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3 critically endangered B.C. killer whales are pregnant : scientists say
Date Added: September 20, 2021 07:32:05 AM
Author: Sutra Web Directory
Category: Health & Beauty: Environmental Health
 
An adult female southern resident killer whale named J36 is one of three orcas that is pregnant, according to Washington scientists Holly Fearnbach and John Durban, who used drone aerial photography to capture changes in the orcas' shape over time. (Holly Fearnbach (SeaLife Response, Rehabilitation and Research) and John Durban (Southall Environmental Associates)
 

Three critically endangered killer whales that frequent B.C.'s waters are now pregnant.

That's according to aerial drone research by scientists in Washington state, and it has researchers in B.C. hopeful that the three mothers-to-be will overcome tough odds and help bring their species back from the brink.

The three presumed pregnancies were discovered by two scientists in the U.S., Holly Fearnbach and John Durban, who collaborate often with B.C. experts, said the director of Ocean Wise's marine mammals research group.

"It's pretty exciting and it's very significant," Lance Barrett-Lennard told CBC News. "The southern resident population of which [the] J-pod belongs to is critically endangered."

"In most years they have no reproduction at all. So having three pregnancies is good, it's exciting. This is what the pod needs."

There are currently only 74 southern resident orcas left, down from more than 90 in the 1970s. The three pregnancies are in what scientists call the "J-pod," a group of southern resident killer whales. Members of the pod are named starting with the letter "J" and a number; the three mothers-to-be are J19, J36 and J37.

University of British Columbia researcher Josh McInnes, with the marine mammal research unit at UBC's Institute for the Oceans and Fisheries, said that although killer whales have a high rate of miscarriages and infant mortality, he and other researchers are "excited" and "hopeful" at least some of the three pregnancies will help rebuild the endangered species' population.

"Having three calves being born that could possibly survive ... it might just help a little," he said. "The first year is critical; killer whales have a 50-50 chance of survival especially in the first year."

'Fingers crossed that they are successful and the calves survive'

But he cautioned that neonatal mortality of killer whale calves is "quite high" alongside miscarriages, and many of the threats to orca survival continue to put them at risk. But the recently discovered pregnancies appear to be fairly advanced in their terms.

"Fingers crossed that they are successful and the calves survive," he said.

A series of miscarriages have made headlines in recent years, raising fears of the continued decline of the orcas. With such a small overall population, the risks of collapse are real.

In 2018, one female orca, J35, carried her stillborn baby for more than two weeks in the water in what experts called a "tour of grief." But two years later, she gave birth to a healthy baby.

Barrett-Lennard described the U.S. scientists behind the discovery as "colleagues and friends" who often work with him to advance aerial imagery research, using drones just 30 metres above the water's surface.

"The use of drones has revolutionized everything," he explained. "It supplies us with very high-resolution photographs.... One can see the edges of the whales pretty well and measure their total length and shape ... and of course we can detect pregnancies fairly early."

Southern resident orcas are listed as "endangered" by the Canadian and U.S. governments, as their salmon food sources dwindle and shipping traffic creates noise and often-deadly animal collisions. Southern resident killer whales are distinct from northern resident populations, as well as transient orcas.

'The decline is expected to continue'
 
In June, the federal government issued an interim order for the protection of southern resident orcas, boosting existing regulations impacting shipping traffic in B.C. waters where the species is known to travel.

"The population is small and declining, and the decline is expected to continue," the federal government states in its species profile of the orcas. "There are forecasts of continued low abundance of Chinook Salmon. Southern residents are also threatened by increasing physical and acoustical disturbance, oil spills and contaminants."

Noise pollution along busy shipping routes impedes the orcas' use of echo-location to hunt as well as their communication within their pod. 

Barrett-Lennard described the situation as "death by a thousand cuts."

The two Washington researchers involved in the study, as well as the U.S. government's National Oceanic and Atmospheric Administration, could not be reached by time of publication.

"The southern residents are iconic for us," McInnes said, "and we're really hoping that there's some survival for the new calves ahead."

~ Via CBC