Rare orca ‘superpod’ forms as search continues for J50, endangered whale many fear dead

As a frantic search was underway on Thursday for J50, a critically ill orca that is missing and feared dead, her family was engaged in a rare gathering.

The J-pod, along with the other two groupings of endangered southern resident killer whales, K and L pods, had converged near Race Rocks south of Victoria, forming what’s known as a “superpod.”

The whales performed enthusiastic greetings, jumping and splashing as they clustered together.

The convergences are reasonably rare, and at least some conservationists believe the gathering was a mourning ceremony for J50.

WATCH: Orca ‘superpod’ forms near Victoria on Thursday

“The fact that this gathering occurred and J50 wasn’t there means to us she is gone and her family is trying to deal with it,” said Robb Krehbiel with Defenders of Wildlife.

Shortly after the gathering, one key conservation group that tracks the southern residents, the Centre for Whale Research, concurred — declaring J50 dead.

Government officials aren’t so sure.

While the three-and-a-half-year-old hasn’t been conclusively seen since Friday, officials with Canada’s Department of Fisheries and Oceans (DFO) weren’t ready to concede she had passed away, and were back on the water on Friday.

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“Search efforts will continue over the weekend,” said the agency in a written update.

WATCH: Research group says endangered orca J50 is dead

0:44 Research group says endangered orca J50 is dead

“Emergency rescue plans remain in place in case she is found alive and requires medical attention.”

However, officials weren’t denying the situation appears grim.

“It is very rare to see J16, her mom, without J50 so the probability she is alive is very low, but we are out here looking for her,” said DFO marine mammal co-ordinator Paul Cottrell.

“We are covering a vast area, especially the Fraser River estuary to make sure if J50 is here, we will find her.”

The U.S. National Oceanic and Atmospheric Administration (NOAA) has similarly resisted coming to a conclusion J50 is dead.

On Friday, it said an extensive air and water search remained underway, assisted by the U.S. Coast Guard and Washington Department of Fish and Wildlife.

J50, also known as Scarlet, was born along with the last crop of successful southern resident orca births — part of an orca baby boom back in 2015.

Since then, a number of calves have been born, but none has made it to maturity.

WATCH: Officials consider plan to capture sick J50 orca for treatment

1:51 Officials consider plan to capture sick J50 orca for treatment

J50 appeared healthy and energetic at first, raising hopes among scientists and conservationists she could play a key role in helping repopulate the endangered population, which has dwindled to just 74 animals, should her death be confirmed.

However, troubling signs manifested while she was still young, according to Cottrell.

“The growth rate not comparable with other animals of that age, so she has had issues from the start,” he said.

In recent months, that concern escalated. By the end of July, J50 was severely emaciated, lethargic and eating little.

That kicked off a cross-border effort to try and diagnose and treat her, an operation that involved taking breath and fecal samples and administering de-worming and antibiotic shots.

WATCH: Condition of ailing orca ‘J50’ not improving: scientists

0:35 Condition of ailing orca ‘J50’ not improving: scientists

Now, with the real possibility that she is dead, scientists hope they can at least recover her carcass so that a necropsy can be performed to try and understand what went wrong.

There are several possible factors. A sharp decline in the southern residents’ primary food source, spring salmon, is regularly cited as a threat by the Centre for Whale Research.

Marine pollution and growing numbers of noisy vessels, which interfere with the echolocation — or  “sonar” — the orcas use to communicate and hunt are also possibilities.

In the meantime, the search continues, and DFO officials are urging anyone who spots J50 to contact the Marine Mammal Incident Reporting Hotline at 1-800-465-4336.