CCAMLR

This document is to announce our intension to hold ‘Workshop on krill culturing techniques’ at Port of Nagoya Public Aquarium, Japan, in September 2002. Port of Nagoya Public Aquarium recently succeeded in reproducing and raising Antarctic krill up to juvenile stages under an artificial condition. Several research groups in the world are also independently developing their culturing techniques. Developing techniques of culturing krill in large number is thought to be a major break through for further understanding of krill biology. However, these achievements are not effectively gathered to provide a standard methodology. The aim of the workshop is to share the knowledge to date about the methodology of krill culturing and experiments, and contribute to the future experimental studies on Antarctic krill.

Four Japanese krill fishing vessels operated in Area 48 during the 1999/2000 split year. In Subarea 48.1, the operation started in December and lasted until June. In Subarea 48.2, operation took place in December, March, and May to June. In subarea 48.3, operation took place only in June. Trawling positions, CPUEs and body length of Antarctic krill during the period is described. The krill length frequency distribution was further compared with those obtained by the CCAMLR international observer undertaken at the same time, and they resulted in good agreements. The discussion was extended to the possibility of intra-annual variability of two krill stocks (Antarctic Peninsula and Weddell Sea stocks).

Inter- and intra-annual variability of commercial krill trawling positions for the 1980/81 to 1999/2000 seasons in the area to the north of South Shetland Islands were analyzed in relation to biological and environmental factors. Commercial fishing perations concentrated on the outer shelf in the early 1980’s, along the shelf slope in the mid- to late 1980’s, and were highly variable, from the shelf across to the outer shelf in the early to late 1990’s. Intra-annual variation of trawling positions showed a general pattern starting from the outer shelf, and proceeded towards the shelf later in the season. Trawling positions seemed to be primarily governed by the distribution of larger mature krill, especially at the beginning of the operation each season. In summer, biological factors that affect product quality such as salp abundance and the proportion of green krill , also seemed to have an increasing effect on trawling positions.. Ice conditions for the recent fishing period were also demonstrated to have an effect.

There are two general kinds of polynya (an ice-free area within sea ice borders), coastal polynya and open ocean polynya, in the Southern Ocean. Polynya accelerates oceanic and atmospheric processes by exposing the surface of ocean to the atmosphere. Additionally, we think that the coastal polynyas influence biological activity in the winter and spring season. However, there are no minute reports on the place, time and shape of the coastal polynyas. Accordingly, we pursued the transition of the coastal polynyas using satellite image data of sea ice concentrations by the NSIDC (National Snow and Ice Data Center, USA).
Time series of polynyas extent per a day were calculated from 1978 to 1998 and converted into the yearly mean. The time series of the yearly mean in the whole Antarctic Ocean are trending upper after the latter half of the 1980s. The time series around the Antarctic Peninsula are trending like a pulse wave. In the whole Antarctic Ocean, peak years of polynyas extent are in the 1981/82 (from July 1981 to June 1982), 1991/92 and 1995/96. In the Antarctic Peninsula area, peak years are in 1980/81, 1987/88 and 1992/93.

The austral summer 2000/01 marked the fourth full season of land-based predator research at Cape Shirreff, Livingston Island, Antarctica. Results of the monitoring activities undertaken in support of CCAMLR WG-EMM, are summarized in the report

Our long-term seabird research at Admiralty Bay has documented annual variability in the life history parameters of the breeding biology and ecology of Adélie, gentoo, and chinstrap penguins. Long-term data acquired on these species including: survival and recruitment, population size and breeding success, diets and foraging ecology, provide clear evidence linking offshore biological and physical processes to their effects on dependent predators in the Southern Ocean. Our most recent results present a conceptual model linking increasing temperatures and decreasing sea ice cover in the Antarctic Peninsula region to declines in krill and penguin populations. Winter temperatures in the Antarctic Peninsula region have increased 4-5°C over the last 50 years (Smith et al. 1996, 1999), affecting the periodicity of sea ice cover in the region. This climate change, and the associated reduction in winter sea ice cover, has profoundly impacted the Antarctic, krill-based food web (Loeb et al. 1997, Smith et al. 1999, Trivelpiece and Trivelpiece, in prep.).

