CCAMLR

On the processes to investigate a proper model for understanding the processes that govern the biochemical cycle in Antarctic Ocean, we made a research plan as follows: (1) to develop an OGCM (Ocean General Circulation Model) (2) to develop a one dimensional ecosystem model that can be applied to primary production in Antarctic Ocean (3) to develop an ecosystem model able to describe krill ecology (4) to develop a numerical model to couple the OGCM and ecosystem models (5) to develop a numerical model including the effect of marine mammal consumption and catch of krill (6) to develop the integrated model with the above 5 items.
This year, we have developed a three dimensional regional model off King George Island and Livingstone Island to connect the OGCM developed by CCSR (Center for Climate System Research, University of Tokyo).

This paper summarizes Japanese krill catch data during austral summer in 1993/94 season. Main fishing grounds were persistently formed in the north of Livingston Island throughout the season, and the west of Elephant Island from April to May. CPUEs showed the highest values at the height of summer (early February - early March) in the north of Livingston Island, and April at the west of Elephant Island. Krill with a modal length of 41-45mm were dominant in catches, almost same as the previous season.

The seventh Antarctic research cruise by the R/V Kaiyo Maru of the Japanese Fisheries Agency was conducted in the southwest of the Scotia Sea, especially in the vicinity of the South Shetland Islands from December 1994 to February 1995. The main objective of the seventh research was an oceanographic and ecological survey in relation to the distribution and abundance of the Antarctic krill (Euphausia superba). This document introduces an outline of the contents enforced by the research. Detailed analytical studies are currently in progress.

Water flows in harvestable areas for Antarctic krill (Euphausia superba) on the continental slope and shelf of the South Shetland Islands were examined based on drifting buoy data. Convergent complex eddies were observed in harvestable areas on the shelf, while shear current was observed in those on the slope. Large-scale movements of the buoys suggest krill flux from the South Shetlands into South Georgia or the South Orkneys.

Consistent gender differences in foraging trip durations, feeding localities and diet of breeding Adelie penguins were demonstrated at two widely separated locations over a number of years. Female penguins tended to make longer foraging trips than males, ranged greater distances more frequently and consumed larger quantities of krill, especially when chicks were small. Males tended instead to make shorter journeys to closer foraging grounds during the guard period, and fed more extensively on fish throughout chick rearing. The importance of these results to monitoring programs such as the CCAMLR Ecosystem Monitoring Program (CEMP), their relevance to the energetics of reproduction and their role in the intraspecific partitioning of foraging behaviour are discussed.

The survey design for an integrated biological/physical survey of Division 58.4.1 during January - March 1996 is presented in this paper. Key measurements to be taken during this survey include hydroacoustic determinations of krill distribution and abundance and physical oceanographic sampling along 18 regularly spaced transects from the Antarctic coastline to a distance of 180 n miles. The data on krill distribution and abundance will be submitted to CCAMLR for the purpose of setting a precautionary catch limit on the krill fishery in Division 58.4.1.