CCAMLR

A length-based projection model is used to estimate catch limits for the 2011/12 fishing season for Champsocephalus gunnari in CCAMLR sub area 48.3. The model is initialised using estimated numbers at length derived from survey length density and biomass density data, removing the need for cohort identification associated with age based projection models used historically. Application of the harvest control rule ensuring 75% escapement after a two year projection period yielded a total allowable catch of 3,072 tonnes for 2011/12 and 2,933 tonnes for 2012/13.

The 2011 groundfish survey took place at South Georgia and Shag Rocks on the FV Sil between the 27th January and 6th February 2011. 87 random hauls were completed, with good coverage across the shelf. Catch-weighted length frequencies of mackerel icefish indicated that 3+ sized fish dominated at Shag Rocks, however 1+ and 2+ sized fish were present in larger proportions at South Georgia. A mean biomass of 49,353 tonnes was estimated for mackerel icefish, with a lower 1-sided 95% CL of 31,373 tonnes. Euphausiidae was the dominant prey item in the mackerel icefish diet with increased dietary importance compared to 2009/2010. As seen during the 2009 and 2010 survey, icefish remained close to the bottom and very few acoustic marks were observed in the water column. Themisto sp. was the only other prey that made a substantial contribution to the diet, occurring in 39.47% of stomachs.
Catches of Patagonian toothfish were greater than in 2009 and 2010, with a large haul of 40-45cm fish (1.6t) around Shag Rocks. These fish are likely to be the same cohort that was evident at Shag Rocks in 2010 (fish were then 29-39cm age 2+).

A stock assessment of the Patagonian toothfish (Dissostichus eleginoides) at Kerguelen Island (division 58.5.1 of the CCAMLR) was undertaken with the modeling software CASAL, using different statistical and biological datasets: abundance estimation from the POKER 1 and 2 scientific cruises, catch per unit effort of the commercial fishery, tagging survey, sample size frequencies… CASAL is a simple population-modeling tool, applied to a single area and based on sex combination. The spatial complexity of the fishery is modeled using different functions for fishery selectivity depending on the fishing zone and the type of fishing vessels (trawlers, long-liners). The fishing zone for the long-liners is divided in four areas (North, East, South, Skiff Bank) and in two depth categories: less than and more than 1,500m. Commercial catches are integrated in the model by CCAMLR season. A weighted combination of datasets was integrated using the effective samples’ size calculated at the level of each haul. An iteratively estimated process error was applied to the length frequency data. With an initial biomass of about 200,000 tons, the modeling tends to present results which are consistent with the stock assessments undertaken by the Australian scientific team at Heard (subarea 58-5-2) and over the Kerguelen Plateau. The biomass long-term projection, done for the Patagonian toothfish with a simulated 5,100 tons catch by long-liners, fulfils the CCAMLR management rules. However, these results should be considered with caution and research studies aiming at collecting more biological data and getting a better understanding of the population spatial complexity should be continued.

Results of comparative histological analysis of gonads of female and male Antarctic toothfish Dissostichus mawsoni caught by Russian longliners in the Ross Ross Sea of the Pacific sector in 2004/2005 - 2006/2007 seasons are presented. Morphological indices of females and males, age, indices of gonads, fecundity, and condition by Fulton are described. The criteria of assessment of maturity stages of ovaries, cytological indices of oocytes, and the type of toothfish oogenesis are determined. It was established that in the period of fishing, females and males with gonads at maturity stage III were dominated. Ovaries contain two groups of oocytes of the period of trophoplasmatic growth and large oocytes of the nearest spawning season that comprise the smallest proportion of total sex cells. The individual absolute fecundity was 0.33 million eggs, relative fecundity –29 eggs per g. It is suggested that in the Ross Sea the termination of gonad maturity of toothfish takes place from March to April, and spawning takes place from June to August. By the histological data 7-40% females had prespawning ovaries condition, and diameter of their large oocytes was 1075 - 2331•10-6m in different years.

This paper summarises recent, fishery-related scientific research notified in accordance with Conservation Measure 24-01. Four notifications were received by the Secretariat for research in 2010/11, and five notifications have been received to date for research in 2011/12.

This paper summarises the data collection requirements for the exploratory fisheries for Dissostichus spp. and the general characteristics of the research hauls which may assist WG-FSA to determine the extent to which the available data may be used in developing assessments for these fisheries.

This paper summarises the data collection requirements for the exploratory fisheries for Dissostichus spp. and the general characteristics of the research hauls which may assist WG-FSA to determine the extent to which the available data may be used in developing assessments for these fisheries.

The integrated assessment of Patagonian toothfish, Dissostichus eleginoides, for the Heard and McDonald Islands (Division 58.5.2) was updated from WG-FSA-09/20. The main change other than updating total removals by sub-fishery and updating catch-at-age and catch-at-length proportions was the inclusion of random stratified trawl survey (RSTS) abundance-at-age for 2010 and 2011 and conversion of 2008 and 2009 RSTS abundance-at-length to abundance-at-age. This was possible due to the large number of otoliths collected and aged for each annual RSTS since 2008. Catch-at-length proportions for the commercial fisheries, both trawl and longline, were used for 2009 to 2011 since there were few fished aged for these years. A series of standardised longline CPUE data from one of the longline grounds (or subfishery) which has been consistently fished since 2003 was added for the first time. All three of the standardised CPUE series have minimal influence on the model parameter estimates due to the large degree of uncertainty about annual estimates but given this caveat they are useful in tracking observed and CASAL-estimated trends in catch rates.
A change of substantial consequence from the 2009 integrated assessment was the use of a value for natural mortality (M) of 0.155 whereas a value of 0.13 was used previously. Neither of these values of M was estimated in CASAL but the value of 0.155 was estimated externally to CASAL from catch-at-age and aged mark-recapture data as described in Candy et al. (2011). The consequence of using a higher M in the integrated assessment was a reduction in the estimate of B0 with a compensatory increase in R0. Using the same data as the 2009 assessment the reduction in B0 was 33.1% and the increase in R0 was 23.5%. For the updated assessment with M set to 0.155 the corresponding percentage change relative to the 2009 assessment were 25.8% and 36.9%, respectively. Since the trawl fishery, and to a lesser degree, the longline fishery catch relatively few fish that are at an age to begin spawning or older (i.e. mostly above age 14), the higher recruitment despite the higher M meant that a similar but slightly higher long-term yield was estimated for the updated assessment to that in 2009.
For the updated assessment, the long-term yield that satisfies the CCAMLR decision rules is 2 730 t.
 

In 2011 data on beach surveys, debris associated with seabird colonies, marine mammal entanglements and hydrocarbon soilings were received from South Africa, the United Kingdom, and Uruguay.  Non-fishing items such as packaging and wood remain the most common type of debris items found in beach surveys.  The fishing items found were mostly from longline origin. Plastic packaging bands continue to be found in beach surveys with closed bands found at Bird Island (1) and King George Island (3), despite Conservation Measure 26-01 requiring packaging bands to be cut up into 30 cm pieces.
The amount of debris in colonies of grey-headed albatrosses and black-browed albatrosses at Bird Island has increased recently, and the major category of items found was plastics.  The amount of fishing related items (fishing lines and hooks) found in wandering albatross colonies remains the foremost debris item found in each season.
The number of marine mammal entanglements increased in 2011 with packaging bands and fishing gear the main entangling materials.
There was only one new hydrocarbon soiling reported from King Edward Point in 2010.  
The reported hook loss from the longline catch and effort data shows that while it is a small percentage of the total hook set, it is a considerable amount of gear that is lost in the water.