Distribution and abundance of Antarctic krill in the vicinity of Elephant Island during the 1994 austral summer

The distribution and abundance of Antarctic krill (Euphausia superba) were estimated from four acoustic surveys conducted in the vicinity of Elephant Island, Antarctica, from mid-January to mid-March, 1994. The first and last surveys covered approximately 15,000 n.mile2 around Elephant Island and the eastern end of King George Island; the second and third surveys covered approximately 2100 n.mile2 immediately north of Elephant Island. During the first survey, the highest densities of krill were mapped north of King George Island and over a broad band northwest of Elephant Island. For a portion of the survey area centered on Elephant Island (aproximate1y 12,000 n. mile2), biomass was estimated to be 401 X 106 t. Five weeks later highest densities of krill were mapped north of Elephant Island and biomass in the same survey portion was estimated to be 359 X 106 t. During the second and third surveys high densities of krill were mapped in the shoal waters to the north of Elephant Island; biomasses were estimated to be 87 X l06 t and 97 x 106 t, respectively. Average bill densities were the lowest observed during the last five years of AMLR surveys in the Elephant Island study area and one-fifth of the 1990-1992 average density. In spite of the low krill densities, the reproductive success of land-breeding predators did not appear to be adversely affected.