Another endangered killer whale is losing weight, but several believed to be pregnant

Less than a month after the death of a southern resident killer whale known as J50, scientists are raising alarm bells about another sick whale.

Good news and bad news for B.C.'s struggling southern resident population

K25 has been tracked using aerial photographs since 2008. Scientists say the whale looks significantly thinner than in previous years. (NOAA)

Less than a month after an ailing southern resident killer whale known as J50 died, scientists are raising alarm bells about another sick member of the West Coast orca population.

According to a release from the National Oceanic and Atmospheric Administration, a 27-year-old male whale known as K25 looks to be in "notably poorer body condition compared to recent years," judging from aerial photographs.

"This year, his body profile is thinner than previous years," the release reads in part.

Southern resident killer whales inhabit a range between southeast Alaska and central California, but are commonly seen off southern Vancouver Island and northern Washington state during the summer.

While the reasons for J50's emaciation were never determined, scientists have a theory about why K25 may look thin.

"This change coincides with the loss of his mother, K13, in 2017, and likely reflects the challenges he faces without her help in capturing and sharing prey," said the release.

Male killer whales tend to rely on help from their mothers and other family members to meet their increased energy demands, and are often vulnerable following their mother's death.

While J50 was just three years old. K25 is much older — just three years short of the typical 30-year-old lifespan of a male killer whale.

Multiple whales pregnant

But there's also good news for the whale population that experienced tragedy after tragedy over the summer.

NOAA said aerial images indicate whales in all three pods — J, K, and L — are pregnant, including K25's sister, K27.

"This is vital news for this critically endangered population," said Scott Rumsey of the NOAA.

"We ask that vessels minimize disturbance of these pregnant whales, in addition to K25, to maximize the chances of successful pregnancies." 

The population has a high rate of unsuccessful pregnancies. Over the past 10 years, only three whales have been born.

With the death of J50 in August, only 74 southern resident killer whales remain.

The southern residents rely on their favoured food: chinook salmon.

While they look like other killer whales on the West Coast, they breed and feed among themselves, travelling in tight family groups.

The whales are threatened due to high levels of vessel noise and toxic contamination levels, and low supplies of prey.

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