Characterization of present biological conditions in the intertidal community across Howe Sound, British Columbia

Howe Sound is a Pacific Northwest fjord located north of Vancouver, British Columbia. This fjord has been impacted by effluents from several industries including two pulp mills and a copper mine. After Environment Canada undertook more stringent enforcement on environmental standards in the 1980s, the Britannia copper mine and the Woodfibre pulp and paper mill were shut down. Historical data from the intertidal community indicate that recovery of the ecosystems in these areas has been minimal, particularly at sites in close proximity to industrial activities. The goal of this study was to begin a characterization of several present biological conditions in the intertidal community across Howe Sound. Six sites were selected and grouped based on degree of exposure to industrial activities. High exposure sites included Britannia Beach, Darrell Bay and Port Mellon, while moderate exposure sites included Porteau Cove and Lions Bay. Chaster bay was selected as a reference site for this study. Two biomarkers of exposure; ethoxyresorufin-O-deethylase (EROD) and metallothionein (MT) were measured in mussels to assess the availability of polyaromatic hydrocarbons and metals at these sites. When compared to the Chaster Bay reference site, EROD activity was significantly higher in mussels collected from the two high exposure sites (Britannia Beach (~2.1 increase) and Port Mellon (~1.5 increase)) and the two moderate exposure sites (Porteau Cove (~1.8 increase) and Lions Bay (~1.6 increase). MT levels were significantly higher in mussels from the Britannia Beach (~4.2 increase), Darrell Bay (~2.8 increase) and Porteau Cove (~2.4 increase). Results from another ecological bioindicator (giant kelp) showed that germination rates were significantly lower at Lions Bay, Port Mellon and Darrel Bay (> 60% reduction compared to the reference site). A 16% reduction in germination rate was also noted for Britannia Beach. Germination tube length were only found to be significantly reduced at Lions Bay (~20 % decrease), Darrell Bay (~37% decrease) and Britannia Beach (~10% decrease). Finally, in an intertidal community assessment using species richness as an index, Chaster Bay contributed 39.94% to the total species richness, a range of 17.78% - 19.02% for moderate exposure sites and 4.50% - 12.79% for the high exposure sites.