Summary
Diurnal variations in the vertical distribution and swarming behaviour of Euphausia crystallorophias at Deception Island (61 degrees South, 66 degrees West) are described. Swarms were present at all times of the day and night. By day swarms were compact and deep, they were dispersed and neared to the surface by night. Significant net avoidance was noted by day. A twenty-fold discrepancy was found between abundance estimated from net hauls and acoustics. This difference is almost certainly because currently used Target Strength (TS) to size relationships overestimate TS and consequently undersetimate euphausiid biomass.
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References
BIOMASS (1986) POST-FIBEX Acoustic Workshop. Frankfurt/M (FRG), BIOMASS Rep Ser 40
Everson I (1982) Diurnal variations in mean volume backscattering strength of an Antarctic krill (Euphausia superba) patch. Plankt Res 4:155–162
Everson I, Bone DG (1986) Effectiveness of the RMT8 system for sampling krill (Euphausia superba) swarms. Polar Biol 6:83–90
Fischer W, Hureau J-C (eds) (1985) FAO Species Identification Sheets for Fishery Purposes. Southern Ocean (Fishing areas 48, 58 and 88) (CCAMLR Convention Area), vol 1. Prepared and published with the support of the Commission for the Conservation of Antarctic Marine Living Resources. FAO, Rome, 232 pp
Heywood RB (1985) Environmental conditions in the Antarctic Peninsula area of the Southern Ocean during the Anglo-German Joint Biological Expedition, February 1982. Meeresforschung 30:220–239
Hubold G (1985) Stomach contents of the Antarctic Silverfish Pleuragramma antarcticum from the Southern and Eastern Weddell Sea (Antarctica). Polar Biol 5:43–48
John DD (1936) The Southern species of the genus Euphausia. Discovery Rep 14:195–319
Kalinowski J, Witek Z (1980) Diurnal vertical distribution of krill aggregations in the Western Antarctic. Pol Polar Res 1:127–146
Kittel W, Stepnik R (1983) Distribution of Euphausia crystallorophias, E. figida, E. triacantha and Thysanoessa macrura (Crustacea, Euphausiacea) in the Southern Drake Passage and Bransfield Strait in February and March 1981. Pol Polar Res 4:7–19
Kristensen A (1983) Acoustic classification of zooplankton PhD Dissertation, University of Trondheim (published as Report STF44 A83187 at Electronic Research Laboratory, Department of Engineering)
Marr JWS (1962) The natural history and geography of the Antarctic krill (Euphausia superba Dana). Discovery Rep 32:33–464
Roe HSJ, Shale DM (1979) A new multiple rectangular midwater trawl (RMT1+8M) and some modifications to the Institute of Oceanographic Sciences RMT1+8. Mar Biol 50:283–288
Semeoto DD (1980) Quantitative measurements of Euphausiids using a 120 kHz sounder and their in situ orientation. Can J Fish Aquat Sci 37:693–702
Siegel V (1986) Investigations on the biology of Antarctic krill, Euphausia superba; in the Bransfield Strait and adjacent areas. Mitt Inst Seefisch Hamburg 38:1–244
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Everson, I. Some aspects of the small scale distribution of Euphausia crystallorophias . Polar Biol 8, 9–15 (1987). https://doi.org/10.1007/BF00297158
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DOI: https://doi.org/10.1007/BF00297158