 2009 onwards.  It is likely that it is due to a combination of a strong 2001 cohort and a change in selectivity for the commercial fleet, but it has not been possible to determine the relative importance of each explanation.
Median log-normal recruitment suggests a long-term yield of 3 200 t.  If year class strengths have been low since 1994 and continue for the next 35 years then appropriate long -term yields could be as low as 975 tonnes.  This scenario is highly unlikely as survey data from 2010 and 2011 suggest a strong 2007 cohort, and survey data from 2004 to 2008 suggest a strong 2001 cohort.
Model projections, evidence of cohort strength from the surveys and the stabilisation of both SSB and CPUE that a long-term yield in the region of 2 000 tonnes would be appropriate, at least until catch-at-age data can confirm the strength of the 2007 cohort.