CCAMLR

Monitoring and hydroacoustic assessment of the distribution and biomass of krill (Euphausia superba) was held on board the BIC Humboldt during scientific campaigns Peru to Antarctica in the austral summer: Antar XXI (15 to 22 February 2013) and Antar XXII (22 to 31 January 2014). The areas included Bransfield Strait, Joinville and around Elephant Island (Antar XXI: : 8 040 nm2 with 10 transects; ANTAR XXII: 21 070.62 nm2 with 17 transects) .The SIMRAD EK60 scientific echosounder used for multifrequency 120 and 38 kHz, respectively. This system is calibrated according to the procedure of ICES. For pelagic trawl hauls- Pelagic Engel gear were used for checking acoustic signals (Antar XXI: 9 stations; ANTAR XXII: 16 stations). Results indicated that krill swarms during the day swarms were recorded at high densities between 20 and 50 m deep while overnight, dispersed and scattered swarms were detected from the surface to 20 m deep. A wide distribution of krill in the study area, the highest densities (> 1000 m / mn²) were observed around Elephant Island and Joinville was recorded; while the lowest were recorded in the Bransfield Strait and between Deception Island and Isla Torre (250-1 000 m / mn²). The estimations of hydroacoustic biomass krill by the method of Distorted Stochastic Approximation Wave (SDWBA) were 876.367 t and t 7'330,574 during ANTAR XXI and XXII respectively. The estimated biomass in Elephant Island (4'569,039 t) represents 62.3% of all existing biomass in the study area.

Six Members notified a total of 18 vessels for krill fisheries in 2016/17 in Subareas 48.1 (17 vessels), 48.2 (16), 48.3 (15) and 48.4 (10), and Divisions 58.4.1 (3) and 58.4.2 (3); there were no notifications submitted for exploratory fisheries for krill. Notification details are available on the CCAMLR website and the notified information on the fishing operation and gear is summarised in this paper. Participating Members are thanked for providing feedback and assistance in developing the new online notification system.

Analysis of the data from tooth fish fishery in the northern part of the Ross Sea (SSRU 88.1 B, C and G) revealed that the current approach to analyze longline fishery data in the presence of questionable CPUE values does not allow obtaining adequate information for decision-making.  Necessity to develop procedures for analyzing logline fishery data with aims to provide information for scientifically based decision-making in relation to questionable CPUE values have been discussed.

Following the Spanish research plan approved by the SC-CCAMLR XXXII, during the third year of the multi-year research survey in the Division 58.4.1, as far as the ice condition allowed, the F/V Tronio has returned to the same places surveyed in the previous seasons and a prospection all along the area has been carried on.

Preliminary results of the last 2015/16 season survey are presented together with a comparative analysis of the three-seasons carried out in this division. A depletion experiment has been made in each of the prospected SSRUs. Results in SSRUs 5841H and G are not conclusive. Likewise tag-recapture results have been poorer than expected. Accessibility problems by the ice cover and traces of IUU fishing found in the proposed areas might have great influence in the results.

The IEO continues reading of otoliths for ageing Antarctic toothfish. These data will be added to the input data in the near future in order to carry out an integrated assessment of Dissostichus mawsoni stocks in this Division.   

Results of other data collected such as fish bycatch or incidental catch of benthic taxa are also presented.

The condition and survival of Antarctic krill (Euphausia superba) strongly depends on sea ice during winter. How krill utilize sea ice depends on several factors such as region and developmental stage. A comprehensive understanding of sea ice habitat use by krill, however, remains largely unknown. The aim of this study was to improve the understanding of the krill's interaction with the sea ice habitat during winter/early spring by conducting large-scale sampling of the ice-water interface (0-2 m) and comparing the size and developmental stage composition of krill with the pelagic population (0-500 m). Results show that the population in the Northern Weddell Sea consisted mainly of krill that were <1 year old (age class 0; AC0), and that it was comprised of multiple cohorts. Size per developmental stage differed spatially, indicating that the krill were likely advected from various origins. The size distribution of krill differed between the two depth strata sampled. Larval stages with a relatively small size (mean 7-8 mm) dominated the upper two meter layer of the water column, while larger larvae and ACO juveniles (mean 14-15) were proportionally more abundant in the o-500 m stratum. Our results show that, as krill mature, their vertical distribution and utilization of the sea ice appear to change gradually. This could be the result of changes in physiology and/or behaviour, as, e.g., the krill's energy demand and swimming capacity increase with size and age. The degree of sea ice association will have an effect on large-scale distribution patterns of AC0 krill and on predictions of the consequences of sea ice decline on their survival over winter.

In recent years there have been a number of changes in the criteria, metrics and application of methods used in setting research catch limits in research blocks as well as assessing progress in research plans. This has resulted in some confusion in the application of methods and the intended purpose of the metrics included in the summary table presented to the Scientific Committee that includes recommended research catch limits. Given the importance of this table, and the need to ensure clarity in the methods used to generate and update the data included therein, the Secretariat was requested to update the summary table using the most recent data available and to detail the methods used for local biomass estimation (SC-CAMLR-XXXIV, paragraph 3.232 (i)). This paper provides an updated summary table, with a full description of the methods used in that updated table, as well as some history of decisions made by WG-FSA in developing the overall approach. Challenges encountered when updating the metrics in the summary table are detailed along with points that might require further clarity and consideration by WG-SAM and WG-FSA.