RECOVERY OF BENTHIC COMMUNITIES AT MACQUARIE-ISLAND (SUB-ANTARCTIC) FOLLOWING A SMALL OIL-SPILL

Intertidal communities at Macquarie Island (sub-Antarctic) were re-eva luated seven years after a small oil spill resulting from the groundin g of the ''Nella Dan'', and six years after the first assessment of bi ological impact. Sampling was conducted to evaluate community structur e in three zones of the exposed rocky shore (upper red, kelp, and lowe r red) and in samples of Durvillaea antarctica holdfasts. There were n o significant differences between the community structure in oiled and control locations in any of the three shore zones, but holdfast macro faunal communities at oiled sites still showed evidence of impact. Hol dfast community-structure in samples from heavily oiled sites showed m oderate levels of recovery, with increased abundances of species which were considered sensitive to the oiling in the first post-impact stud ies and decreased abundances of opportunistic polychaete and oligochae te worms. In contrast, samples collected from the moderately oiled loc ation at Secluded Bay showed little evidence of recovery. Holdfasts at this site were filled with sediment containing traces of diesel oil, and the macrofaunal community was dominated by opportunistic worms. Th is study clearly indicates that even small incidents of anthropogenic perturbation can have long-lasting consequences for marine communities at Island.