The wee fishies did not die in vain.

The venerable Cochrane's Dairy Ltd. and dairy official Barry Cochrane were convicted Wednesday under the federal Fisheries Act of dumping toxic substances into the Castor River southeast of Ottawa in 2012.

Those substances -- milk and cleaning solutions -- were indeed "deleterious substances" as defined by the Act, Judge Catherine Kehoe found.

And they found their way into what the Act poetically terms "water frequented by fish."

In the room frequented by lawyers, Kehoe recapped the grim results of scientific tests performed on samples seized by Environment Canada investigators.

The tests involved throwing a bunch of unfortunate trout into fishtanks full of the seized samples; scientists counted the survivors the next day.

At high concentrations, the court heard there were no survivors, making the samples "acutely lethal."

"There is no question that it was toxic," said Kehoe.

The lab trout, however, were the only confirmed fish fatalities stemming from the dairy's transgressions.

The dairy had at first pleaded ignorance when investigators alerted them to effluent pouring from a concrete pipe near the river in August 2012.

They vowed to shape up, but ultimately began draining their tanks into a field by the river, which did not impress investigators during a November visit.

Kehoe agreed with Crown prosecutor Emilie Taman the dairy ought to have done a "full inspection" of their wastewater system as soon as they were alerted to the problem in June.

Sentencing submissions begin June 19.

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