Kuala Lumpur, Malaysia - The Malaysian Fisheries Department revealed on Sunday that upwards of half the country's coral reefs had been bleached due to rising ocean temperatures.

In a statement to the press on Sunday, the Department of Fisheries in Malaysia revealed that an assessment taken between April and June this year had found that more than half the country's reefs had been bleached, AFP reports.

Coral bleaching can be caused by a number of different factors, including agricultural runoff and pollution, but is predominantly the result of increased water temperatures.

There are few ecosystems on Earth more vulnerable to climate change than the coral reef, which only grows at a rate of less than an inch a year. Coral requires a delicate balance of minerals in the water and a temperature that does not vary more than a few degrees at any time.

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Malaysia is famous for its reefs, and they act as a huge tourist pull, leading the department to issue a warning that "If bleaching is greater than 80%, further management interventions may include temporary access restrictions to protect affected reefs."

Tour operators were also urged to only take a controlled number of tourists on trips to the reefs to reduce pollution, fishing, and the potential of damage being done to the coral.

Coral reefs worldwide are under threat from similar mass bleaching events as ocean temperatures rise and human activity fills the water with pollutants.

In July last year, scientists warned that the Florida Keys was running the risk of "having massive fish die offs" and "sea turtle die offs." The situation is so bad that scientists are cutting off bits of coral and putting them into cooler land-based water tanks.

Australia's Great Barrier Reef has also faced its fair share of adversity. As ocean acidification and severe agricultural runoff combine with warming waters, mass bleaching events have started to occur every few years.

In April, the National Oceanic and Atmospheric Administration (NOAA) announced yet another bleaching event. This time, however, it was a worldwide event that threatened the total collapse of global coral reef ecosystems.

"As the world's oceans continue to warm, coral bleaching is becoming more frequent and severe," NOAA's Coral Reef Watch coordinator Derek Manzello said in a statement.

"When these events are sufficiently severe or prolonged, they can cause coral mortality, which hurts the people who depend on the coral reefs for their livelihoods."