OTTAWA -- Animal suffering won't be considered when a Health Canada agency next reviews licences for poisons used to kill predators, the department has ruled.

In a decision released this week, Health Canada says the Pest Management Regulatory Agency won't include “humaneness” in how it assesses toxins such as strychnine.

“Health Canada will not be taking steps towards incorporating humaneness considerations into the pesticide risk assessment framework,” said the department's ruling.

“There are currently no internationally recognized science-based parameters to evaluate the humaneness of pesticides.”

Sara Dubois, a wildlife biologist with the British Columbia SPCA, said that's not true. University labs have extensive animal welfare protocols and Australia and New Zealand have also moved toward such criteria.

“An absence of information doesn't mean that pain and suffering doesn't happen,” she said. “That's the frustrating part.”

The decision on strychnine, compound 1080 and cyanide came after more than two years of public consultations sparked by a letter signed by 50 scientists and animal-welfare advocates from across Canada and three countries.

More than 4,000 letters were received, most form letters from letter-writing campaigns. Non-governmental organizations participated as did provinces and municipalities.

“Canadian public respondents are concerned about the humaneness of the three predacides currently registered for use in Canada,” the decision says. “Many of these same respondents feel the predacides should be banned in favour of alternative predator control measures.”

Animal science researchers have called strychnine a particularly painful and cruel way to die.

Within 20 minutes of being dosed, muscles start to convulse. The convulsions increase in intensity and frequency until the backbone arches and the animal asphyxiates or dies of exhaustion.

Groups such as livestock associations said predator poisons are already tightly controlled. Environmental and veterinary groups called for humaneness parameters in the assessment of pesticides.

Provincial governments said the issue was in their jurisdiction.

One of the biggest users of strychnine in Canada is the Alberta government. Alberta uses it to poison wolves in an attempt to protect caribou, which have been made vulnerable by many years of heavy industrial use of their habitat.

The province has poisoned hundreds of wolves in its caribou program, as well as many non-target species.

Health Canada will undertake its regular review of the three poisons later this spring. A petition opposing their use has nearly 700 signatures.

Animal advocates have also requested that federal Health Minister Patty Hadju review Health Canada's last decision to renew licences for the poisons.

Strychnine is no longer used to control predators in most Commonwealth and European countries or most U.S. states.

This report by The Canadian Press was first published Feb. 2, 2021