The long-term benthic disturbance experiment (BENDEX) was started on the eastern Weddell Sea shelf off Austasen (Antarctica)
during ‘Polarstern’ cruise ANT XXI/2 in December 2003 to simulate the impact of grounding icebergs on the seabed and follow
the steps and timescales of recovery of disturbed benthos and demersal fish communities. Here, we report the basic approach
and first results for this experimental field study. By means of 11 densely-placed hauls with a modified bottom trawl, a seabed
area of approximately 100 × 1000 m was artificially scoured to inflict a similar damage to the benthic habitats as a grounding
iceberg. Before the disturbance event and 11 days after it, the seafloor communities were sampled (invertebrate assemblages
by multibox corers, the fish fauna by trawl hauls) and comparatively analyzed. Sediment texture and chemistry was not significantly
altered by the heavy disturbance inflicted by repeated trawling, whereas the fauna was negatively affected. Invertebrate benthic
biomass was drastically reduced by a factor of 10, while mean abundances were only slightly reduced. Demersal fish biomass
and abundance were slightly but not significantly smaller after the disturbance. Effects of disturbance became more evident
in the composition of the fish fauna, with
Trematomus pennelli and
T. hansoni being dominant at disturbed sites, whereas
Chionodraco myersi was the dominant species in trawl catches from undisturbed stations.
Keywords Macrobenthos - Demersal fish - Antarctica - Disturbance