The inaugural COLTO Depredation Workshop took place in Punta Arenas, Chile, 15-18 March 2016.  Results were an enhanced understanding on the current state of depredation in toothfish fisheries, as well as a vision of what is required in the short-to-medium term to better understand and evaluate depredation.  “Next steps” regarding studying and minimising depredation were established for all toothfish fisheries, and it was agreed that the scientists who participated in the workshop would produce a peer-reviewed paper, encompassing a global review on depredation in high latitude fisheries; and operational guidelines in regards to depredation.

A second depredation workshop is planned for 2018, aimed at presenting how depredation research and mitigation has evolved, and what findings resulted from the issues that were addressed in the inaugural workshop.

Since the workshop, two separate post-doctoral depredation projects have been developed and will begin in October 2016.  The first, a 4-year project covering the Heard Island and McDonald Islands, Kerguelen Islands, and Crozet Islands toothfish fisheries; and the second, a 2-year project covering other toothfish fisheries.

The annual Random Stratified Trawl Survey was undertaken in Division 58.5.2 in the vicinity of Heard Island during April 2016. This paper provides a preliminary assessment of mackerel icefish population structure, abundance and yield for the area of Division 58.5.2 to the west of 79^o 20’ E using standard CCAMLR methods (CMIX and Generalized Yield Model). A large 2+ cohort is dominating the population. These projections indicate that catches of 561 t in the 2016/17 season and 402 t in the 2017/18 season satisfy the CCAMLR decision rules.

In 2014, the Scientific Committee endorsed a proposal from South Africa that the Secretariat be tasked with developing a proposal for funding support from the Global Environment Facility to build capacity among GEF-eligible CCAMLR Member countries to strengthen their participation in CCAMLR (SC-CAMLR-XXXIII, paragraph 10.30).  This report updates CCAMLR Members on developments during 2016. 

In 2016, the USA and New Zealand began a collaborative initiative to describe Antarctic toothfish (Dissosticus mawsoni) movement and habitat preferences in the Ross Sea (Subarea 88.1) using pop-off satellite archival tags (PSAT) tags. Fish were tagged as part of research longline efforts in the southern shelf and northern seamount regions. A total of 10 PSAT tags of two tag types were released on the southern Ross Sea shelf in the austral summer, and 5 PSAT tags were released on the northern seamounts in the austral winter, for a total of 15 PSAT releases. All fish were also double tagged with standard CCAMLR dart tags. Releases were distributed across 5 different SSRUS within Subarea 88.1.

The frequency distribution of oocytes diameter and relative fecundity (FR) of 4 notothenioids (Chaenocephalus aceratus, Chaenocephalus gunnari, Notothenia rossi and Pseudochaenichthys georgianus) was carried out, in females collected during a fishery research survey around the Elephant Island and South Orkney Islands), between 21th January and 14th February 2015. Measurement and oocyte counting were carried out using an image analyzer in sub-samples of ovaries at different stages of development, while the determination of RF was performed by a gravimetric method. Five were the main distinctive finding derived from this study: (i) in mature ovaries of all species immature oocytes or pre-vitellogenic appeared clearly separated from the most advance mode of mature oocytes; (ii) in hydrated ovaries the less developed group showed a polymodal pattern in C. aceratus and N. rossi; (iii) in hydrated ovaries of P. georgianus a trimodal structure was visible, containing immature oocytes (<0.9 mm), mature (range: 1.16 to 1.86 mm) and ovulated oocytes (range: 4.5 to 5.387 mm; average FR: 3 oocytes·g-1), respectively; and (iv) the FR tended to be higher when estimates were derived from mature ovaries (range: 5-12 oocytes·g-1) than form hydrated ovaries (range: 1-2 oocytes·g-1). The results confirm these species have a group-synchronous ovarian organization, but suggest there may be variables strategies, without dismissing is serial spawning, particularly due to the physical limitations that would impose the abdominal cavity to spawn large eggs, a characteristic ecological trait in notothenioid. Additionally, the occurrence of hydrated ovaries suggests reproductive activity in summer season for species commonly spawning in autumn and winter, which may be indicative of an either longer spawning season or alternatively is associated to some environmental factor that triggered an anticipation of the spawning season.

