HONOLULU — Research into the decline of humpback whale sightings in Hawaii points to a food chain disruption likely caused by warmer ocean temperatures in the whales’ feeding grounds in Alaska, federal officials have said.
U.S. and international researchers, wildlife managers and federal officials were meeting in Honolulu Tuesday and Wednesday to discuss the decline in sightings of humpbacks that traditionally migrate each autumn from Alaska, where they feed during the summer months, to Hawaii, where they mate and give birth during the winter.
Data presented at the meetings shows a strong correlation between warming oceans and the missing whales, said Christine Gabriele, a federal wildlife biologist who monitors humpbacks at Glacier Bay National Park in Alaska.
Three factors have warmed the ocean in Alaska since 2014, the same year scientists noticed a decline in sightings in Hawaii.
There was a change in an ocean current known as the Pacific Decadal Oscillation, a warm El Nino period in 2016, and a massive “blob” of warm water in the region.
The whales may also be spreading out or moving north to cooler waters to find their prey, which could explain why there are fewer sightings in Hawaii.
Based on the latest large-scale population study, it is estimated that half of all North Pacific humpbacks make the journey to Hawaii each year, putting the total number of whales making the 6,000-mile round trip migration around 11,000 annually.
And while scientists agree a decline in sightings in both Alaska and Hawaii is because of a change in food, they still don’t know if there is a larger issue that could be impacting the entire habitat.
Officials with the National Oceanic and Atmospheric Administration hope this week’s meetings will help them to form a plan and get funding to help ensure the species’ continued success. NOAA conducts research, creates federal regulations and enforces laws meant to protect the whales.
“At least in Alaska, there’s something happening with the prey,” said Marc Lammers, research coordinator for NOAA’s Hawaiian Islands Humpback Whale National Marine Sanctuary. “What we didn’t really resolve is whether that applies more broadly to a larger area like across the North Pacific.”
The researchers said that while historically there have been dips in sightings on specific islands in Hawaii, those declines were usually accounted for by an increase in sighting somewhere else in the archipelago.
But over the past four years, there has been a downward trend of between 50 percent and 80 percent of sightings across the entire main Hawaiian Islands, something Gabriele called “unprecedented.”
There has also been a decline of nearly 60 percent of sightings in Alaska’s Glacier Bay.
“There is no question that the world is changing, the oceans are changing,” Lammers said. “The humpback whales are reflecting those changes and we now need to try to understand whether this is something that will eventually correct itself, and time will tell, or whether this is something that points to a more sustained change.”
Have they “eyed” the correlation of higher room taxes. rental car rates, airfares, sales taxes, and food costs in Hawaii? Yep, positive proof why the whales aren’t coming to Hawaii like they were.
But, of course, it will need further study.
Did they study the whale-killing sonar that all the militaries use??? The whales heard that military wants to conduct war games on the Kona Coast, and they didn’t want to expose their newborns to our disease.
The population of Humpback Wales have experienced massive growth roughly quadrupling since 2003. Other wale populations have also grown substantially.
Guess what? The wales need to eat, and they need to eat a lot. If the predator population grows and the bait fish population does not grow, there is eventually not enough bait fish to eat. Why is this not being looked at?