Bug study helps monitor water quality

Small bugs can tell us a lot about shoreline ecology and the health of the lake.

A recent study by the Lake Huron Centre for Coastal Conservation in shallow waters along the lakeshore is shining light on what lives in the lakebed sediments.

The six-month study was conducted by Jessica Frigault, LHCCC Science Intern, who analyzed 12,306 bugs (called macro-invertebrates), that she collected along the Lake Huron shoreline from August to October 2013.

Her project was the first-ever of this extent, providing valuable baseline information about what’s happening in the lake.

Bugs can be ‘canaries in the coal mine’, warning about deteriorating water quality because they don’t move quickly and usually can’t tolerate pollution.

They’re also a big part of the diet of fish and birds.

The study took place at 10 different Bruce County locations from Kincardine to Oliphant, chosen according to beach type: coastal wetland, sand beach and cobble beach.

“We hoped to capture how, and if, the animals changed across the beach types,” said Frigault.

The Centre also wanted know if major changes occurred during different seasons.

The study found each type of beach provides different kinds of habitat, and different animals can be found in each beach type.

While most bugs found are common in all areas, the study found that midges, scuds and mayflies were most abundant only at rocky sites.

At a site in Oliphant, snails and ‘no-see-ums’ had the greatest numbers.

Sand beaches had very different bug populations compared with cobble beaches or wetlands, showing low diversity and low numbers.

Sand beaches constantly change with weather and waves and there are no plants in the water to provide food, shelter, or egg laying sites.

Cobble beaches and coastal wetlands were similar in the types and amounts of bugs found, with the main differences depending on the season.

Mayflies, caddisflies and stoneflies were least abundant in August but prolific in late September and October.

That’s likely because these bugs mate in late May/early June, with young developing late in the season.

“While we can’t make any conclusion about the water quality of the lake with this report, the work provides us with a reference point to compare future work with what was present in 2013, and whether there are any major changes to animal populations because of water impairment or other factors,” Frigault said.

The study should also help to support efforts to conserve beaches and nearshore areas from disturbances that would affect these animals as an important food source for fish and birds.

Frigault presented her findings at the International Association of Great Lakes Researchers conference held in May at McMaster University.

Her study was possible through funding provided by Environment Canada’s Science Horizons Program, which provides valuable experience for young scientists.

In-kind support was provided by Saugeen Valley Conservation Authority and the Ontario Ministry of the Environment.

Jessica Frigault’s report is available on the Coastal Centre’s website atwww.lakehuron.ca.