CCAMLR

The potential for data poor exploratory fisheries in the CAMLR Convention area to provide sufficient data to lead to formal stock assessments of Dissostichus spp. is evaluated and recommendations are made for optimizing this potential.  The types of data that have led to successful assessments in the past are reviewed. Exploratory fisheries and research questions for subareas without currently assessed stocks (48.6, 58.4, parts of 88.1 and 88.2) are summarized. The multi-nation, multi-year exploratory fishery in the Ross Sea leading to an assessment of D. mawsoni and the fishery for D. eleginoides in the northern South Sandwich Islands are used as examples of what can be achieved using exploratory fisheries to provide information for stock assessment. Three sources of data potentially collectable from exploratory fisheries have proved successful in the past: 1) tag mark and recapture; 2) collection and reading of otoliths; and 3) recording of length, sex and gonad stage. It is suggested that research standards for data collected by vessels in exploratory fisheries be focused on providing these three types of data and that detailed descriptions of CPUE data be de-emphasized. Focusing effort on subareas/divisions in which tagged fish have already been released is recommended to maximize recapture potential for existing tags while increasing the numbers of newly tagged fish.  The subareas/divisions should be prioritized according to the amount of information currently available, and the prospect of acquiring a sufficient amount of data with which to conduct a formal assessment.

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.
 

This paper proposes a representative system of marine protected areas (RSMPA) in the East Antarctica Planning Domain identified by the CCAMLR Worksop on Marine Protected Areas (MPAs) in 2011 (WS‐MPA‐11). It also proposes that the East Antarctica RSMPA be endorsed by the SC‐CAMLR and that it be recommended to the Commission as part of the commitment to delivering MPAs by 2012. This proposal is an updated version from 2010. It includes results from the workshop in France on MPAs in May 2011 and takes into account discussions at WS‐MPA‐11. This report is divided into three sections: (1) description of the RSMPA, (2) analysis of conservation values and trade‐offs for MPAs in the East Antarctica Planning Domain and (3) supporting materials providing further information underpinning the analyses and approach in general. If successful, the areas nominated in the RSMPA would be designated by individual conservation measures under the general Measure on MPAs as proposed in 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).