Water tests have confirmed the presence of a pesticide in a western Manitoba lake and while officials say swimming in the lake is still safe, eating fish from it isn't advised.

Campers raised the alarm at Seech Lake, north of Oakburn, Man. — approximately 250 kilometres northwest of Winnipeg — about two weeks ago after finding dead water beetles and crayfish on the shore.

Manitoba Sustainable Development and Health Canada both collected water samples and launched investigations as a result.

On Friday, a provincial spokesperson confirmed a pesticide, sold under the brand name Matador, was found in the lake in low levels. The levels detected were below what would be considered a health concern.

"Testing of Seech Lake indicates that lake users can resume use of the lake water for domestic uses and swimming," a provincial spokesperson said on Friday of the investigation's status.

CBC News requested additional information from Health Canada. The agency wasn't able to provide any information by Friday evening.

Denise Melnyk, who was camping at the lake with her family, said an aerial crop sprayer was spraying crops near the lake not long before the dead bugs were discovered.

While the water was determined to be safe for swimming, the province said the possible effects on fish are still being assessed.

"As a precaution, it is recommended that people continue to avoid eating fish from this lake until further notice," the province said.

Matador, manufactured by Syngenta, is an insecticide typically used on crops including canola, spring wheat, durum, winter wheat, barley and oats, according to the company's website.