UW News

June 15, 2016

Falling fish catches could mean malnutrition in the developing world

UW News

The world won’t be able to fish its way to feeding 10 billion people by midcentury, but a shift in management practices could save hundreds of millions of fish-dependent poor from malnutrition, according to a new analysis by researchers at Harvard, the University of Washington and other universities that utilizes new databases on global fish catch and on human dietary nutrition.fishing

At its heart, the problem is a simple one of supply and demand: Global fish catches peaked in 1996, while the Earth’s human population is expected to rise through 2050, from the current 7.3 billion to between 9 billion and 10 billion.

But that straightforward dynamic oversimplifies a problem also affected by natural processes, economic pressures, international regulations and human health needs.

Lead author Christopher Golden, research scientist at the Harvard T.H. Chan School of Public Health and associate director of the Planetary Health Alliance, said that it is important to include human nutrition, along with biodiversity preservation and economic considerations, in determining how fisheries are managed.

The work estimates that, in the coming decades, 11 percent of the global population — 845 million people — is vulnerable to micronutrient deficiencies due to its reliance on seafood, a figure that climbs to 19 percent, or 1.39 billion people, if nutrients only found in animal sources, such as vitamin B12 and DHA omega-3 fatty acids, are included.

Co-author Edward Allison, a professor in the UW’s School of Marine and Environmental Affairs, said fish usually are considered to be a good source of protein. Perhaps more important, however, are the micronutrients found in fish and other seafood, particularly in poor nations where there may not be another source to get these necessary nutrients.

“We are able to quantify for the first time what supply and availability of a major food group such as fish and seafood means for maintaining the health of populations that are vulnerable to nutrient deficiencies,” Allison said.

Fish provide often overlooked micronutrients, including vitamin B12, iron and zinc. According to the report, published June 16 as a commentary in the journal Nature, micronutrient deficiencies can affect maternal mortality, child mortality, cause cognitive defects, and impact immune function. Some 45 percent of mortality in children under age 5 is attributable to undernutrition.

The report says that the vulnerability of these poor, fish-dependent populations in the tropics has been underestimated and that these are the very places whose fish resources are under the most intense pressure.

The analysis of two new databases, one from the Sea Around Us research initiative at the University of British Columbia and the other from a team led by Samuel Myers at Harvard, says that those most likely to suffer the impact of fisheries’ decline are the global poor, particularly those for whom fish make up a significant part of their diet.

“We’re missing an enormous piece of this picture, because many of the consequences of the way we manage resources and conserve natural systems will have very strong and powerful downstream effects on human health,” said Golden, of Harvard. “It’s not just a biodiversity issue, it’s not just an economics issue. We need to be really thinking through this third dimension, human health and well-being.”

Golden said those in industrialized nations can compensate for the nutritional gap left by a decline of fish in the diet. They can afford to buy replacement foods, supplements, and vitamins, while those in developing nations often have few alternatives.

The Planetary Health Alliance officially launched in January in partnership with the Wildlife Conservation Society and with support from The Rockefeller Foundation. The study was conducted under joint leadership of Harvard, the University of British Columbia, the UW, and the University of California at Santa Barbara.

The research was supported by the Wellcome Trust, through the “Our Planet, Our Health” initiative and the National Socio-Environmental Synthesis Center.


This was adapted from a Harvard news release.