A series of drone photos illustrating the dramatic deterioration of a southern resident killer whale has marine mammal experts urging boaters in B.C. and Washington state waters to keep their distance from the creatures as the weather warms up.

J-17, also known as Prince Angeline, has been under particular scrutiny after scientists observed the 43 year-old female orca showing signs of "peanut head" in the fall.

The deformity happens when whales are malnourished and begin using their blubber stores to survive.

Three side-by-side images showing the whale going from a robust size in September 2015, dramatically thinner in September 2018 and even thinner last week.

The images were taken as part of a partnership between Canadian and American researchers using drone photogrammetry to compare health and condition in the mammals over time.

The images were taken in U.S. waters and were released by the National Oceanic and Atmospheric Administration (NOAA) to highlight the mammal’s decline.

"Seeing these new photos of J17 and the decline in her body condition really heightens the urgency and raises awareness that we really need to be doing all we can to protect these whales," said NOAA marine biologist Lynne Barre.

Her research team, with help from experts from the Vancouver Aquarium, believes a lack of the orcas’ primary food source of Chinook salmon, marine traffic sounds and high levels of contaminants in the water are combining to devastating effect in the mother of four.

"If they're using their blubber stores, those contaminant can circulate even more in their body, causing health problems," she explained.

As the boating season quickly approaches and more recreational mariners head to local waters, researchers are urging them to follow new regulations that come into effect June 1st .

Those regulations require boaters to keep more distance between their vessels and the whales.

Earlier this month, federal officials were in Vancouver to announce the protections for the 75 remaining southern resident killer whales, which double the minimum distance from 200 to 400 metres.

There are also designated protection areas closed to fishing where all mariners are asked to slow down to seven knots and stay one kilometre from the orcas.

South of the border, Washington State has enabled legislation requiring boaters and commercial vessels stay 365 metres from the mammals.

Barre notes that not only is J15 declining, but her youngest calf, J53, is also malnourished.

The youngster, also known as Kiki, isn’t quite four years old yet and is struggling to stay with J-pod along with her mother.

"We're really hoping people will educate themselves about proper boating on the water so they can let the whales forage undisturbed and hopefully J17's condition will improve."