THE EFFECT OF SEWAGE AND NATURAL SEASONAL DISTURBANCES ON BENTHIC MACROFAUNAL COMMUNITIES IN FITZROY BAY, WELLINGTON, NEW-ZEALAND

Benthic macrofauna were sampled on 6 occasions over a 14 month period from Fitzroy Bay, Wellington, New Zealand to assess the effects of an existing sewage effluent discharge on these organisms and to determine natural seasonal fluctuations in community structure within the vicinity of a proposed new ocean outfall. Results of Abundance/Biomass Comparison (ABC), Cluster, and Multi-Dimensional Scaling analyses indicated that only benthic communities within a 500 m radius of the present sewage outfall were affected by the discharge. However, seasonal data indicated that most sites within Fitzroy Bay were disturbed on at least one occasion during the sampling period. The data suggest that ABC analyses should be conducted over several seasons to provide a more accurate assessment of pollution-induced and/or natural physical and biological disturbance.