Bleaching effect: Coral loss threatens fisheries and livelihoods

Beneath the ocean’s surface, fisheries rely on the health of vibrant and complex ecosystems. Coral reefs, in particular, are the center of underwater life.

They provide essential food and shelter to countless marine species, making them crucial for maintaining marine biodiversity and ecosystem balance. Without coral reefs, many sea creatures would struggle to survive, threatening the entire marine environment.

But these individual ecosystems are in deep trouble. And that can have a ripple effect, impacting not just marine life, but human livelihoods too – particularly in the fisheries sector.

Coral decline affects fisheries

According to a recent study from the Woods Hole Oceanographic Institution (WHOI), a decline in live coral habitats directly influences the yield of marine fisheries.

The researchers explored the yield trends of nine fisheries in the vicinity of Australia’s iconic Great Barrier Reef from 2016 to 2020.

The team uncovered a worrying trend- significant losses could be the unfortunate reality if coral restoration efforts are not amped up.

In 2024, the Great Barrier Reef faced a severe bleaching episode, one of the worst in its history. During this event, an alarming 73% of surveyed reefs showed signs of bleaching, as per the Australian Marine Institute.

Coral bleaching: Threat to marine biodiversity

Coral reefs depend on microscopic algae, zooxanthellae, for survival and their bright hues. When ocean temperatures rise, the coral gets stressed and expels these crucial algae, leading to bleaching.

The persistent warming trend means the algae may not return, leaving the coral bleached and on the brink of death.

Over the past 30 years, a staggering 19% of the world’s coral reef area has been lost due to bleaching induced by ocean warming.

Fish and famine: Lives and livelihoods at risk

“This rapid loss of coral will force fish capable of living independently of them to move elsewhere. Less concentrated populations can lead to smaller yields for fisheries,” noted Marine (Yaqin) Liu, an environmental economist at WHOI.

When it comes to fish species that directly rely on reefs for food or shelter, like butterflyfish and coral trout, their yield will deplete in parallel with their population decline.

And it’s not just marine life at risk. Many fisheries, and the communities they support, are bound for turbulent waters.

The study pointed out coral trout and saddletail snappers, which heavily rely on outer-shelf reefs as their primary habitat, as the two most vulnerable fisheries.

If the live coral cover of the Great Barrier Reef reduces from 30% to 25%, the maximum sustainable yield of coral trout and saddletail snappers would drop by 8% and 19%, respectively.

An even steeper decline from 10% to 5% live coral cover could result in losses of 27% and a startling 56% for coral trout and saddletail snapper fisheries.

Coral decline: Economic impact on fisheries

These losses are not only ecological but economic. Professor Qingran Li, from Clarkson University in New York, shed light on the economic toll.

“Coral trout and saddletail snapper are part of Queensland, Australia’s line fishery, an industry with $27-31 million gross value,” said Professor Li.

“While this methodology of this study does not lend itself to making dollar predictions, we can expect a decline in fishing yields to have substantial economic impacts, such as loss of jobs and reduced export.”

Preserving coral reefs and fisheries

As coral reefs continue to battle warmer waters and bleaching events become more frequent, their role in nurturing marine life and safeguarding coastal communities from major storms becomes increasingly crucial. Their contribution to tourism and fishing revenues is equally significant.

These ecosystems also act as natural barriers, reducing the impact of storm surges and protecting vulnerable coastlines from erosion.

Data-driven climate change advocacy is so essential. “Responsible fisheries are already safeguarding coral reefs by integrating sustainable approaches, but human impacts like ocean warming and acidification further threaten coral reefs and fisheries yields,” said Liu.

“WHOI’s Reef Solutions Team continues study and develop innovative ways to restore and strengthen coral reefs, with a goal of taking successful learnings and implementing them globally.”

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