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Tuesday, July 20, 2021 (Halifax, NS) Millions of people around the world could face an increased risk of malnutrition as climate change threatens their nutrient-rich local fisheries, according to an extensive study out today.

New projections examining more than 800 fish species in almost 160 countries have revealed how two growing pressures – climate change and overfishing – could affect the availability of vital micronutrients in our oceans. 

Analyses by an international team of scientists from Dalhousie University, the University of British Columbia and Lancaster University in the UK reveal that climate change is one of the most extensive threats to the supply of essential micronutrients from marine fish catches and jeopardizes the supply of micronutrients from fisheries in 40 per cent of countries.

“As climate change and overfishing are significant pressures on global fish stocks, it is essential for the dietary requirements of millions of people to know the extent that these pressures will have on the availability of micronutrients in our seas in the future,” says Dr. Eva Maire of Lancaster University and lead author of the paper, published in Current Biology.

“We have shown that climate change is the most pervasive threat to the supply of vital micronutrients for many countries around the world, and in particular in the tropics.”

Fisheries micronutrient supplies were found to be less vulnerable to overfishing.

In addition to omega-3 fatty acids, fish are an important source of iron, zinc, calcium and vitamin A. A lack of these vital micronutrients is linked to maternal mortality, stunted growth and pre-eclampsia.

Countries at risk of losing this source of micronutrients from climate change include East Asian and Pacific countries, such as Malaysia, Cambodia, Indonesia and Timor Leste, as well as Sub-Saharan African countries such as Mozambique and Sierra Leone. Deficiencies in calcium, iron, zinc, and vitamin A are particularly prevalent in the tropics.

This study draws on the FishNutrients model, a finfish nutrient composition database released recently. 

“These data open up a whole new area of research and are crucial to address global food security challenges,” says co-author Dr. Aaron MacNeil, associate professor in the Ocean Frontier Institute at Dalhousie University. “Our research shows that efforts to improve food security and tackle malnutrition need to integrate fisheries, climate and food policies to secure these micronutrients for existing and future generations.”

A key reason why climate change is such a threat comes down to the species of fish that countries are catching. Some fishers in tropical nations are targeting micronutrient-dense species that have an increased vulnerability to climate change, such as Indian and short mackerels, bonga and hilsa shads, and dolphinfish.

Previous studies have shown that fish are unequal when it comes to their nutritional content. A range of factors, such as diet, sea water temperature and energetic expenditure influence how many micronutrients fish contain. Tropical fish tend to be richer in micronutrients than cold water species.

“As well as highlighting the growing threat of climate change to the food security of millions of people, our study also offers hope for the future,” says co-author Dr. William Cheung, a professor at the University of British Columbia.

“Armed with nutritional information about different fish species, many countries have the capacity to adapt their fisheries policies to target different, more resilient fish species. By doing this, these nations can ensure a more reliable supply of micronutrients for their people.”

This research was funded by the European Research Council, the Royal Society, the Leverhulme Trust and NSERC Canada.

Please find images and credit information here.

Media contact:
Alison Auld
Senior Research Reporter
Dalhousie University
Cell: 1-902-220-0491
Email: alison.auld@dal.ca