CCAMLR

In response to the request from SC-CAMLR-XXXIV, the Secretariat has provided area-specific information on IUU activity that could be incorporated into the relevant Fishery Reports.

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.