Humpback whales are found in all oceans and survive mostly on a diet of small crustaceans — called krill — and small fish. New research has shown that increasing temperatures could pose a threat to their diet by reducing the number of krill, which would impact migration and survival.
What's happening?
Humpback whales are often observed close to the shore and can be seen breaching and slapping the water's surface with their tails, delighting whale watchers. These majestic giants are also one of nature's great travelers, with some swimming up to 5,000 miles between their summer feeding grounds and winter breeding areas.
A new study has shown that increasing temperatures could threaten this migration pattern by impacting the diets of these whales. A study by Griffith University, as reported in SciTechDaily, examined the diet of humpback whales from different populations and found that they all heavily rely on Antarctic krill to survive.
The researchers took skin and fat samples from the whales and collected krill from the feeding grounds. They then used these to measure stable isotopes, which are atoms that can enable scientists to trace the flow of water and nutrients through plants, animals, and ecosystems.
Why is this important?
Krill provides a diet rich in fat, which is essential for the whales' migratory lifestyle. Increasing temperatures could cause krill stocks to shrink in the whales' typical feeding grounds, which means they may need to look elsewhere for food and change their diet.
Altering feeding grounds and prey could also impact the timing of whale migration and increase competition for food between individual whales. According to SciTechDaily, Jasmine Groẞ, the lead researcher on the study, said, "The migratory lifestyle of humpback whales requires predictable ecosystem productivity."
Dwindling food resources pose another challenge for these whales. Recently, the number of whales struck by boats has increased, and there have been reports of whales becoming entangled in fishing nets.
What's being done about increasing ocean temperatures?
Protecting the oceans and returning damaged habitats to their natural states can help improve the resilience of these habitats. Several groups are working to restore coastal and ocean habitats, and marine protected areas have been introduced worldwide, which can include strict regulations on when people can fish and the type of fishing gear they can use.
Additionally, nearly 200 countries in the United Nations have agreed to protect the oceans and their biodiversity by signing a binding commitment known as the "High Seas Treaty." This treaty could help conserve habitats in international waters, which could go a long way toward protecting the oceans and the flora and fauna that live there.
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