CCAMLR

The distribution, density and length composition of krill in commercial concentrations were investigated in the regions of South Shetland, Elephant, South Georgia and South Orkneys in spring and summer 1997-1999. The concentration densities varied with area and season. The densest concentrations were found near South Shetland. Concentrations at night were several times less dense than those during the day. Between February and April the concentration density increased, and in May and June it decreased. Since during the period of February - June day illumination progressively becomes shorter it must be assumed that there are other factors besides illumination which have an impact on the degree of krill concentration. The internal structure of the concentration was very diverse and the mean density varied from 11 to 31,370 specimens * m-3. At night, the krill concentrations were scattered throughout the water, however, no clear evidence of vertical migrations was found. Between February and April, the night concentrations occurred in much shallower waters than during the day, while in May and June they occurred at the same depths as the day concentrations or sometimes even deeper. The day concentrations between February and April, ocuured in shallower waters, while between April and June they were found in deeper waters. The size structure of the krill was diverse during all periods and in all areas, however, a decrease in krill size was observed as the season progressed.

There is a long-term interest in the population genetics of Antarctic krill species because of their ecological end economic importance. The possibility that there are distinct genetic stocks of these species would affect the design of management strategies for conserving them. A recent resurgence of interest in identifying distinct stocks of swarming krill species has been driven by the development of genetic technologies that are more sensitive to subtle population structure than older methods. Previous studies of the population genetics of the Antarctic species Euphausia crystallorophias, E. superba and the boreal species Meganyctiphanes norvegica that used allozymes found no evidence for population structure. More recent investigations using sequence variation in mitochondrial DNA (mtDNA) did indicate genetic differentiation between samples taken from different parts of the each species' range. However, the underlying assumption of these studies that differentiation between samples is caused primarily by restricted gene flow between widely separated sampling sites may be incorrect. Our recent study of E. crystallorophias mtDNA variation shows that there is significant genetic differentiation between samples taken within one region. This has important implications for the design of future studies of krill population genetics, which must be able to accommodate this variance component as well as variance attributable to differences between regions. Genetic differentiation between stocks of krill in different regions can therefore not be adequately assessed unless multiple samples are taken from each region.

Monitoring of the sea surface temperature (SST) in Subarea 48.3 on satellite data (GOES-E, Meteosat), use of in situ data and the further analysis of the SST maps, maps of the SST anomalies and dynamics provide strictly special, but constant information on hydrological situation in the survey area. Analysis of this situation based on data obtained in expeditions, as well as literature and the CCAMLR materials could allow us to assess, with a certain degree of reliability, a potential situation of krill fishery in Subarea 48.3 for the entire coming year already by the summer season onset. Reliability of the krill fishery forecasts could be judged only by actual results of fishing activities under various hydrological conditions. This work is an attempt to perform such an analysis using a certain array of materials obtained in 1989-1991 and 1999-2001.

A net sampling survey was carried out for krill in an established standard station grid around Elephant Island during 27 January to 4 February 2001. Results show a spatial separation of the juvenile and the spawning stock. The station grid was extended to the south, where a large proportion of small size classes, one year old juvenile krill was found. Krill density was significantly higher than during the past years (between 198 and 230 krill 1000 m-3 , i.e. between 40 and 46 m-2 or 11.3 g m-2). The proportional recruitment index for the entire survey area for the 1999/2000 year class was R1 = 0.573, and the absolute index was RI1 = 131.4 * 1000 m-3 , which is among the highest values for the past 20 years. The high krill abundance and the high recruitment index reflect the end of a succession of years with poor recruitment success. The maturation index (G, according to gravid stages), which is discussed as an indicator for a successful spawning season, was G = 0.99, indicating an early initiation of the spawning season. This is thought to be the first step for a successful spawning event and a later potential recruitment success of the 2000/01 year-class. The spatial extent of the station grid is discussed in the light of a representative coverage of the stock and the estimated recruitment index.

In 2000, WG-EMM requested that the Secretariat review the historical development of CEMP indices and ecosystem assessments (Table 3 and paragraph 3.55). The following paper provides a starting point for such a review, as well as a conceptual approach which may provide a framework for a set of reference documents which could be held electronically on the CCAMLR website and/or on CDROM.

In 2000, WG-EMM requested that the Secretariat take on the responsibility of compiling the documentation of the krill yield model (Table 3 and paragraph 2.110). The following paper provides a starting point for such documentation, as well as a conceptual approach which may provide a framework for a set of reference documents which could be held electronically on the CCAMLR website and/or on CD-ROM.

This paper reviews information from krill fisheries operating in the CCAMLR Convention Area during the period July 1999 to June 2001. During that period, 14 vessels targeted krill in Area 48 during the 1999/2000 season (July 1999 to June 2000). A total of 104259 t of krill was caught, of which 69954 t were taken from Subarea 48.1, 28649 t from Subarea 48.2, 4671 t from Subarea 48.3, and 985 t from within Area 48 (subarea not specified). Between July and November 2000, 11 vessels targeted krill in Area 48, and the total catch of krill reported during that period was 30175 t. The 2000/01 fishing season for krill began on 1 December 2000 and ends on 30 November 2001. The total krill catch reported to date (17 June 2001) for the 2000/01 season is 45223 t; 9 vessels are believed to be fishing. No fishing was reported in Areas 58 and 88.
At the request of SC-CAMLR-XIX, a draft Fishery Plan for the krill fishery is also presented as a means of refining the procedure and generating future discussion.

This paper summarises some of the main tasks which the Secretariat has undertaken over the past year in support of WG-EMM. The outcome of these tasks are outlined in table format. Where required, detailed information is provided in meeting papers

The CCAMLR Ecosystem Monitoring Program uses indices derived from data on indicator species and the environment collected by standard methods within the three Integrated Study Regions of the Convention Area. Standardised index values are re-calculated each year as new data become available, and trends and anomalies in these data are presented.

In response to the debate at WG-EMM-99 about the development of the ecosystem approach within CCAMLR. The Secretariat prepared a review of the various tasks initiated at WG-EMM-95 and later meetings (WG-EMM-00/29). The Working Group requested that the review should be updated annually. The 2001 review covers meetings of WG-EMM from 1995 to 2000.