A new study offers a glimpse into the state of mind of North Atlantic right whales when they are trapped and dying in fishing gear.

By measuring hormone levels in the collected feces of the endangered whales, scientists have determined the animals' stress levels are "sky-high."

"What it tells us is that there is extreme physical trauma and extreme suffering going on," said Rosalind Rolland, a senior scientist at the Anderson Cabot Center for Ocean Life at the New England Aquarium and the lead author of the study.

"Because these hormone levels aren't just a slight elevation — they are through-the-roof elevated."

It's not a subtle thing, it's an 'Oh, my God, this animal is really, really, in trouble.' - Rosalind Rolland, New England Aquarium scientist

The presence of the stress hormones was measured in the feces of 125 individual North Atlantic right whales over 15 years, including six chronically entangled whales, a live stranded whale and five other whales that were killed by ship strikes.

Hormone levels, including the textbook "fight-or-flight" hormone cortisol, were recorded as being very high in animals that suffered a slow death but not in those that died suddenly from collisions with vessels.

Rolland said the study is the first of its kind to look exclusively at what North Atlantic right whales go through while tangled in fishing lines. Whales have died as a result of the entanglement.

"A lot of entanglements occur in this population," she said. "Eighty-three per cent of this population of North Atlantic right whales has been entangled in fishing gear at some point, and 50 per cent at least twice."

Rosalind Rolland, a senior scientist and veterinarian with the New England Aquarium, says stress levels of whales entangled in fishing gear are 'sky high.' (New England Aquarium)

As a veterinarian, Rolland said she wasn't qualified to speak to what similar levels of the stress hormones would be like in humans, but she was able to compare their impact on other animals.

"If I saw these types of cortisol levels in a dog or a cat or a horse, I would be completely floored and very alarmed," Rolland said. "It's not a subtle thing, it's an 'Oh, my God, this animal is really, really, in trouble.'"

The North Atlantic right whale population suffered devastating losses this year when 16 of the whales were found dead. There are only about 450 North Atlantic right whales left on the planet.

Began with pregnancy hormones

Scientists have been collecting feces samples from North Atlantic right whales since 1999.

"I got the crazy idea that you could develop a pregnancy test for right whales," Rolland said. "At that time, the calving rates in this population had just plummeted down to single digits. In fact, there was only one calf born in the year 2000."

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Rolland has published papers on the detection of pregnancy hormones, which she said eventually led her to the study of the stress hormones in entangled whales.

The process of extracting stress hormones from the whale feces is described as "pioneering" by the New England Aquarium.

Tested long-dead whales

According to Rolland, the process can be used to not only examine the stress levels of living whales but also on animals that have been dead as long as 15 years.

But the process of actually collecting whale feces was made easier by the fact the samples float on the ocean's surface, and Rolland and her colleagues were aided by tracking dogs.

This small, female whale on Miscou Island in New Brunswick died from severe entanglement this summer. (Shane Fowler/CBC)

"These are the dogs that have the same training as a narcotics dog, only that you train them on right whale poop," said Rolland. "And we trained them to work off boats in the water for four years, and they were phenomenal. We collected a lot of samples during those years."

Rolland's paper "Fecal glucocorticoids and anthropogenic injury and mortality in North Atlantic right whales Eubalaena glacialis" was published in Endangered Species Research by the Inter-Research Science Centre.