- Biden opens home to 'Quad' leaders for farewell summit
- Sally Rooney returns with 30-something questions
- Wallabies sense 'massive' chance to upset All Blacks
- Taiwan questions two in probe into Hezbollah pagers
- Viral Korean Olympic shooter scores first acting role as assassin
- Farrell set for 'challenge' of downing Bordeaux in Top 14
- Springbok Etzebeth diverts attention from looming caps record
- Inter on a high ahead of Milan derby as Napoli face Juve test
- Bank of Japan leaves key interest rate unchanged
- Asian markets track Wall Street record to extend global rally
- Guirassy and Anton to return to Stuttgart with new side Dortmund
- Marseille bidding to continue 'almost perfect' Ligue 1 start
- Arnold quits as coach of Australia men's football team
- Harris and Oprah hold star-studded US election rally
- Allies to remember failed WWII parachute operation
- Perez leading new-look Villarreal charge against leaders Barca
- Man City face Arsenal in Premier League title showdown, Postecoglou under pressure
- Fake celebrity endorsements, snubs plague US presidential race
- Documentary brings Argentine 'death flights' to the big screen
- Strike shows challenge to Boeing 'reset' of labor relations
- World leaders to gather at UN as crises grow and conflicts rage
- How plastic pollution poses challenge for Canada marine conservation
- Scientists track plastic waste in pristine Canada marine park
- South Africa's Buhai grabs LPGA Queen City lead
- Japan inflation firms to 2.8% ahead of BoJ rate decision
- Russia's Kadyrov accuses Musk of 'remotely disabling' his Cybertruck
- Titan sub had to abort a dive days before fatal implosion: testimony
- Ohtani eyes MLB history after surpassing 50 stolen bases
- Barca downed by Monaco as Arsenal held in Champions League stalemate
- Head's 'good night at office' after century seals win over England
- Dubois seeks legitimacy with Joshua scalp
- Rate cut could lift consumer spirits before US elections
- Last-gasp Gimenez strike sends Atletico past Leipzig
- Barca stumble at Monaco after early red card
- Raya heroics save Arsenal in Champions League opener at Atalanta
- Guardians beat Twins to secure MLB playoff berth
- Jihadist attack in Mali capital killed more than 70: security sources
- Alonso hails 'efficient' Leverkusen after Feyenoord rout
- Ex-Man United striker Anthony Martial joins AEK Athens
- NFL unbeatens meet as Texans visit Vikings, Steelers host Chargers
- Head's hundred seals Australia win over England in 1st ODI after Labuschagne strikes
- Dream debut for Wirtz as Leverkusen thump dire Feyenoord
- Myanmar flood death toll climbs to 293: state media
- Israel army says West Bank air strike kills 4 militants
- LIV golfers get green light for US Ryder Cup team, PGA Championship
- US accuses social media giants of 'vast surveillance'
- Ten Hag to bed Hojlund, Mount in carefully when they return for Man Utd
- Breaking bad as McIlroy endures 'weird' day
- EU chief announces $11 bn for nations hit by 'heartbreaking' floods
- Spanish PM, Palestinian leader urge Mideast de-escalation
Heatwaves may be driving whale decline in Pacific: study
The number of North Pacific humpback whales plummeted 20 percent in less than a decade, and marine heatwaves may be the main culprit, according to a study released Wednesday that spells a troubled future for the majestic sea mammals.
Thanks to conservation efforts and the end of commercial whaling in 1976, the region's humpback population steadily increased until 2012.
But over the last decade, whale numbers have declined sharply, researchers reported in the journal Royal Society Open Science.
A team of 75 scientists compiled the largest photo-identification dataset ever created for a large marine mammal to track North Pacific humpback populations from 2002 to 2021.
Using images of the whale's unique tails the team was able to log some 200,000 sightings of more than 33,000 individuals.
Up to 2012 the humpback population steadily increased, and it was widely assumed it would eventually level off at their natural "carrying capacity" -- the number of whales the ocean can support.
Instead, they saw a steep population decline.
From 2012 to 2021 the number of humpbacks fell 20 percent from some 33,000 individuals to just over 26,600.
For a subset of whales that wintered in Hawaii, the drop was even more pronounced: 34 percent.
That turned out to be a highly significant difference.
From 2014 through 2016 the strongest and longest marine heatwave ever recorded ravaged the Pacific northeast with temperate anomalies sometimes exceeding three to six degrees Celsius, altering the marine ecosystem and the availability of humpback prey.
"My jaw was on the floor," study author Ted Cheeseman, whale biologist and a PhD student at Southern Cross University in New South Wales, told AFP. "This is a much bigger signal than we expected."
"Our estimation is that about 7,000 whales mostly starved to death," he said.
It is normal even in healthy populations for numbers to fluctuate, but such an abrupt decline for a long-lived species points to a major disruption in the oceans.
- 'The ceiling crashed' -
In this case, the scientists speculate, the extreme marine heat actually reduced the carrying capacity threshold for humpbacks.
"Instead of the whales coming up to the ceiling, the ceiling crashed down on the whales," Cheeseman said.
The fact that humpbacks were unable to shift their already flexible diet is a telltale indicator for overall ocean health.
"It's not just the whales' food that declined," Cheeseman added, noting drops in the populations of tufted puffins, sea lions, and seals. "A warmer ocean produces less food."
Some commercial fisheries also felt the impact.
According to the Intergovernmental Panel on Climate Change, marine heatwaves -- already more frequent and intense -- are projected to increase globally over the course of this century.
- Still a success story -
For hundreds of years, whalers from across the planet hunted humpback whales for their oil, meat and baleen, their feeding filtration system.
By 1986, the IUCN had listed the species as globally endangered.
Humpback whales continue to face threats today, primarily from ship strikes and entanglements in fishing nets.
But international restrictions on commercial whaling allowed the global humpback whale population to rebound to more than 80,000 mature individuals.
But today conservation goes hand-in-hand with climate action.
"It is a great success story that these whales are no longer in immediate danger of extinction like they were 50 years ago," Cheeseman said.
"And yet, there's a new reality of changing oceans that we have to live with."
C.Amaral--PC