Unexpected hope for millions as bleached coral reefs continue to supply nutritious seafood
Coral reef ecosystems support diverse small-scale fisheries

Date:
January 6, 2022
Source:
Lancaster University
Summary:
Coral reef ecosystems support diverse small-scale fisheries -- and
the fish they catch are rich in micronutrients vital to the health
of millions of people in the tropics, a new study reveals. And,
counter- intuitively, following bleaching events that kill off
coral and can transform the composition of reef ecosystems, reef
fisheries can remain rich sources of micronutrients, even increasing
in nutritional value for some minerals. The findings show that the
availability of micronutrients from coral reef small-scale fisheries
may be more resilient to climate change than previously thought.



FULL STORY ========================================================================== Researchers studying coral reefs damaged by rising sea temperatures have discovered an unexpected 'bright spot' of hope for communities who depend
upon them for food security.


========================================================================== Coral reef ecosystems support diverse small-scale fisheries -- and the
fish they catch are rich in micronutrients vital to the health of millions
of people in the tropics, a new Lancaster University-led study reveals.

And, counter-intuitively, following bleaching events that kill off coral
and can transform the composition of reef ecosystems, reef fisheries can
remain rich sources of micronutrients, even increasing in nutritional
value for some minerals.

The findings, published today in the journal One Earth, show that the availability of micronutrients from coral reef small-scale fisheries
may be more resilient to climate change than previously thought. This
increased understanding is critical as continued global warming means
coral bleaching events are becoming more frequent and more severe,
placing greater stress on these vulnerable ecosystems.

Dr James Robinson, who led the study, said: "Our findings underline
the continuing importance of these fisheries for vulnerable coastal communities, and the need to protect against over-fishing to ensure
long-term sustainability of reef fisheries." The researchers also caution
that while these fisheries have proved more resilient to climate change disturbance than expected, continued understanding of the long-term
impacts of climate change to coral reef fisheries, and more data from
other regions, are urgent priorities.



==========================================================================
More than six million people work in small-scale fisheries that rely on tropical coral reefs. Their catches help to feed hundreds of millions
of coastal people in regions with high prevalence of malnourishment,
causing stunting, wasting and anaemia. However, until now, the nutritional composition of coral reef fish catches, and how climate change might
affect the nutrients available from reef fisheries, was not known.

This study, led by scientists from Lancaster University and involving an international team of researchers from the Seychelles, Australia, Canada
and Mozambique, benefitted from more than 20 years of long-term monitoring
data from the Seychelles, where tropical reefs were damaged by a large
coral bleaching event in 1998, killing an estimated 90% of the corals.

Following the mass-bleaching event, around 60% of the coral reefs
recovered to a coral-dominated system, but around 40% were transformed
to reefs dominated by seaweeds. These differences provided a natural
experiment for the scientists to compare the micronutrients available from fisheries on reefs with different climate-driven ecosystem compositions.

The scientists, who used a combination of experimental fishing, nutrient analysis, and visual surveys of fish communities in the Seychelles,
calculated that reef fish are important sources of selenium and zinc,
and contain levels of calcium, iron and omega-3 fatty acids comparable
to other animal-based foods, such as chicken and pork.

They also found that iron and zinc are more concentrated in fish caught
on reefs that have been transformed after coral bleaching and are now
dominated by macroalgae such as Sargassum seaweeds. These seaweeds have
high levels of minerals, which, researchers believe, is a key reason
why the algal-feeding herbivorous fishes found in greater numbers on transformed reefs contain higher levels of iron and zinc.

Dr Robinson said: "Coral reef fish contain high levels of essential
dietary nutrients such as iron and zinc, so contribute to healthy
diets in places with high fish consumption. We found that some micronutrient-rich reef species become more abundant after coral
bleaching, enabling fisheries to supply nutritious food despite climate
change impacts. Protecting catches from these local food systems should be
a food security priority." The researchers believe the results underline
the need for effective local management to protect the sustainability of
reef fisheries, as well as policies that retain more of reef fish catches
for local people and promote traditional fish-based diets. These can help
reef fisheries to best contribute to healthy diets across the tropics.

Professor Christina Hicks, a co-author on the study, said: "Fish are now recognised as critical to alleviating malnutrition, particularly in the
tropics where diets can lack up to 50% of the micronutrients needed for
healthy growth.

This work is promising because it suggests reef fisheries will continue to
play a crucial role, even in the face of climate change, and highlights
the vital importance of investing in sustainable fisheries management."
The study's authors include: James Robinson, Eva Maire, Nick Graham and Christina Hicks from Lancaster University; Nathalie Bodin from Seychelles Fishing Authority and Sustainable Ocean Seychelles; Tessa Hempson from
James Cook University and Oceans Without Borders; Shaun Wilson from the Department of Biodiversity, Conservation and Attractions in Australia, and Oceans Institute, Australia; and Aaron MacNeil from Dalhousie University.

========================================================================== Story Source: Materials provided by Lancaster_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. James P.W. Robinson, Eva Maire, Nathalie Bodin, Tessa N. Hempson,
Nicholas A.J. Graham, Shaun K. Wilson, M. Aaron MacNeil,
Christina C.

Hicks. Climate-induced increases in micronutrient
availability for coral reef fisheries. One Earth, 2022; DOI:
10.1016/j.oneear.2021.12.005 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/01/220106111544.htm

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