Monday, April 15, 2024
HomemammalsWhales, dolphins in US waters facing habitat loss, food scarcity due to...

Whales, dolphins in US waters facing habitat loss, food scarcity due to warming waters, study finds

Whales, dolphins and seals living in U.S. waters face major threats from warming ocean temperatures, rising sea levels and decreasing sea ice volumes associated with climate change, according to a first-of-its-kind assessment.

Researchers with the National Oceanic and Atmospheric Administration examined more than 100 stocks of American marine mammal species and found more than 70% of those stocks are vulnerable to threats, such as loss of habitat and food, due to the consequences of warming waters. The impacts also include loss of dissolved oxygen and changes to ocean chemistry.

The scientists found large whales such as humpbacks and North Atlantic right whales were among the most vulnerable to climate change, and that other toothed whales and dolphins were also at high risk.

The study, published last month in the journal PLOS ONE, is evidence that the way the U.S. manages whales and dolphins needs to adapt in the era of climate change, advocates for marine mammals said.

 

Climate change also could affect the distribution and behavior of marine mammals, the study states.

Whales such as the right whale, which travels north every year from the waters off Georgia and Florida, migrate hundreds of miles annually to breed and feed. Many also migrate across international boundaries, which could require new kinds of cooperation between countries. That is true of seals with large populations in the U.S. and Canada, such as the gray seal, the study says.

The federal government has tried numerous methods in recent years to try to protect declining whale species, including implementing new restrictions on commercial fishing and new vessel speed restrictions. Whales are vulnerable to entanglement in fishing gear and collisions with large ships, and scientists have said both threats are made more severe by warming waters because ocean changes cause whales to move outside of protected zones.

Safeguarding whales during the era of climate change will require ocean managers to plan for a future in which whale habitats are potentially less suitable due to the warming waters, said Gib Brogan, campaign manager with environmental group Oceana.

“This study provides guidance on how managers could prioritize species that are most vulnerable to climate effects and give these species the attention that they need,” Brogan said. “If we are going to preserve biodiversity, including marine mammals, ocean managers need to explicitly account for current and future changes in the ocean as they consider ways to conserve marine life.”

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