Climate Change Imperils Marine Mammals in U.S. Waters, According to Comprehensive Study

A landmark assessment reveals that marine mammals such as whales, dolphins, and seals inhabiting American waters are increasingly jeopardized by the consequences of climate change, including elevated ocean temperatures, sea-level rise, and reduced sea ice volume.

The study, conducted by researchers from the National Oceanic and Atmospheric Administration (NOAA), scrutinized over 100 marine mammal stocks native to U.S. waters and discovered that more than 70% are susceptible to various threats. These include the diminution of their habitats and food sources, a result of the ocean warming. The research also indicated shifts in ocean chemistry and a decrease in dissolved oxygen levels as additional impacts.

The assessment particularly identifies large whale species such as humpback and North Atlantic right whales as among the most vulnerable to climate alterations. Other toothed whales and dolphins were also found to be at considerable risk.

This research, recently published in the scientific journal PLOS ONE, serves as a critical indicator that existing U.S. management strategies for marine mammals must evolve to address the mounting challenges presented by climate change, argue marine mammal conservationists.

Matthew Lettrich, the lead author of the study and a biologist, noted that the research provides invaluable insights to federal ocean management bodies about safeguarding these at-risk animals. “As the climate is undergoing changes, we are witnessing some of its effects already. A substantial proportion of our marine mammal populations are distinctly susceptible to these climate-induced changes,” said Lettrich.

The study focused on marine mammals residing in the western North Atlantic Ocean, the Gulf of Mexico, and the Caribbean Sea. These animals are managed by the National Marine Fisheries Service, the federal entity responsible for the conservation and protection of marine resources.

The team of scientists assessed the marine mammals’ exposure to climate change and their capacity for adaptation. They found that 72% of the examined stocks are either highly or very highly vulnerable, with nearly half of these falling into the “very high” vulnerability category.

According to the study, one of the primary consequences of warming oceans is the impairment of marine mammals’ ability to locate food, along with a reduction in their habitable spaces. Furthermore, alterations in ocean temperature and chemistry have the potential to disrupt sound transmission, impacting the echolocation abilities of species like dolphins that rely on it for communication and hunting.

Regina Asmutis-Silvia, a biologist unaffiliated with the study, emphasized the need for political will to leverage these data in implementing protective measures. “While the U.S. possesses extensive data on marine mammals, such data become futile without the political will to enforce conservation measures,” she remarked.

The study underscores the importance of adopting a global perspective, as changes in climate affect not just specific species or local habitats but have far-reaching implications, said Laura Ganley, a research scientist unconnected to the study.

The assessment further states that climate change could influence the distribution and behavioral patterns of marine mammals. For instance, whales like the North Atlantic right whale, which undertake long migratory journeys annually, may require new forms of international cooperation for their protection.

Efforts by the federal government to protect declining whale populations have included new fishing restrictions and vessel speed limitations. However, these efforts face increasing challenges due to climate-induced alterations in oceanic conditions, leading marine mammals to venture outside protected zones, making them more vulnerable to threats like fishing gear entanglements and ship collisions.

“This study serves as a roadmap for ocean managers to prioritize those species most at risk from climate impacts,” said Gib Brogan, campaign manager with environmental group Oceana. “To preserve marine biodiversity, it is imperative that ocean management explicitly incorporate both current and prospective changes in oceanic conditions in their conservation strategies.”

For further updates, follow Patrick Whittle on X, previously known as Twitter: @pxwhittle

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Frequently Asked Questions (FAQs) about Climate Change and Marine Mammals

More about Climate Change and Marine Mammals

• NOAA Official Website
• PLOS ONE Journal Publication
• National Marine Fisheries Service
• Whale and Dolphin Conservation
• Anderson Cabot Center for Ocean Life at the New England Aquarium
• Oceana Official Website
• AP Climate Initiative