comparisons were made with the structure of a fish assemblage
from a nearby site unaffected by sewage effluent. Total species richness, density and biomass of
fish, decreased at both sites over the 30-year period. An increase in mean trophic level near the sewage
outlet following improvements in water quality indicated that wastewater treatment had another important
effect. This result is consistent with the reductions in food webs supporting pelagic and benthic
fishes that typically accompany decreases in nutrient inputs. Although improvements to wastewater
treatment explained much of the variation in the structure of the fish assemblage at PC, our results also
suggest that fishing and climate change, at both sites.