Nature Archives - Saving Seafood

Critique of No-Take MPA Study Published by Nature

July 8, 2022 — Last year, Sala et al. 2021 made waves in both the scientific community and mainstream press with its publication in Nature. The paper claimed that increasing MPAs to stop fishing would lead to more seafood harvest, more biodiversity, and a reduced carbon footprint—a true win-win-win for the ocean. The press release that accompanied the paper highlighted an eye-popping statistic that bottom trawling released more carbon than all airline travel; stories covering Sala et al. 2021 appeared in hundreds of press outlets worldwide.

However, the three computer models used to make each of the “win-win-win” claims have been under increased scrutiny and many scientists doubt their conclusions.

It started with the food provisioning model initially published in the Proceedings of the National Academy of Sciences (PNAS) in 2020. Inexplicable assumptions in the model and several data errors were missed by an inadequate peer review—likely due to a conflict of interest by the PNAS editor. The journal retracted it in October 2021.

You can read the whole breakdown of the retraction and the science of the food model here.

Retractions are rare in science and generally only used in cases of misconduct. Poor science is hardly ever retracted for its flaws—instead, it gets officially criticized and/or updated in the literature.

That process has now started for Sala et al. 2021, with the first official critique (and response) published today in Nature (though several critiques have been available on preprint servers).

The comment, by Ray Hilborn (founder of this site) and Michel Kaiser, points out inconsistent parameters and assumptions and criticizes the overall approach to global MPA science and advocacy.

According to Hilborn and Kaiser, the most severe flaw in Sala et al. 2021 is the inconsistent accounting of fishing effort in the author’s MPA scenarios.

In the carbon and biodiversity model, Sala et al. assumes that when an area is placed into an MPA, the fishing effort that was previously there disappears. But, in the food provisioning model, the paper assumes fishing effort moves to other areas open to fishing. This upwardly biases their claims that MPAs could simultaneously reduce carbon footprint, improve biodiversity, and increase catch:

In their calculations of biodiversity conserved and CO2 emissions reduced, the authors assume that fishing effort disappears, which would decrease total harvest at the point when the MPAs are established. Yet in the base case for the fisheries harvest section, the authors assume that fishing effort moves to areas open to fishing, keeping fishing harvests high.

MPAs certainly reduce fishing effort inside a protected area, but in the real world, fishing effort does not simply disappear—it moves outside the MPA to places where fishing is still allowed. In this scenario, the benefits to carbon emissions and biodiversity presented in Sala et al. would significantly decrease, perhaps even show a net negative response because:

Fishing effort generally goes to places with high catch rates, and if forced to fish elsewhere, more effort is required to achieve the same catch.

In their response to Hilborn and Kaiser, the original authors acknowledge that the attention-grabbing statistic in the press release that bottom trawling releases more carbon into the ocean than all airline emissions would only be true if fishing effort disappears.

Though it garnered big headlines and more attention than any other ocean science paper of the last few years, Sala et al. 2021 does a disservice to marine conservation with its analysis based on incomplete data and erroneous assumptions. Policy that follows its recommendations would potentially waste conservation effort and money on strategies that would not deliver on goals, e.g., proposing a network of MPAs where fisheries are already well managed.

Read the full story at Sustainable Fisheries UW

New global forecasts of marine heatwaves foretell ecological and economic impacts

April 22, 2022 — Researchers have developed global forecasts that can provide up to a year’s notice of marine heatwaves, sudden and pronounced increases in ocean temperatures that can dramatically affect ocean ecosystems.

The forecasts described in the journal Nature could help fishing fleets, ocean managers, and coastal communities anticipate the effects of marine heatwaves. One such heatwave, known as “the Blob,” emerged about 2013 in the northeast Pacific Ocean and persisted through 2016. It led to shifting fish stocks, harmful algal blooms, entanglements of endangered humpback whales, and thousands of starving sea lion pups washing up on beaches.

“We have seen marine heatwaves cause sudden and pronounced changes in ocean ecosystems around the world, and forecasts can help us anticipate what may be coming,” said lead author Michael Jacox, a research scientist at NOAA Fisheries’ Southwest Fisheries Science Center in Monterey, California, and NOAA’s Physical Sciences Laboratory in Boulder, Colorado.

Marine heatwave forecasts will be available online through NOAA’s Physical Sciences Laboratory. The researchers called the forecasts a “key advance toward improved climate adaptation and resilience for marine-dependent communities around the globe.”

Read the full story at ScienceDaily

‘Blue Food Revolution’ to Tackle Climate Change and Malnutrition

September 22, 2021 — Doubling of global demand for aquatic foods calls for a ‘blue food revolution’ to tackle climate change and malnutrition, new research argues.

An unprecedented review of the aquatic foods sector has uncovered how fisheries and aquaculture can play a greater role in delivering healthy diets and more sustainable, equitable and resilient food systems around the world.

Five peer-reviewed papers in the journal Nature highlight the opportunities to leverage the vast diversity of aquatic, or “blue,” foods in the coming decades to address malnutrition, lower the environmental footprint of the food system, and provide livelihoods.

