Trois-Rivires fishing festival cancelled after abrupt death of 1000s of rainbow trout

Fish biologist Pierre Magnan says a lack of oxygen likely caused more than half the trout introduced to a pond last Friday to die suddenly forcing the municipality to cancel its participation in the annual fishing festival.

Thefestival is a chance forfamilies to grab their rods and reels and fish for three days without a permit in selected places across Quebec. Last year, the 18th annual event attracted 79,000 participants.

However, this year festivities in Trois-Rivires were brought to an unexpected halt.

Festival organizers filled a pond in Pie-XIIPark with 2,000 rainbow trout on Friday, inviting would-be anglers especially those between nineand 12 years of ageto fish them for free that day and over the weekend.

However, within an hour, nearly all of the trout were afloat belly-up, dead.

Fish might have suffocated

The fish "did not survive their new environment," the City of Trois-Rivires said in a news release issued late in the day, Friday.All the weekend's events had to becancelled.

Magnanhypothesized thatthe trout died from a lack of oxygen.

"It's very important to look at the relationship between the water temperature and the concentration of oxygen," said Magnan, a professor of biology at the Universitdu Qubec Trois-Rivires(UQATR).

"You can think there is a lot of oxygen, but if the temperature is too high, the fish aren't able to absorb it."

Such mass die-offs are rare, Magnansaid, because Quebecers have long mastered the science of stocking fish ponds.

The City of Trois-Rivires is still studying what happened.