Bugs rate water quality in Stanley Park

SPES’s Conservation Technician Meghan Cooling has been busy in Stanley Park’s streams this spring searching for aquatic invertebrates. These spineless wonders help us measure water quality. Meghan conducts stream sampling twice a year, in the spring and fall, checking each of Stanley Park’s four streams twice during those periods to track their health.

Meghan Cooling, SPES Conservation Technician (right), and a volunteer net aquatic invertebrates in Beaver Creek (Photo: Jess Causby/SPES)

Jess Causby, our Communications Volunteer, accompanied Meghan on one of her sampling expeditions to find out what an aquatic bug hunt entails. Here’s what she found:

Why does SPES do the sampling?

The types and diversity of the aquatic invertebrates found provide an indication of the water quality depending on how well that invertebrate group tolerates pollution; if a large variety of pollution intolerant species are found, this indicates the water is of good quality. But, if few species are discovered, or if what’s found is mostly pollution tolerant, then this indicates poor water quality.

SPES volunteer Katelyn James examines the invertebrate collection from Ceperley Creek (Photo: Meghan Cooling/SPES).

Which invertebrates act as water quality indicators?

The most important good quality water indicators are aquatic insects in the mayfly (Ephemeroptera), stonefly (Plecoptera), and caddisfly (Trichoptera) groups, which is why this method is also called the EPT index. Alternatively, there aren’t any particular invertebrates that are always found in bad quality water; it’s more the absence of pollution-tolerant species which indicates poor water quality. But, the water boatmen (a type of True Bug) and leeches have both been found in some incredibly filthy water!

What was determined and how does the Park use this data?

(Ratings options are Good, Acceptable, Marginal, Poor)

Beaver Creek and North Creek had marginal site assessment ratings, Zoo Creek has an acceptable rating, and Ceperley Creek (the outflow of Lost Lagoon) has a poor rating.

SPES sends the stream data to The Pacific Streamkeepers Federation. Right now our surveys are aiming to collect accurate baseline data. If SPES were to notice a particular stream’s health deteriorating, some stream enhancement projects could be considered.

What can I do to help?

Keep the Park’s streams clean! Don’t litter or dump substances into pond and stream water. In your garden, reduce or eliminate the use of chemical fertilizers and pesticides.

If you are interested in volunteering with SPES’s Conservation Department, please contact Tobias Jones, Volunteer Coordinator, at vols@stanleyparkecology.ca

Thanks in part to NSERC PromoScience – Science Odyssey’s support for this work.

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