Bioassessment of the Little Campbell River

An Epeorus species

The Little Campbell River (LCR) is an important urban salmon river, noted for its five species of salmon. A Rocha Canada is partnering with many stewardship groups in seeking to improve these salmon stocks, particularly the threatened Coho Salmon Oncorhynchus kisutch. The watershed covers approximately 75 km2, beginning in the Township of Langley, flowing through the City of Surrey and the Semiahmoo Aboriginal lands at its mouth where it empties into Semiahmoo Bay, just south of Vancouver near the Canada-US border. Land use in the watershed is diverse, ranging from agricultural at the headwaters, to densely urban at the mouth. A Rocha Canada has been helping to improve the river for salmon by creating spawning sites, removing invasive plants, and growing native trees at appropriate places along its course.

In 2004 and 2006 A Rocha Canada staff and volunteers performed river bioassessments by sampling for bottom-dwelling (benthic) invertebrates, using standardised sampling and analysis protocol. Habitat data were also recorded, including riparian vegetation cover and types, pH, air and water temperature, slope, water velocity (average and maximum) and stream habitat type (pool, run, riffle or rapid). Dissolved oxygen, an important parameter of aquatic systems, was measured in 2006.

Invertebrate sampling took place on 14 September 2004 and 15 September 2006. Samples were taken from three sites in 2004 and four sites in 2006 following Canadian Aquatic Biomonitoring Network (CABIN) protocol: three minute continuous sampling using a 400 micro-metres mesh kick net. Invertebrates were identified by A Rocha Canada staff and volunteers, and further identified to family or genus by Environment Canada. Results were entered into the CABIN online database (http://cabin.cciw.ca/Main/cabin_online_resources.asp) and statistical analysis was completed using the CABIN online analytical tools:

Benthic Assessment of Sediment (BEAST) assessed the stress level of each site in each year;
River Invertebrate Prediction and Assessment Classification System (RIVPACS) compared the probability of finding each taxon with the number of individuals of that taxon found at each site for each year;
the calculation of a number of additional metrics, including Ephemeroptera Plecoptera-Trichoptera (EPT) richness (which measures the number of pollution sensitive mayflies, stoneflies and caddisflies), percent dominant taxa, and total abundance.

Benthic sampling on the Little Campbell River

The bioassessments of sampling sites in the LCR and Fergus Creek showed that areas of the LCR watershed are experiencing varying degrees of human-induced stress, for example as shown by low numbers of EPT taxa. All of the sites sampled in 2006 had dissolved oxygen levels much lower than the mean of the reference group with which they were being compared, which may partly explain the stressed or potentially stressed invertebrate communities observed at some of these sites.

Ongoing bioassessments in the Little Campbell River and its tributaries by government agencies and stewardship groups such as A Rocha are helping to identify sources of pollution, assisting in public education about water quality issues and attempting to resolve existing problems. Bioassessment will be used in future years to test the aquatic habitat quality and thereby measure the effectiveness of habitat improvements and public awareness programmes within the watershed.

Project leader: Rachel Joy Krause, Science Horizon Intern

Partners: Environment Canada, BC Environment, Little Campbell Watershed Society