Climate change to slash seafood nutrients by 30% in low-income countries

The nutrients available from seafood could drop by 30 per cent for low-income countries by the tip of the century as a consequence of climate change, suggests recent UBC research.

That is in a high carbon emissions and low mitigation scenario, in response to the study published today in Nature Climate Change. This may very well be reduced to a roughly 10 per cent decline if the world were to fulfill the Paris Agreement targets of limiting global warming to 1.5 to 2 degrees Celsius – which recent reports have shown we’re not on the right track to attain.

Low-income countries and the worldwide south, where seafood is central to diets and has the potential to assist address malnutrition, are the toughest hit by the consequences of climate change. For a lot of, seafood is an irreplaceable and reasonably priced source of nutrients.”

Dr. William Cheung, first writer, professor and director of the UBC Institute for the Oceans and Fisheries (IOF)

The researchers examined historical fisheries and seafood farming, or mariculture, databases including data from UBC’s Sea Around Us to search out out quantities of key nutrients that were available through fisheries and seafood farming up to now, and used predictive climate models to project these into the longer term. They focused on 4 nutrients which can be plentiful in seafood and necessary to human health: calcium, iron, protein and omega-3 fatty acids, the latter of which is just not available in other food sources.

They found that the provision of those nutrients peaked within the Nineties and stagnated to the 2010s, despite increases provided by farming seafood, and from fishing for invertebrates equivalent to shrimp and oysters.

Calcium sees biggest decline

Trying to the longer term, the provision of all 4 nutrients from catches is projected to diminish, with calcium the toughest hit at a projected decline of about 15 to 40 per cent by 2100 under a high and low emissions scenario, respectively. Omega-3 would see an roughly five to 25 per cent decrease. These declines are largely driven by decreases within the amounts of pelagic fish available for catch.

“Small pelagic fish are really wealthy in calcium so in areas of the world where people have intolerances to exploit or where other animal-sourced foods, like meat and dairy, are rather more expensive, fish is basically key to people’s diets,” said senior writer Dr. Christina Hicks, professor at Lancaster University. “In lots of parts of the world, particularly low-income countries across the tropics, fish supply nutrients which can be lacking in people’s diets.”

While seafood farming will contribute more nutrients in the longer term compared with current levels, the researchers projected these increases wouldn’t find a way to compensate for the loss from fisheries. Under a high emissions scenario, any gains in the provision of nutrients from seafood farming before 2050 could be lost by 2100.

“The first reason for that is climate change, which can also be a big threat to seafood farming, leaving us with a growing dietary deficit,” said co-author Dr. Muhammed Oyinlola, a postdoctoral fellow within the UBC department of zoology and the Institut national de la recherche scientifique. “Seafood farming alone cannot provide a comprehensive solution to this complex issue.”

The provision of all 4 nutrients from tropical waters of generally lower income nations, equivalent to Indonesia, the Solomon Islands and Sierra Leone, is projected to say no steeply by the tip of the century under a high emissions scenario, compared with minimal declines in higher income, non-tropical waters, equivalent to those of Canada, the U.S. and the U.K.

Globally, the researchers projected that seafood-sourced nutrient availability would decrease by about 4 to seven per cent per degree Celsius warming. For lower-income countries across the tropics including Nigeria, Sierra Leone, and the Solomon Islands, the projected decline was two to thrice this global average at nearly 10 to 12 per cent per unit of warming.

“This research highlights the impact of each degree of warming,” said Dr. Cheung. “The more we are able to reduce warming, the less risks to marine and human life.”

Using all of a fish

Certain kinds of fish equivalent to anchovies and herring are filled with nutrients but often used for fish meal and fish oil because these nutrients also promote fish growth. Similarly, many countries retain only select parts of a fish on the market. The researchers highlighted potential adaptations to extend nutrient availability from seafood, by retaining more of those nutritious fish for local human consumption, in addition to reducing food waste in fisheries production and consumption by utilizing all parts of a fish including the top and fins.

“The longer term development of seafood supply needs to contemplate the dietary security of vulnerable groups, not only economic profit,” said Dr. Cheung. “But there is a limit to how effective these interventions are, so it is important to limit global warming as much as possible.”