CCAMLR

This report presents results from a pilot study to investigate the use of acoustics to estimate middle trophic level prey organisms (e.g., krill and mesopelagic fish) in the Ross Sea. Single frequency (38 kHz) acoustic data were available from New Zealand longline vessels participating in the exploratory fishery for toothfish in 2002–03 and 2005–06, and multifrequency (12, 38, and 120 kHz) acoustic data were collected from the research vessel Tangaroa during a voyage to the western Ross Sea in February–March 2006. Analyses were carried out to assess data quality, describe different mark types, and quantify spatial and vertical distribution of acoustic backscatter in the upper 1000 m of the water column.
There were clear spatial patterns in the amount and type of mesopelagic backscatter observed. There was much more backscatter in the upper 1000 m and a wider variety of mark types north of 67° S. Common mark types in the northern region included a surface layer at less than 50 m depth, schools and layers centred on about 200 m and 400 m depth, and a diffuse deep scattering layer centred at 750 m depth. Average acoustic density was lower south of 70º S, and most of the backscatter was from schools and layers shallower than 100 m. Near bottom marks were associated with areas shallower than 1000 m on the Ross Sea shelf edge. In general, the amount of backscatter observed in the Ross Sea was much lower than that observed in shelf areas off New Zealand (Chatham Rise and Campbell Plateau).
Little direct information is available on the species composition of different mark types in the Ross Sea. However, different acoustic responses across the three frequencies available on Tangaroa provided some clues about the likely identity of the key scatterers. Marks shallower than 100 m depth were typically much stronger on 120 kHz than on 38 kHz, and weak on 12 kHz. This type of acoustic response is typical of krill or other large zooplankton. Schools and layers at 200–400 m depth showed a more consistent response across all three frequencies and may have been associated with small fish. This study identified key areas and mark types for further research, including directed sampling, and showed how fishing vessels could be used to opportunistically collect acoustic data.

A standardized krill net sampling survey was conducted in the Lazarev Sea (Subarea 48.6) in December 2005. Krill densities were low in the Lazarev Sea. No substantial day/night differences were observed in the catches. Spatial distribution of krill density and size/age classes is discussed for the Lazarev Sea. Recruitment indices were calculated for one-year-old (R1) and two-year-old krill (R2), showing high values for both recruitment indices. New information is given on the development of maturity stages in the early phase of the spawning season.

Cape fur seals (Arctocephalus pusillus) were estimated to kill some 6 000 Cape gannet (Morus capensis) fledglings around Malgas Island in the 2000/01 breeding season, 11 000 in 2003/04 and 10 000 in 2005/06. This amounted to about 29%, 83% and 57% of the overall production of fledglings at the island in these breeding seasons, respectively. Preliminary modelling suggests this predation is not sustainable. There was a 25% reduction in the size of the colony, the second largest of only six extant Cape gannet colonies, between 2001/02 and 2005/06. There has been a large increase in predation by Cape fur seals on seabirds around southern African islands since the mid 1980s, coincidental with both an increase in the seal population and altered management of the islands. At Malgas Island, most gannet fledglings were killed between 10h00 and 18h00, the period when most are in the water around the island, from mid January to mid March, the main fledging period. The Cape gannet is classified as Vulnerable.

We used radio telemetry and observations to study the activity patterns and behaviour of gentoo penguin chicks during their “fledging period”; defined as the time between a chick’s first trip to sea and its final dispersal from the breeding colony. Our study was conducted at a colony of approximately 2500 breeding pairs of gentoo penguins in Admiralty Bay, King George Island, South Shetland Islands during the 2004-05 austral summer. Gentoo penguins exhibited delayed dispersal of young coupled with extended parental provisioning, behaviours not observed in other Pygoscelis species. Chicks took their first trip to sea at a mean age of 70 days of age, before finally departing the colony at an average age of 82 days. During this fledging period, individual chicks made an average of five trips to sea. Trip duration increased significantly with chick age as trips to sea becoming more similar to adult foraging trips in both timing and duration. Behavioural observations confirmed that many chicks were still being fed during this fledging period, with parental feeding behaviours most often observed in the late afternoon to evening hours. We hypothesize that these behaviours not only provide the opportunity for chicks to gain experience at sea prior to dispersal, but also allow them to develop foraging behaviours and skills at this time. These results have implications to differences in life history traits and population trends among gentoo penguins and their congeners, the Adélie and chinstrap penguins.

Bycatch of small (

This paper summarises the notifications received from Members intending to particpate in the krill fishery in Area 48 in the 2006/07season.

This report on the krill fishery in Area 48 has been prepared in a format similar to the “Fishery Reports” developed by WG-FSA in 2004. As reported to the CCAMLR Secretariat, 7 vessels from 5 Contracting Parties are fishing for krill in Area 48 in the 2005/06 season, and these vessels have taken 64415 t of krill to date. Two CCAMLR scientific observers have been deployed. The preliminary estimate of the total catch of krill for the season is approximately 97090 t. This compares with 127035 t of krill reported in the STATLANT data for 2004/05. All fine-scale data from Korea for 2004/05 are overdue, as they are currently still held on board the vessels. Every effort will be made to submit these data as soon as the vessels return to port.
The report includes: Availability of fishery and observer data; Time series of catch by season, Contracting Party and small-scale management unit; Species composition of by-catch; Occurrence of incidental catches of seabirds and mammals; Development of measures of overlap between the krill fishery and krill predators; Consideration of the Conservation Measures in force in the fishery. Reference information on stock and areas, and parameters used in stock assessment are also included.

The CCAMLR Ecosystem Monitoring Program (CEMP) uses indices derived from data on indicator species collected by standard methods in the three Integrated Study Regions of the Convention Area. Each year the Secretariat updates the standardised index values and provides a summary of trends and anomalies in these data. This report covers predator indices only.
Data were submitted by 8 Members for 10 sites and 13 different CEMP parameters for the 2005/06 season. No data were submitted from Admirality Bay, King George Island, and Ross Island. Only population counts were submitted for Edmonson Point.
The development of an ordination method, with guidance from WG-EMM and consultation with experts, is proposed as a main priority for the forthcoming intersessional period.