Abstract:

Surveys on ocean environment,particularly on krill ecology,were carried out twice in the Prydz Bay area by the Sixth and Seventh Antarctic Explorations during the 1989/1990 and 1990/1991 Antarctic summer.A colour fishfinder Atlas 792 DS made in Germary was used to search Antarctic krill in the whole course.On the basis of the images recorded by the fishfinder and the results obtained from sampling stations,the concentration of krill off the Prydz Bay area was very scarce in 1989/1990.According to the images obtained from the investigation of an area of 6.75×10 5km 2 off the Prydz Bay area (62°-69°S,68°-108°E) conducted by the Seventh Antarctic Exploration from 27th Dec.,1990 to 11th Jan.,1991 and the analyses of the distribution of krill in the surveyed areas,the results show that the horizontal distribution of krill in the surveyed waters can be divided into three areas(i.e.61°-65°S,103°-108°E;63°30′-64°30′S,84°-86°E;62°-65°S,72°-73E°);most of the krill aggregation were in depth of 30-60m and the central area of krill concentration undulated in the layer of 40 meters in 24 hours a day,with about 10 meters in range of fluctuation. Also according to the image records from the Seventh Antarctic Exploration and aimed fishing sampling of krill by IKMT(Isaus-Kidd Midwater Trawl),2.2×10 8 tons of standing crops and 32.59 t/km 2 of density of distribution were hydroacoustically estimated using WT-2 type of image processing system and special software.