Scientists Say Killing Rats Could Save the Reefs


In a race to save one of the world’s most beautiful and complex ecosystems, scientists are looking for ways to approach this issue. Until now, the obvious culprits that killed the coral reefs were warming waters and pollution.

But tropical islands harbor a threat too: RATS!

Scientists found that rats threaten the survival of reefs too. You might not see the link between them, but Prof. Nick Graham from Lancaster University explains in his paper which he published in the journal Nature the following:

“Coral reef systems are at crisis point because of climate change. And we’re desperately trying to find ways to enhance the resilience of coral reefs and allow them to cope with climate change.”

The study explains that rats kill eggs and babies of the seabirds, disrupting the ecosystem by diminishing the number of birds. The droppings from those birds fertilize the reefs around the island.

“The islands with no rats are full of birds, they’re noisy, the sky is full and they smell – because the guano the birds are depositing back on the island is very pungent. If you step onto an island with rats, there’s next to no seabirds.”

The islands with no rats include frigatebirds, noddies, shearwaters, boobies, and terns which travel to the ocean for hundreds of kilometers to find food. As they return to the island, their droppings contain nutrients from fish, said Prof. Graham:

“These nutrients are leaching out onto the reef.”

With his team, Prof. Graham tracked the source of those nutrients to the fish that seabirds ate. The group of researchers analyzed the algae and sponges on the reef, finding those nutrients there:

“We also found that fish on the reefs adjacent to islands with seabirds were growing faster and were larger for their age than the fish on reefs next to rat-infested islands.”

Near rat-free islands, there were more fish compared to the ones infested with rats.

According to Prof. Graham and his colleagues, a way to help protect coral reef is to eradicate rats. Thus, he said that it “will lead to increased numbers of seabirds and this will bolster the coral reef.”


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