TITLE:    Palmer LTER: Overview of krill acoustic studies and results from the
          Antarctic Peninsula grid
AUTHOR:   Cathy M Lascara, Eileen E Hofmann, Robin M Ross, and 
          Langdon B Quetin
Palmer LTER Contribution #16
ANJ 1993  V28(5) pg 212-214

Several research programs (e.g. BIOMASS and CCAMLR) have shown that
bioacoustics is an effective tool for quantitatively mapping the abundance of
Antarctic krill (Euphausia superba).  The Palmer LTER has included acoustical
measurements as part of the multi-disciplinary sampling conducted at stations
within the large-scale peninsula grid, which covers a coastal region
(approximately 900 km by 200 km) west of the Antarctic Peninsula (Waters and
Smith, 1992).  The acoustic information is used to characterize the spatial
and temporal distribution of Antarctic krill, which is one of the key species
of the LTER program (Ross and Quetin, 1992).
This overview describes the methods of collection and post-processing of
acoustical measurements and presents preliminary results from the 1993 field
season.  Replicate acoustic tows (2-3) are made over short distances (1-2 km)
centered on each grid station and are concurrent with zooplankton or nekton
net tows.  This approach provides acoustic sampling that is coincident with
other data collected at the stations, e.g. hydrographic and primary production
measurements, and allows local and regional variability in the krill biomass
and distribution to be correlated with other habitat characteristics.