OCCURRENCE OF CYCLOPOID COPEPODS AND FECAL MATERIAL IN THE HALLEY-BAYREGION, ANTARCTICA, DURING JANUARY FEBRUARY 1991

Faecal material and cyclopoid copepods were collected during the exped ition ANT IX/3, in the Halley Bay area (Weddell Sea, Antarctica), betw een January and February 1991. Faecal material comprised pellets produ ced by krill, copepods, ostracods and appendicularians. Cyclopoid cope pods were represented by two genera, Oithona and Oncaea. In the Halley Bay area, higher concentrations of krill faecal material (420.9 mm3 m -2) and chl.-a (39.3 mg m-2) were found within the upper 200 m of the water column of the polynya than in ice-covered open-ocean areas (58.2 mm3 m-2 and 25.5 mg m-2, respectively). At an ice-drift station, high concentrations of krill faecal strings under fest-ice were found. In addition, similarities between diatom assemblages in the pack-ice alga e and krill faecal strings contents suggest an active utilization of i ce-algae by krill populations. Sedimented material collected at 50 m d epth by a sediment trap was dominated by krill faecal strings. Content s of small oval pellets (of probable cyclopoid copepod origin) resembl e those of krill faecal pellets suggesting that coprophagy was involve d. This suggestion is supported by: (1) The small quantity of food par ticles (other than krill faecal matter) available in the water column (< 0.3 mug chl.-al-1). (2) The negative in situ correlation between kr ill faecal strings and cyclopoid copepods. (3) The structure of cyclop oid copepod buccal appendages, which are more adapted for raptorial fe eding.