As global temperatures continue to rise, massive bleaching of coral reefs in the tropics will become more common. These reefs are home to an incredible diversity of marine life, so any damage to them could be catastrophic.
We knew that, but new study done by scientists at Lancaster University in the UK offers a ray of hope for the hundreds of millions of people who depend on tropical reefs across the world for their nutrition.
Small-scale fisheries, scientists say, may be more resilient to climate change than previously thought, the researchers explain.
Even better
Even after major bleaching events, reef fisheries can still be a rich source of micronutrients. In fact, they can increase the nutritional value of some important minerals like iron and zinc, scientists have found.
Scientists came to this conclusion after analyzing the nutrient content of 43 species of tropical reef fish in the Seychelles, where a large-scale bleaching event in 1998 destroyed 90% of the local corals.
Over time, about 60% of the area’s coral reefs recovered, while the rest became algae-dominated reefs, allowing scientists to compare the availability of micronutrients in the reefs with these different compositions. Based on their findings, they report that “coral reef fish contain similar levels of iron, selenium, and zinc as chicken, pork, and beef, and higher levels of calcium and omega-3 fatty acids.”
Algae and reefs
Specifically, iron and zinc were more concentrated in reef-caught fish that were transformed after massive bleaching in marine ecosystems dominated by macroalgae such as algae. They are seaweed they have high levels of essential minerals, so the herbivorous fish that feed on them end up containing higher levels of iron and zinc. By eating these fish, people, in turn, can access these minerals in their diets.
“The pieces of coral reefs contain high levels of essential dietary nutrients, such as hierro and zinc, which contribute to healthy diets in places with high consumption of fish”, says James Robinson, scientist at the Environmental Center for the University.
“We found that some micronutrient-rich reef species become more abundant after coral bleaching, allowing fisheries to provide nutritious food despite the impacts of climate change. Protecting the catch of these local food systems must be a food security priority,” explained Robinson.
“More than six million people work in small-scale fisheries that rely on tropical coral reefs. Their catches help feed hundreds of millions of coastal people in regions with a high prevalence of malnutrition, leading to stunting, wasting and anemia.
“However, until now, the nutritional composition of coral reef fish catches and how climate change may affect the nutrients available in reef fisheries were unknown,” they add.
Said that…
Overfishing, pollution and other stressors also pose serious threats to many reefs in the tropics, and more data is also needed on how reefs elsewhere are doing in the face of rising water temperatures.
Importantly, tropical reefs will need to be better managed and protected so they can continue to provide local people with sustainable sources of fish for their traditional fish-based diets, experts emphasize.
“Fish is now recognized as key to alleviating malnutrition, particularly in the tropics, where diets can lack up to 50% of the micronutrients needed for healthy growth,” said Professor Christina Hicks, co-author of the study.
Reef fisheries can continue to play a crucial role in the diets of people in coastal communities even in the face of climate change, but investing in sustainable fishing practices will be critically important, Hicks added.
By Daniel T. Cross. Article in English