What is CSI?
Coastal Scene Investigation (CSI) is a long term program to monitor intertidal species diversity of mid to low rocky intertidal beaches along the protected coast of British Columbia, Canada, as a method of determining the effects of pollution on the species that live there. This initiative was called Project Save our Shores (SOS) from 1985 to 1993. Studies were done from 1990-1993 (Bard, 1998) and in 2004 (Bard et. al., 2005) to evaluate the intertidal species diversity along pulp mill pollution gradients in British Columbia, Canada. Since the original study, pollution abatement programmes for the pulp mills have resulted in improved effluent quality with lower levels of biochemical oxygen demand (BOD), total suspended solids (TSS) and absorbable organic halides (AOX). Monitoring was completed in three regions: Howe Sound, Powell River and Prince Rupert. Crofton, on Vancouver Island, is a fourth region that was studied only in 1990, '91 and '93. Therefore, no comparison over time was done. Each region has one or more pulp mills and sites that were investigated were at increasing distances from the mills in each region. From previous studies at these >30 sites, we have determined that there are at least 27 broad taxonomic groups (e.g. sea anemones, crabs, fish, algae, etc.) and over 250 species represented as egg cases, juveniles or adults in this habitat.
In each of the three regions, intertidal species richness (number of species found) increased significantly as distances away from the pulp mill increased. It was also found that in each region over the past decade, overall mean species richness has increased. These increases in species richness over time are coincident with decreases in pollutants, including biochemical oxygen demand (BOD), total suspended solids (TSS) and absorbable organic halide (AOX) levels in pulp mill effluent. These decreases in pollutants stem from legislation in the late 1980's requiring pulp mills to clean up their operations. However, coincidence in trends does not necessarily reflect a cause and effect relationship between effluent toxicity and species diversity. Cause and effect relationships are extremely difficult to establish in ecological field studies. This is especially true in this instance because of the lack of ecological baseline data from before pulp mills were in operation. Despite this limitation, our results do suggest that intertidal habitat and species diversity are improving.
The goal of these studies is to determine and monitor the effects of pulp mill effluents on intertidal community structure. Species studied in surveys were found to have highly varying tolerances to exposure to mill effluent. CSI allows for an inexpensive means of determining the level of exposure of a site to mill effluent through the survey of intertidal species richness. The intertidal zone is often considered the nursing area for the subtidal; many juvenile species are found here as well as sensitive species. The species richness is therefore an indicator of overall ecosystem health and pollution effects. CSI is a sensitive environmental assessment tool to identify sites which have not recovered despite decreased effluent toxicity. It can also be used to identify sites with high species richness and candidates for marine protected areas.