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Climate Extreme Intensifies Conflict Between People and Whales

November 29, 2021

New research aims to find win-win solutions to reduce whale entanglements in the West Coast Dungeness crab fishery.

Humpback whale entangled in gill net.

New research looks at how a climate extreme intensifies tensions between ocean life and people, and what can be done about it. The study was recently published in the Proceedings of the Royal Society of London B.

Researchers show that many strategies are insufficient during prolonged, anomalous warm water events called marine heatwaves. Instead, they recommend combining several approaches, including improved forecast systems, technological innovations, and understanding human behavior.

Over the past few years, marine heatwaves have dramatically affected natural resources along the U.S. West Coast, including economically valuable fisheries. Still, we know very little about how and when management actions can dampen their impacts on marine life and the people who rely on the ocean for their livelihoods.

An ecological pileup of recent unprecedented changes in the ocean off the West Coast led to record numbers of reported entanglements of humpback and other whales. These conditions put California’s Dungeness crab fishery, the region’s most valuable commercial fishery, at odds with the conservation of several at-risk whale species. 

Looking Back At Lessons Learned

Previous research looked into some of the ecological causes and effects of the spike in reported whale entanglements. Now researchers are asking how to approach this problem by balancing tradeoffs between a profitable and sustainable fishery and whale conservation. 

The researchers rewound the clock to understand how the marine heatwave affected fishing behavior and whale habitat. First, they looked back at how fishermen responded to the marine heatwave and associated fishing regulations. Second, they developed models to understand how whales responded to the extreme ocean conditions. They then used that past experience to explore a broad suite of potential solutions that could be implemented in the future. 

“Knowing what we know now, we can consider how fishing vessels and the whales adjusted at the time and use that to evaluate possible solutions,” said lead author Jameal Samhouri, Ecosystem Science Program Manager at NOAA’s Northwest Fisheries Science Center. 

Graphic showing the effectiveness of management scenarios (like fisheries season delays and gear reductions) during a normal season where there are more "win-wins" for both whales and the crab fishery. However, the same management scenarios, when applied during a heat wave, don't work as well: we see fewer win-wins for both whales and the crab fishery compared to a normal season.
Credit: Su Kim/NOAA Fisheries

Climate Change Makes Win-Win Solutions Harder to Find

Researchers say this extreme climate event made “win-win” solutions for protecting whales and fishing activity harder to find than they are during more normal conditions. “This example shows how climate change exacerbates the difficult tradeoffs managers have to weigh,” said Briana Abrahms, a coauthor from the University of Washington.

“As challenging as the marine heatwave was, there remains a lot to be learned from it,” continues Abrahms. “Understanding the role that climate extremes play in balancing the needs of people and species conservation can help anticipate and plan for those tradeoffs in the future.”

Man with white hair and goatee hauling up a net full of crab from the side of a boat at sea.
Crab haul. Photo credit: Benjamin Drummond/bdsjs.com

These are real-world decisions that state managers in California are considering even now, as they decide when and where to open the 2022 Dungeness crab fishing season. The researchers hope they can help managers lessen the negative social and economic impacts of those decisions on fishermen while also minimizing the whale entanglement risk.

Early Warning System

While not exhaustive, the researchers came up with several potential considerations for improving future decision-making. One idea is to provide fishermen and managers with an early warning system. Recently, scientists and managers working on this issue realized certain ocean conditions increased the likelihood of whale entanglements. So they’ve created a website to help make that information available to fishermen in near real-time. The hope is that better communication can help fishermen avoid fishing when and where the risk of entanglement is high. 

Creating Incentives

Another potential solution is to create incentives for fishermen and managers. “Suppose we really understand why people are deciding to fish in a place that does or doesn’t have the potential for a whale to get caught,” said Samhouri. “In that case, we can provide incentives and information that could encourage or nudge them toward a win for both the fishermen and the whales.” 

Technological Solutions

Fishermen are also exploring technological solutions. For example, lobster fishermen along the East Coast are experimenting with ropeless fishing gear to help reduce entanglements with endangered North Atlantic right whales. If feasible, such an innovation may be another tool for Dungeness crab fishermen to consider.  

“We have an idea about what it might take to solve this problem,” said Samhouri, “but there isn’t a simple fix. 

Researchers for the study included experts from: 

  • NOAA Fisheries Northwest Fisheries Science Center
  • NOAA Fisheries Southwest Fisheries Science Center
  • NOAA Fisheries West Coast Regional Office
  • University of Washington
  • New England Aquarium