This information paper is a compilation of websites and publications on Marine Protected Areas (MPAs). The paper is intended as an educational guide and contains an array of national, international, academic, governmental, and non-governmental sources. The list is not exhaustive and should be considered as a starting point for further research.

This paper presents vertical distribution of temperature, salinity, density and flow across the Drake Passage. The seventh Antarctic Ocean Survey cruise by the R/V Kaiyo Maru of the Japanese Fisheries Agency was conducted in the waters around the Antarctic Peninsula in 199/95 austral summer season. In the survey, oceanographic observations were carried out along the north-south line from 56-21 S, 66-37W to 61-49S, 58-28W across the Drake Passage from 1 to 9 December 1994. The Polar Front recognized by a steep gradient in temperature was located between 58-00S and 59-00S. The Antarctic Surface Water, defined as water temperature 0°C or less, was distributed from 58-40S to the southernmost station, 61-49S. The flow across the line was eastward through the whole except the weak flow through some sections. The maximum speed of the flow was approximately 30cm/s corresponding to the Polar Front zone. Upwel1ing of the Warm Deep Water was suggested in the costal water north of the South Shetland Islands.

CCAMLR Conservation Measure 32/X sets a 1.5 million metric ton precautionary catch limit on krill (Euphausia superba) in Statistical Area 48. The measure also implies the application in future of precautionary limits could be applied to subareas or local areas. Nine alternative methods of determining subarea or local area krill catch limits are evaluated relative to six criteria: (i) the degree to which information on biological relationships is considered, (ii) the cost of data collection, (iii) the reliability of required information, (iv) the ease of enforcement, (v) the effects on current fishing patterns, and (vi) the potential for delay in implementing the alternative. An alternative is less likely to adversely impact dependent species (e.g. penguins and seals) if the ecological relationships between krill and their predators are explicitly considered and the potential for delayed implementation is low. Therefore, we consider the following tradeoff to be important: choosing a biologically explicit alternative and delaying implementation, or choosing a biologically unrealistic alternative and implementing a management scheme immediately. We recognize that other tradeoffs may be equally important. Alternatives that allocate the 1.5 million ton limit by evenly dividing the catch among subareas or by using historical catches to set limits can be categorized as having a low potential for delaying implementation, but they ignore information on biological relationships. Alternatives based on protective zones, critical periods, predator censuses, and predator-prey models include large amounts of biological information, but may not be practical in the near future. Alternatives based on continental shelf area, simple pulse fishing, and krill surveys are not biologically explicit and result in delayed implementation. None of the alternatives are categorized as being both biologically explicit and immediately available for implementation. However, two of the alternatives (i.e. protective zones and critical periods) are unsatisfactory only because they would alter current fishing patterns. These two alternatives could be implemented immediately if the CCAMLR Member nations to are willing to tolerate changes in current fishing patterns.

One of the important problems in interpreting CCAMLR-2000 results is how they reflect the krill biomass status, is it high, medium or low at the present time. The comparative analysis of krill biomasses derived from trawl catches was carried out; retrospective data of three Soviet surveys, covering the main part of the CCAMLR-2000 area, were used: RV “Argus” (27.01.84-16.03.84) and RV “Evrika” (11.10.84-14.12.84 and 20.01.88-09.03.88). There were used similar gear (Isaak's Kidd Midwater Trawl) and methods of sampling, but sampling was carried out in the 0-100 m water layer instead 0-200 m in CCAMLR-2000. Krill biomass index calculated for the whole area of Soviet surveys doesn't reveal any significant changes, being in the limit of 15.3-20.3 g/m2. When assuming that changes of average weight density reflect biomass variability, it may be suggested that value of the total krill biomass in the area 48 is quite stable during last seventeen years. It is to be noted however that due to difference in layers sampled during CCAMLR-2000 and Soviet surveys, krill biomass derived from data collected in 80-s may be considered as overestimated comparing CCAMLR-2000 results, the rate of overestimation is unclear. If it is true and level of overestimation is considerably high, we have to admit increase in krill biomass since 80-s, however rate of this increase is impossible to determine on the present stage.