Antarctic krill (Euphausia superba) is an abundant fishery resource, the harvest levels of which are expected to increase. However, many of the length classes of krill can escape through commonly used commercial trawl mesh sizes. A vital component of the overall management of a fishery is to estimate the total fishing mortality and quantify the mortality rate of individuals that escape from fishing gear. The methods for determining fishing mortality in krill are still poorly developed. We used a covered codend sampling technique followed by onboard observations made in holding tanks to monitor mortality rates of escaped krill. Haul duration, hydrological conditions, maximum fishing depth and catch composition all had no significant effect on mortality of krill escaping 16 mm mesh size nets, nor was any further mortality associated with the holding tank conditions. A non- parametric Kaplan-Meier analysis was used to model the relationship between mortality rates of escapees and time. There was a weak tendency, though not significant, for smaller individuals to suffer higher mortality than larger individuals. The mortality of krill escaping the trawl nets in our study was 4.4 ± 4.4 %, suggesting that krill are fairly tolerant of the capture-and-escape process in trawls.

This report presents the outcome from the sixth of the annual survey seasons (2016) off the South Orkney Islands including the preliminary results from continuously recorded acoustic data, krill demography and other macro zooplankton from trawl station work, krill predator sightings data as well as krill-experimental work carried out on onboard.

No reliable measures of age currently exist in the Antarctic krill, Euphausia superba (Dana, 1852). The eyestalks from 51 individuals were dissected, cut in longitudinal sections and studied for identifying growth zones. The krill was collected at the South Orkney Islands during January and February 2015, and varied between 30 and 53 mm in total body length. Up to six growth zones were identified, each zone consisting of one light and one dark section. The width of the longitudinal sections increased with increasing body length, although there were differences between sexes. Females tended to have narrower growth zones from the third zone and onwards compared with males. Data show that male subadult stages (MIIA1, MIIA2 and MIIA3) had 2.2 ± 0.8 (average ± SD) zones and adult male stages had 3.8 ± 0.8 zones. The female juvenile stage (FIIB) had 1.7 ± 0.5 zones and adult females (FIIIA-E) had 3.7 ± 1.0 zones. There were positive relationships between the number of zones and the maturity stage, and between the number of zones and body length. Further knowledge about molting process in the Antarctic krill and a verification of the ageing procedure from krill with a known age is needed before the number of growth zones can be definitely established as an indicator of age. The detection of growth zones in the Antarctic krill will be an important contribution to the understanding of the biology of the species if the zones actually represent annual growth.

In Division 58.4.3a, since 2012, research fishing has been conducted in the research block by two vessels using longlines: Shinsei Maru No. 3 (Japan) and the Saint André (France). The catch limit for Dissostichus spp. is 32 tonnes and the total reported catch up in 2014/2015 was 15 tonnes. A technical problem for the French vessel had shortened the fishing campaign. In this proposal, France and Japan commonly notifies their intention to continue their exploratory fisheries in Division 58.4.3a over the coming years in order to contribute to the tagging program and to achieve a robust stock assessment that would provide advice on a catch limit according to CCAMLR decision rules. This paper aims to present a research plan for 2016/2017 developed under Conservation Measure 41-06. The biomass in division 58.4.3a was estimated during WG-FSA 2015 using the Petersen estimator at 398 tonnes. Despite further developments of CASAL integrated stock assessment models for this division in 2015, geometric mean of Chapman biomass estimators is used for the calculation of stock size in this division in 2015. The developing CASAL model has to assess stock biomass with reliable estimates of IUU removals and to define a maturity key and parameters for the von Bertalanffy growth curve from age readings. The catch limit should remain unchanged at 32 tonnes for 2016/17 to maximize the expectation of tag-recapture.

Exploratory fishing for toothfish (Dissostichus spp.) in Division 58.4.2 began in 2003. In 2015 the fishery was limited to one Korean and one Spanish flagged vessel using longlines and the precautionary catch limit for the exploratory fishery for Dissostichus spp. was 35 tonnes in SSRU E. Only the Korean-flagged vessel undertook research fishing activity with a total reported catch of 11 tonnes. For 2016 a total of five vessels, one each from Australia, France, Japan, Korea and from Spain, have notified their intention to participate in the exploratory fishery. For 2017 France notifies its intention to participate and coordinate the operations of their research efforts with other members in order to achieve a robust stock assessment and define catch limits according to CCAMLR decision rules. This paper presents a proposal for a research plan for 2016/17 developed under Conservation Measure 41-05. The aim is to collect sufficient data to provide an advice on a catch limit according to CCAMLR decision rules. The biomass in the Division was estimated during WG-FSA 2015 using CPUE x seabed analogy. In the absence of an assessment using the CCAMLR decision rules, the catch limit should remain unchanged at 35 tonnes for 2016/17 to maximize the expectation of tag-recapture and the approach of allocation and collaboration between Members should be maintained.

Exploratory fishing for toothfish (Dissostichus spp.) in Division 58.4.1 began in 2003. Robust stock assessment and catch limits according to CCAMLR decision rules remain to be determined for this Division. France notifies its wish to collaborate in this research fishery with the other participants over the coming years in order to participate in the tagging program and achieve a robust stock assessment. The aim is to collect sufficient data to provide an advice on a catch limit according to CCAMLR decision rules. This paper presents a proposal for a research plan for 2016/2017 developed under Conservation Measure 41-11. The biomass for each in the Division was estimated during WG-FSA 2015 using CPUE x seabed analogy. In the absence of an assessment using the CCAMLR decision rules, the catch limit should remain unchanged at 660 tonnes for 2016/17 to maximize the expectation of tag-recapture and the approach of allocation and collaboration between Members should be maintained.