Natural Resources Minister Bruce Northrup said Donald Dube's death in Saint-Leonard, N.B., last October cast a light on the problem of illegal deer farms, even though a former government biologist said they have existed for years.
"As far as past governments, I don't know why they overlooked it," Northrup said Thursday.
Police said Dube died after the dominant buck in the herd attacked him with its antlers and hoofs.
Northrup said department staff have since identified 15 farms with more than 140 white-tailed deer.
But Gerry Redmond, who used to work for Natural Resources as a biologist, said he raised concerns about illegal deer farms in the 1980s and 1990s but the issue never became a priority.
"It wasn't addressed until this problem arose," Redmond said.
"In retrospect, it should have been, and perhaps that gentleman would still be alive today."
Redmond said he doesn't think the department knew whether the animals were being imported from other provinces or taken from the wild, nor what the farms were doing with the deer.
Biologists warn captive white-tailed deer pose a risk to native wildlife, human health and public safety because of disease.
Northrup said owners of each farm have been told they can kill the deer for personal use, but none of the meat can be sold, traded or exported.
They can also move the deer to another province where white-tailed deer can be legally kept in captivity, such as neighbouring Quebec, but only with the approval of the Canadian Food Inspection Agency.
The owners have until June 15 to comply. Northrup said if they don't, the department could take them to court.
He said his staff will monitor the deer farms to ensure none of the animals are released into the wild.
Permits are available in New Brunswick to keep some non-native deer species such as elk, fallow deer and red deer in captivity for agricultural purposes.