There’s been a decline in humpback whale sightings in the Hawaii region that scientists believe is tied to the impacts of climate change.
A new report from the Associated Press says that warmer ocean temperatures in the whales’ feeding grounds in Alaska are causing disruption of their food chain.
Meetings were held this week in Hawaii to discuss the decline of the humpback sightings. In attendance were U.S. and international researchers, wildlife managers and federal officials.
The whales traditionally migrate each year from Alaska (where they feed) to Hawaii, where they mate and give birth.
There appears to be a strong connection between warming oceans and missing whales, according to data that was presented at this week’s meetings, the Associated Press reported.
As the oceans in Alaska have warmed over the past few years, scientists have noticed fewer whales in Hawaii.
Three key factors are causing the ocean temperatures to rise including a change in the ocean current known as the Pacific Decadal Oscillation, a warm El Nino period in 2016, and a massive area of warm water in the region.
The Pacific Decadal Oscillation, in particular, is a current that traditionally switches between cool and warm periods over the course of many years. In 2014, it switched to warm.
Data shows that “it was more favorable for the whales when we were in a cold period, and then less favorable when the (Pacific Decadal Oscillation) switches to warm,” said Christine Gabriele, a federal wildlife biologist who monitors humpbacks at Glacier Bay National Park in Alaska.
“In Glacier Bay, we have definitely seen a much lower calving rate and much lower calf survival as well as juvenile survival,” Gabriele added. “I think there are metabolic issues that are probably related to the production of a calf. We’re not clear if it’s a lack of pregnancy or lack of ability to carry it to term.”
The Associated Press also reported that the whales may be spreading out or moving north to cooler waters to find prey. This might explain the fact that there are now fewer sightings in Hawaii.
The most recent study estimated that about half of all North Pacific humpbacks make the journey to Hawaii each year. That’s about 11,000 whales annually.
In 2016, many humpback whales were removed from the Endangered Species list, but they remain federally protected.
Though scientists appear to agree that a change in food availability has led to the decline in the presence of the animals in Alaska and Hawaii, they remain uncertain about whether a larger issue is impacting the whale habitat.
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