This paper submits the results of the acoustic cruise made in the austral summer of 2016. The survey delivers the bottom bathymetry, the geographic distribution of krill concentrations, and the presence of fish shoals in 1,500 nautical miles over the shelf and the continental slope (100-500 m), around Elephant Island and South Orkney Islands. Krill concentrations are described, as well as those of mackerel icefish (Champsocephalus gunnari), the latter representing the most abundant fish species in the research, besides other finfish species in the area. The mackerel icefish was found between 160 and 449 m depth, associated to steep bottom, showing demersal characteristics during the day and semi-pelagic overnight. During the darkness hours the mean determined depth in the schools was 207.1 ± 62.6 m around Elephant Island and 219.4 ± 55.8 m in South Orkney Islands.

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 with Chapman method using “tagr” Package and single population approach at 603 tonnes. 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 and while a CASAL integrated stock assessment model is being developed.

Marine debris data were collected at Bird Island and King Edward Point, South Georgia, at Signy Island, South Orkneys and at Goudier Island, Antarctic Peninsula for the period April 2015 to March 2016. Surveys of beached marine debris at Bird Island recorded a total of 56 and 123 items during winter (April to September 2015) and summer (October 2015 to March 2016) respectively. One item of beached debris (a piece of lumber) was recorded at Signy Island (operational during summer only; 16 November 2015 to 1 April 2016). 12 items of beached marine debris were recorded at Goudier Island (operational 15 November 2015 to 4 March 2016), which is the highest number since recording began in 2010/11. Entanglements of two sub-adult Antarctic fur seals and one juvenile elephant seal were observed at Bird Island, with three instances of entangled fur seals observed at King Edward Point, and no marine mammal entanglements observed at Signy Island or Goudier Island. In total, 127 items of marine debris were found in association with seabird colonies at Bird Island, most commonly in association with wandering albatrosses (65 items). Two incidences of entangled adult wandering albatrosses and one entangled snowy sheathbill were recorded; all were removed successfully. There were no observed incidences of hydrocarbon soiling at any site during the reporting period. Overall, the occurrence of beached marine debris was below the long-term mean at both Bird Island and Signy Island. The incidence of marine mammal entanglements was below the long-term mean at all sites surveyed. Debris associated with seabird colonies was below the mean level for wandering albatrosses and black-browed albatrosses, but above the mean for grey-headed albatrosses and giant petrels.

Our knowledge of seabird assemblage composition and abundance at-sea is limited by the availability of vessel platforms. Fishing vessels is an alternative to dedicated research vessels. Besides, it is important to document potential interactions between fishing vessels and seabirds and to discern potential biases in seabird assemblages that fishing operations could cause. Here we document seabird assemblages during research trawl for finfish around Elephant and South Orkney Islands during summer. There were a total of 13 species recorded, with only two species only found at Elephant or South Orkney Islands. Mean species richness per set during fishing operations was 4-5, with a mean abundance of 139 birds at Elephant and 40 birds around South Orkney Islands during net hauling. Main species sighted were Cape petrel, Black-browed albatross, Giant petrel and White-chinned petrel, which were more abundant at the stern rather than the bow of the vessel. The information was collected as part of the project "Finfish distribution and abundance in Subareas 48.1 and 48.2" developed by the Pontificia Universidad Católica de Valparaíso on board the fishing vessel Cabo de Hornos, between January 21 and February 14, 2015.

During a CCAMLR endorsed fishing survey on board the Chilean trawler ‘Cabo de Hornos’ around the South Orkney Islands and Elephant Island, a trained marine mammal observer conducted a distance sampling survey for cetaceans along track. During 10 survey days, 463.1 km were covered on effort. A total of 44 fin whale (Balaenoptera physalus) groups comprising 61 individuals were recorded on effort, and a total of 28 humpback whale (Megaptera novaeangliae) groups comprising 47 individuals. A single sei whale (Balaenoptera borealis) was also recorded. Off effort, e.g. during fishing operations, 35 sightings of mainly mixed-species groups and feeding aggregations of large whales were observed, comprising 217 individuals, including calves of both humpback and fin whales. The preliminary results of the survey show that the areas around the Southern Orkneys and Elephant Island are important feeding grounds for fin-, humpback and, to a lesser extent, sei whales. If any fishing effort is to be undertaken in these areas, no disturbance within these comparably small areas of high animal density should be tolerated. We recommend standardising any future research cruise by incorporating a set of synchronized video cameras to the bow and stern section of the ship to assess any potential behavioural response to allow further insight into interactions with fishing activities and to help quantify any disturbance or nuisance imposed on cetaceans, seals and birds.