Lessons from ‘The Blob’ to help manage fisheries during future marine heatwaves

In early 2014, a huge anomaly descended on the seas: a patch of warm water that manifested in the Gulf of Alaska. Scientists named it “The Blob.”

A strong El Niño prolonged this marine heat wave into 2016. It spread as far south as Baja California, Mexico, wreaking havoc on marine ecosystems, weather patterns, and fisheries. Now that the heat wave is over, researchers have begun to examine its effects and gain information that can help us prepare for a future in which marine heat waves are more common and intense.

Marine scientist Chris Free of UC Santa Barbara led a network of colleagues along the West Coast to investigate how the 2014-2016 marine heat wave affected the region’s fish, fisheries and anglers. They documented the various effects of The Blob through an economic synthesis along the coast and a series of 10 case studies, finding that many fisheries suffered due to declining populations and changing ranges.

However, even some of the species that did well created management challenges. The study, published in the journal fish and fishingpresents an outline of what to prioritize as scientists, fishermen and policy makers chart a way forward.

“Marine heat waves have really emerged as possibly the biggest immediate climate threat to the oceans,” said lead author Lyall Bellquist, a fisheries scientist at UC San Diego and The Nature Conservancy. They are already increasing in frequency, intensity and duration, he noted, causing profound impacts on ecosystems and economies, communities and cultures around the world.

The Blob was the largest marine heat wave on record globally, impacting the entire food web between Mexico and Alaska, from plankton to whales. “Ecosystems are really complex and really connected,” said lead author Free, “so a change in one place can just radiate and cause surprising change in another place.”

Winners, losers and headaches of both

To make sense of such a large shock, the team analyzed fishing revenue before, during, and after the heat wave, which led them to case studies that highlight different responses to the event.

The ocean undergoes oscillations that modify the distribution of currents, temperatures and nutrients. Periodic events such as El Niño mean scientists, fishermen and resource managers are familiar with the effect warmer water can have on different species. But massive heat waves like The Blob don’t always match our expectations.

Consider anchovies and sardines. The two species have a similar ecological niche, but sardines were thought to prefer warmer temperatures than anchovies. And yet, Pacific sardine stocks collapsed before and during The Blob, leading to a multi-year federal fishing disaster and closure from California to Washington.

Meanwhile, anchovy began to rise during the marine heat wave and exploded to near-record levels in subsequent years. “You can hike up to the cliffs at Torrey Pines and see schools of anchovies from La Jolla to Del Mar,” Bellquist said.

Scientists with the National Marine Fisheries Service are working to understand what “went right” for anchovy during warm years and why they continue to increase, including studies on diet and adult and larval survival. Marine mammals and birds that eat anchovy have generally thrived since 2016. Surprises like these will become more common and disturbing, the authors explained, so we need to figure out why we were wrong and what to do about it.

Climate changes can also produce results that seem completely unconnected. For example, the researchers found an increase in whale entanglements during The Blob. A heat wave can reduce the amount of cold, nutrient-rich water that rises from the depths. This depletes the stock of krill on the high seas, which large whales typically hunt. Marine mammals likely moved inshore in search of booming anchovies, where they overlapped more than usual with the Dungeness crab fishery, leading to increased entanglements in commercial traps.

The study also highlighted that some fisheries will fluctuate as ocean conditions change. The distribution of market squid, generally a warm-water species, shifted toward Oregon during the heat wave, with activity as far north as Kodiak, Alaska. “For context, market squid is the highest volume fishery in the entire state of California,” Bellquist said.

If managed properly, squid could be a new and high value fishery in these areas. But development also presents challenges: the species could change the ecosystem, create bycatch problems, or alter the prey base available to other target species.

Even success stories can create management challenges. Shortbelly rockfish flourished in The Blob’s warm embrace. And while historically not a target species, it still impacted fisheries. The increase in abundance nearly shut down the Pacific hake fishery just two weeks into the season due to increased redfish bycatch.

But better control averted catastrophe. “Based on the best available data, they were able to adjust the bycatch limit to allow the hake fishery to continue to operate,” Free said. “This is a good example of management being really agile and flexible and responding quickly as we need to see more in the future.”

planning for the future

The case studies highlight the actions we need to take to prepare for a warmer and more volatile future. “Marine heat waves are here to stay,” Free said. Even if we could perfectly predict and manage them, they would still affect fish and fisheries. “We need policies that strengthen the resilience of fishing communities in the face of negative impacts that we cannot mitigate.”

Improving the monitoring of fisheries will allow us to detect changes earlier and make decisions more quickly. “Without the monitoring data, we would have had no scientific justification for allowing a higher catch limit for short-bellied rockfish and the hake fishery would have been closed,” Free said.

Management models should also include climate components, the authors stated. “Reactive management approaches that are based solely on historical fisheries analysis will only get us so far,” Bellquist said. Instead, we need to integrate forecasts of how fisheries might respond to both management decisions and climate change.

The authors also recommended making permits easier to access so that anglers can target a more diverse portfolio of species. The more permits a fisherman has, the better he can target a species that is doing well.

Innovation will also play a crucial role in the future of fishing. Free and Bellquist spoke highly of exempt fishing permits, which allow fishermen to partner with scientists and legally operate under different rules or with different gear. “It could allow fishermen to try to solve the problem themselves,” Free said.

Permits could spur innovation to reduce bycatch. One successful example of this was the recent federal approval of deep-submersion buoy kits, which were jointly developed by fishermen and scientists to reduce sea turtle bycatch in the swordfish fishery. Improvements like this show what is possible when stakeholders work together.

The authors are also evaluating fishing insurance as a possible tool to supplement federal assistance for fishing disasters. People get their food primarily from one of three sources: farms, ranches, and oceans, and climate change has affected each. But unlike agriculture and ranching, there are currently no fishing insurance programs in the US, Bellquist explained. Such programs could help alleviate the impacts of extreme events and were recently recommended by the National Oceanic and Atmospheric Administration.

Fortunately, the government is already updating the protocol for federal fishing disasters. In late 2022, Congress enacted the Fisheries Disaster Improvement Act. The new legislation is intended to streamline the disaster assistance determination process. It also contains provisions to study the social impacts of disasters, rebuild affected fisheries, and prevent future disasters, among other elements.

The authors are now working on step-by-step instructions for navigating to some of their recommendations. For example, they are developing a computer model to simulate management strategies to prevent weather-induced whale entanglements in the Dungeness crab fishery. Biotoxin modeling tools will also guide managers, fishers and farmers during harmful algal blooms, which are likely to worsen with climate change. “We’re also identifying fisheries that are good candidates for insurance programs,” Free said, “and designing programs that would be effective and affordable for fishermen.”