“People are trying to make more informed choices about the food they eat, in particular the environmental footprint of their food,” said Ben Halpern, a marine ecologist at UC Santa Barbara’s Bren School of Environmental Science & Management, who with colleagues examined the environmental sustainability of aquatic foods, the potential for the growth of small-scale producers and the climate risks that face aquatic food systems. “For the first time we pulled together data from hundreds of studies on a wide range of seafood species to help answer that question. Blue foods stack up really well overall and provide a great option for sustainable food.”

The research projects that global demand for blue foods will roughly double by 2050, and will be met primarily through increased aquaculture production rather than by capture fisheries.

Investing in innovation and improving fisheries management could increase consumption even more and have profound effects on malnutrition. For instance, a “high growth” modeling scenario showed that increasing supply by 15.5 million tons (8%), causing a drop in prices, would reduce cases of nutrient deficiencies by 166 million, especially among low-income populations.

Read the full story at ECO Magazine

The oceans’ circulation hasn’t been this sluggish in 1,000 years. That’s bad news.

April 11, 2018 — The Atlantic Ocean circulation that carries warmth into the Northern Hemisphere’s high latitudes is slowing down because of climate change, a team of scientists asserted Wednesday, suggesting one of the most feared consequences is already coming to pass.

The Atlantic meridional overturning circulation has declined in strength by 15 percent since the mid-20th century to a “new record low,” the scientists conclude in a peer-reviewed study published in the journal Nature. That’s a decrease of 3 million cubic meters of water per second, the equivalent of nearly 15 Amazon rivers.

The AMOC brings warm water from the equator up toward the Atlantic’s northern reaches and cold water back down through the deep ocean. The current is partly why Western Europe enjoys temperate weather, and meteorologists are linking changes in North Atlantic Ocean temperatures to recent summer heat waves.

The circulation is also critical for fisheries off the U.S. Atlantic coast, a key part of New England’s economy that have seen changes in recent years, with the cod fishery collapsing as lobster populations have boomed off the Maine coast.

Some of the AMOC’s disruption may be driven by the melting ice sheet of Greenland, another consequence of climate change that is altering the region’s water composition and interrupts the natural processes.

Read the full story at the Washington Post

Closing parts of the ocean to fishing not enough to protect marine ecosystems

July 18, 2016 — A University of Washington fisheries professor argues that saving biodiversity in the world’s oceans requires more than banning fishing with marine protected areas, or oceanic wilderness areas. In a three-page editorial published in the journal Nature, he argues that this increasingly popular conservation strategy is not as effective as properly managing recreational and commercial fisheries. “There’s this idea that the only way you can protect the ocean is by permanently closing parts of the ocean to fishing, with no-take areas,” said Ray Hilborn, a professor in the UW’s School of Aquatic and Fishery Sciences. “You protect biodiversity better by regulating fisheries over the country’s entire economic zone.”

Marine protected areas have grown in popularity since the early 2000s. Recent examples include an area twice the size of Texas in the central Pacific established in 2014 by President Barack Obama, and a proposal to close 25 percent of the Seychelles’ exclusive economic zone, an island nation off Africa’s east coast.

Several environmental organizations have set a longer-term goal of making 30 percent of the world’s oceans into no-take marine protected areas by the year 2030. But Hilborn believes this is not the best way to protect global marine ecosystems.

“If the problem is overfishing or bycatch, then fisheries management is much more effective than establishing MPAs because you regulate the catch over the entire economic zone,” Hilborn said. “I don’t see how anyone can defend MPAs as a better method than fisheries management, except in places where you just can’t do management.”

In countries with functioning fisheries management systems, Hilborn believes, conservationists and the fishing industry should work together on large-scale protection of marine biodiversity and sensitive marine habitats.

Read the full story at Science Daily

1 in 10 people may face malnutrition as fish catches decline

July 1, 2016 — There are many important reasons to manage the world’s wild fisheries. We do it to maintain stock levels, to ensure biodiversity and because fish are valuable. But researchers say there’s something else in need of protection: The very people who rely on fish for food.

Scientists are predicting more than 10 percent of the world’s population, a whopping 845 million people, will experience deficiencies in critically important micronutrients including zinc, iron, vitamin A, vitamin B12, and fatty-acids in the coming decades if global fish catches continue to decline.

Christopher Golden, lead author and research scientist at Harvard School of Public Health, calls it “a perfect storm” for countries like Indonesia, the Philippines, Malaysia, the Maldives, Angola, Ghana, Nigeria and others that rely heavily on wild-caught fish for sustenance, and cautions the findings are just “the tip of the iceberg.”

It’s in these regions, close to the Equator, where nutrition is highly dependent on wild seafood, and where fisheries are “most at risk from illegal fishing, weak governance, poor knowledge of stock status, population pressures and climate change,” Golden and his co-authors warn in a commentary in the journal Nature. “These countries urgently need effective strategies for marine conservation and fisheries management to rebuild stocks for nutritional security.”

Up until now, they say, studies have focused only on protein loss from lack of seafood — overlooking how micronutrient loss could greatly impact health, says Golden.

We humans need micronutrients in only tiny amounts, but our bodies still require them for good health, explains Ashley Koff, a Washington, D.C.-based registered dietitian. Zinc, for example, is important for immune health. Iron is critical for bringing oxygen into red blood cells, helps prevent anemia and for children, it’s important for total body growth. Fatty acids are essential for brain growth and development.

“While they’re micro, they play a significant role in reproductive and overall health,” she says.

Read the full story at Minnesota Public Radio