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.
 

В настоящем документе предлагается репрезентативная система морских охраняемых районов (РСМОР) в Восточно-Антарктической области планирования, определенной на Семинаре АНТКОМ по морским охраняемым районам (МОР) в 2011 г. (WS-MPA-11). В нем также предлагается, чтобы Восточно-Антарктическая РСМОР была одобрена НК-АНТКОМ и чтобы она была рекомендована Комиссии в рамках обязательства по выделению МОР к 2012 г. Это предложение уточняет версию 2010 г. Оно включает результаты проходившего во Франции в мае 2011 г. семинара по МОР и учитывает дискуссии на WS-MPA-11. Данный отчет разделен на три части: (1) описание РСМОР, (2) анализ природоохранных ценностей и компромиссов для МОР в Восточно-Антарктической области планирования и (3) вспомогательные материалы, содержащие дополнительную информацию, подкрепляющую анализ и метод в целом. В случае успеха предложения районы, указанные в РСМОР, будут определены отдельными мерами по сохранению в рамках общей меры по МОР, как предлагается в документе 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.

The Patagonian toothfish fishery in the EEZ of Kerguelen (division 58-5-1) and Crozet (subarea 58-6) is under the management of the competent French authority, the French Southern and Antarctic Territories (TAAF). The TAAF relies on advice from several scientific institutions, in particular from the National Museum of Natural History, Paris (MNHN).
Within the context of this advice, the MNHN made recommendations in order to minimize fish by-catch of fish that are not targeted by the fishery campaign of 2011-2012. The technical recommendations set by the authority were updated by taking this advice into account.
The present document aims at informing the participants about the content of these technical recommendations. Those recommendations will be assessed all along the 2011-2012 campaign and, after the results obtained with the enforcement of these measures are analyzed, some quantified targets will be defined in order to reduce the fish by-catch during the next campaign.
The allotment of quotas to the fishing vessels targeting the Patagonian toothfish in the Kerguelen EEZ (division 58-5-1) and Crozet (subarea 58-6) are based on objective criteria for assessing the vessels’ performance. These criteria comprise all together socio-economic aspects and fishery history, steps implemented by each vessel to minimize avian mortality, initiatives for preserving the environment and the capacity to fish its own quota. The results regarding the accidental mortality represent one of the main factors for assessing fishing vessels. In the future, if by-catch mitigation methods demonstrate their efficiency, the fishing vessels will also be assessed according to their ability to achieve the targets in reducing the by-catch of non targeted fish species.
The French Austral and Antarctic Territories added to the technical measures for the Patagonian toothfish fisheries in the EEZ of Kerguelen and Crozet (division 58-5-1 and subarea 58-6) some general measures (paragraph 1 above) and some specific measures (paragraph 2 above). The relevant portions of these technical recommendations are given below.
At the end of the 2011-2012 fishery campaign, the results’ analysis will allow the settings of quantified targets in terms of reducing the fish by-catch in the EEZ of Kerguelen (division 58-5-1) and Crozet (subarea 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.