Divers clutch wooden spears as they plunge beneath the waves, hunting hordes of hungry starfish destroying the coral reefs around the Cook Islands.<\/p>\n
These makeshift tools are their best weapons in the war against crown-of-thorns starfish, a coral-munching species eating through tropical reefs already weakened by climate change.<\/p>\n
The Cook Islands, a South Pacific nation of about 17,000 people, is in the grips of a years-long outbreak, says marine biologist Teina Rongo.<\/p>\n
“It can completely kill off the entire reef, right around the island,” said Rongo, who organises volunteers protecting the reefs fringing the isle of Rarotonga.<\/p>\n
“I think there seems to be a Pacific-wide outbreak at the moment, because we’re hearing other countries are facing similar challenges.”<\/p>\n
A single crown-of-thorns adult can eat more than 10 square metres (110 square feet) of reef each year, squeezing its stomach through its mouth to coat coral in digestive juices.<\/p>\n
They pose a major threat to Australia’s Great Barrier Reef, where scientists have developed robots that hunt down the prickly invertebrates and inject them with poison.<\/p>\n
“At the moment, you basically kill them by injection,”\u00a0said researcher Sven Uthicke, from the Australian Institute of Marine Science.<\/p>\n
“It could be vinegar, it could be lime juice or ox bile.<\/p>\n
“Others are building chemical attraction traps. It’s all very promising — but it’s in the development stage.”<\/p>\n
Rongo finds it quickest to pry the feasting starfish loose using a wooden stick cut from the dense timber of the Pacific Ironwood tree.<\/p>\n
“Basically, we use a stick with a hook at the end,” he said.<\/p>\n
“We’ve made some modifications over time because we were getting pricked by these starfish. It’s painful.”<\/p>\n
Named for their hundreds of venomous spikes, crown-of-thorns starfish\u00a0have as many as 21 fleshy arms and can grow larger than a car tyre.<\/p>\n
They are typically found in such low numbers that they are not considered a problem.<\/p>\n
But sporadically populations explode in a feeding frenzy that rapidly strips the life from reefs.<\/p>\n
– ‘Plague proportions ‘ –<\/p>\n
They spawn in “plague proportions”, according to the Australian Institute of Marine Science, and are a major driver of coral loss.<\/p>\n
From the Red Sea to the Pacific Ocean, crown-of-thorns outbreaks appear to be becoming both more frequent and more severe.<\/p>\n
“Some argue that the crown-of-thorns has become chronic in the last few decades,” said Rongo, talking about the reefs of the South Pacific.<\/p>\n
Scientists suspect these outbreaks are triggered by a mix of factors, including nutrients leached into the sea from agriculture and fluctuations in natural predators.<\/p>\n
But the damage they can cause is getting worse as reefs are weakened by climate change-fuelled coral bleaching and ocean acidification.<\/p>\n
“This is why it’s important for us to help the reef,” says Rongo. <\/p>\n
Scuba divers scour the Cook Islands’ reefs for hard-to-spot starfish wedged into dimly lit crevices.<\/p>\n
Once peeled off the coral, the starfish are pierced with a thick rope so they can be dragged back up to a waiting boat.<\/p>\n
The day’s haul is dumped into a plastic chest before the starfish are lugged ashore to be counted, measured and mulched for garden fertiliser.<\/p>\n
They are known as “taramea” in Cook Islands Maori, which loosely translates to “spiky thing”.<\/p>\n
The volunteer divers working with Rongo and his environmental group Korero O Te Orau — or Knowledge of the Land, Sky and Sea — remove thousands of starfish every year.<\/p>\n
Rongo is spurred by the devastation from the nation’s last major infestation in the 1990s.<\/p>\n
“I was part of that eradication effort.<\/p>\n
“We were too late when we did decide to do something about it. It went on and ended up killing the reef.”<\/p>\n
sft\/lb\/tym<\/p>\n","protected":false},"excerpt":{"rendered":"Divers clutch wooden spears as they plunge beneath the waves, hunting hordes of hungry starfish destroying the coral…\n","protected":false},"author":2,"featured_media":17968,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[64,63,19310,19307,19308,137,19309,19311],"class_list":["post-17967","post","type-post","status-publish","format-standard","has-post-thumbnail","category-health","tag-au","tag-australia","tag-australian-institute-of-marine-science","tag-cook-islands","tag-crown-of-thorns-starfish","tag-health","tag-teina-rongo","tag-tropical-reefs"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/17967","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=17967"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/17967\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/17968"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=17967"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=17967"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=17967"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}