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Marine heat waves are persisting in the U.S., even in winter

Despite the onset of winter, the United States is still dealing with marine heat waves that could potentially harm fish stocks, according to a report from the Marine Stewardship Council (MSC). 

Recent data from NOAA reveals that marine heatwaves are prevalent across various U.S. coasts, including the Pacific Northwest, the south Gulf of Mexico, and the Northwest Atlantic. Central America is also experiencing these heatwaves off both of its coasts. 

Widespread warming

NOAA’s marine heat wave forecast department predicts a 60 percent chance of these warmer conditions persisting for the next four to six months.

As of today, 30% of the global ocean is experiencing marine heatwaves. This is the largest combined ocean area to undergo such warming since 1991, encompassing regions like the northwest Pacific, Sea of Japan, Caribbean Sea, tropical and northern Atlantic, western Indian Ocean, and parts of the Southern Ocean in the Indian, Pacific, and Atlantic sectors.

Significant challenges 

“Marine heat waves, estimated to have increased by more than 50% in the past 30 years, combined with larger-scale warming caused by climate change are having a profound impact on our oceans,” said Nicole Condon, the MSC’s US Program Director.

“As a result, the size and distribution of the world’s fish populations is changing, creating significant challenges for fisheries managers. However, this also creates an opportunity to build more resilient management systems to support the future of fisheries.”  

Impact on fish 

The MSC noted that certain fish species, such as the black sea bass on the U.S. east coast and groundfish on the west coast, are increasingly vulnerable to climate change

The fish are migrating northward in search of cooler waters. This shift in fish distribution necessitates cooperative efforts across U.S. states for effective monitoring and management of shared fish stocks.

Sustainable management 

The MSC is exploring various options for managing shifting fish stocks, such as the black sea bass. 

Climate-smart fisheries management solutions aim to adjust fishing quotas for different states automatically as stocks migrate northwards, ensuring sustainable management across state boundaries.

Consequences of warming seas

Warming ocean waters may impede the ability of some fish species to spawn, potentially leading to a decline in fish numbers, affecting seafood supplies and ocean ecosystems. 

Scientists warn of the possibility of repeating past events, citing the 2014-2016 U.S. West Coast marine heat waves that drastically reduced fish populations. Fisheries closed for more than three years to help rebuild fish stocks.   

“In the last decade, marine heatwaves have disrupted fisheries all around the world. If conditions stay hot, similar catastrophes may be on the horizon,” said Dr. Christopher Free, Marine Institute, University of California, Santa Barbara.

Broader implications 

Furthermore, a recent study indicated that the socio-economic costs of a single marine heatwave event could be substantial, with direct losses exceeding US$800 million or US$3.1 billion in indirect losses of ecosystem services for multiple years.

The combined impact of these ongoing marine heat waves and the overall warming of seas due to climate change poses a significant threat to major fish species in the United States.

This situation calls for urgent action from governments to prioritize sustainable management of fish stocks to mitigate the impacts of climate change, including heatwaves and warming waters.

MSC Fisheries standard

“Policy makers must find a way to incorporate stock shift changes and climate smart solutions into long-term and robust fisheries management plans. MSC certified fisheries showcase that meaningful steps in this direction are possible,” said Condon.  

“The MSC Fisheries standard, along with the roughly 15% of global fisheries volume currently MSC certified, helps to safeguard seafood supplies and broader ocean health. It will take all of us recognizing and planning for continued shifts to foster oceans teeming with life for future generations.”

The Marine Stewardship Council (MSC) is a global nonprofit organization that works to end overfishing and set standards for sustainable fishing around the world.

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