Home Biologist Only 73 southern resident killer whales exist in the wild. Scientists...

Only 73 southern resident killer whales exist in the wild. Scientists have just discovered that 3 of them are pregnant. |

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During a routine research trip, two marine biologists were struck by what they saw in the waters of the Pacific Northwest: three endangered orcas with bulges indicating they are pregnant.

The find was delightful – there are only 73 Southern Resident Killer Whales in the wild, and time is running out to save the species from extinction. Orcas, also called killer whales, give birth to one baby at a time, every three to ten years.

“Killer whales breed very slowly, so it’s difficult to recover the population,” said John Durban, who made the discovery with his wife and research partner Holly Fearnbach. “Deaths exceed births. “

All three pregnancies appear to be at an advanced stage, they said.

“Their shape change was really big, so it was pretty obvious,” said Durban, 45, senior scientist at Southhall Environmental Associates Inc. “When they’re pregnant they have a bulge under their rib cage just like the people.”

Pregnancies are notable as the total Southern Resident Killer Whale population is at its lowest level since the 1970s. Only 44 orcas have been born since 1998, and during the same period, 81 have died or gone missing. One caught the world’s attention in 2018 when she gave birth and then carried her dead calf for 17 days and over 1,000 miles.

When Durban and Fearnbach made the discovery on September 6, they were in the middle of the Salish Sea – between Washington state, where they live, and British Columbia – on a bright orange 24-foot research boat. long. Southern Resident Killer Whales, one of the many populations of killer whales that live along the west coast of the United States and Canada and the only one designated as endangered under the Endangered Species Act disappearing, spend much of their time in these waters.

For the past 14 years, Durban and Fearnbach have used aerial drone technology to closely monitor the population of killer whales residing in the south. Although they collect data as a duo year round, they photograph killer whales each September, when marine mammals spend the most time looking for salmon in the area.

On average, orcas have a gestation period of 17 months, although there is no clear timeline for how far apart the three presumably gravid whales are.

The Southern Resident Killer Whale population consists of three distinct social groups: J, K, and L. These are social groups of whales that share a maternal ancestor. For tracking purposes, each animal is identified by a letter and pod number. The three speakers are part of the J Pod: J36, J37 and J19.

The prospect of a small baby boom is critical, say scientists, as it could help bring the species back to the brink of extinction.

“This is positive news for sure. We need births to start overtaking deaths, ”Durban said. “You can’t recover without calves, so it’s really exciting.

Still, he and Fearnbach remain cautiously optimistic, given that killer whales have a high rate of miscarriages and infant mortality.

“Unfortunately, most pregnancies don’t succeed,” said Fearnbach, 45, director of marine mammal research at the nonprofit SR³ SeaLife Response, Rehabilitation and Research.

Over the past year, several pregnancies have failed, and over the past decade there has been a relatively high rate of reproductive failure among Southern Resident Killer Whales.

The species has been listed as Endangered under the Endangered Species Act since 2005, and according to the Washington Department of Fish and Wildlife, the population continues to face three central challenges that threaten its chances of survival. long term: food shortages, chemical pollution, and noise and disturbance from ships.

Female whales are particularly affected by boaters, as they tend to stop looking for food whenever a vessel approaches. Scientists are even more concerned about the problem, as it could have dire consequences for all three pregnant – and hopefully nursing soon – mothers who will have to seek additional food to support their calves.

Dawn Noren, a biologist with the National Oceanic and Atmospheric Administration, explained that female killer whales need 25% more food during pregnancy and almost double after birth. “Very early in the lactation period, these females will need a lot more food,” she said. “Its very important.”

In light of the pregnancy announcement, authorities are urging boaters to strictly follow Be Whale Wise regulations, which state that all humans and vessels must stay at least 100 meters from marine mammals.

“We have a lot of people looking at the science to understand where we can continue to improve the odds for this population,” Kelly Susewind, director of the Washington Department of Fish and Wildlife, said in a press release. “Now that we have learned about multiple pregnancies among southerners and the impact that boats can have on new mothers, we really need everyone to follow Be Whale Wise regulations to support the survival of these whales in Endangered.”

The federal government passed a plan on September 15 to restrict commercial and recreational salmon fishing along the west coast whenever the chinook salmon population becomes particularly low, as southern resident killer whales depend on fish as their primary source. of food.

The new restrictions include reducing fishing quotas in some areas, postponing the start of commercial sea trolling for hundreds of kilometers between Cape Falcon in Oregon and Monterey Bay in California, and the closure of other areas fishing for most of the year.

“These are really important steps in helping these women have successful pregnancies,” Noren said.

Like other scientists, she too is cautiously optimistic about the outcome of pregnancies. “They have a long way to go,” Noren said. “I’ll be really excited when I see a live calf swimming next to mom.”

She is more hopeful than in previous cases, she said, as the three pregnant whales are not first-time mothers, leading to a higher risk of complications. “We expect to see some success,” Durban said. “It’s a small, endangered population, so every calf counts. “


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