Photo: NOAA

A southern resident killer whale's weight loss is worrying scientists.

Aerial images by the National Oceanic and Atmospheric Administration taken off the B.C. coast show J-pod orca J17 has lost a troubling amount of weight over the past three and a half years. 

U.S. scientists say the matriarch is now showing signs of “peanut head" due to blubber loss, CTV News reports.

And J17’s calf, three-and-a-half-year-old J53, is also showing declines in appearance. 

The southern residents' population has shrunk to just 75 in the waters between Victoria, Seattle and Vancouver, and Canada’s Department of Fisheries and Oceans recently brought in new measures to keep vessels at least 400 metres away from the orcas, starting June 1, to allow them to feed uninterrupted.

Vessels have also been barred from “interim sanctuary zones” off southwestern Vancouver Island, Pender and Saturna islands.

​Researchers are not intervening at this time, but the DFO has asked ships to voluntarily turn off echo sounders when not in use, to idle engines and slow down when near whales.

The department is also closing recreational and commercial salmon fishing in parts of the Strait of Juan de Fuca and the Gulf Islands.

– with files from CTV Vancouver Island