Canada’s DFO Concerned About Whales’ Learned Depredation Behavior

A humpback whale. File photo by Ed Lyman/NOAA.

Canadian fisheries officials, expressing concern about whales snatching fish from fishing gear, are urging commercial fishermen to avoid inadvertently encouraging such behavior.

Fisheries and Oceans Canada said in a statement issued in mid-June that depredation (the act of plundering) by killer and sperm whales has been reported in the groundfish longline fishery in British Columbia, and that there have been increased reports this year of depredation by killer whales on groundfish longline fisheries in Washington state waters, yet no current increase of reporting in BC waters.

Depredation is learned behavior that can spread throughout whale social groups and once established is impossible to eliminate, Fisheries and Oceans officials say, adding that as whale populations transverse boundaries between the United States and Canada, it is important to monitor these events.

Fisheries and Oceans Canada is urging harvesters to prevent this behavior from spreading by not feeding whales directly or indirectly and not haul gear in the vicinity of killer and sperm whales. The federal agency also recommended that harvesters advise other fishermen if they encounter depredation.

In addition, Fisheries and Oceans also recommends reading depredation information available at the BC Cetacean Sightings Network website,

Incidents of predation can be reported by emailing or by calling (800) 465-4336.