{"id":294695,"date":"2026-02-21T05:59:10","date_gmt":"2026-02-21T05:59:10","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/294695\/"},"modified":"2026-02-21T05:59:10","modified_gmt":"2026-02-21T05:59:10","slug":"new-study-debunks-theory-on-why-sharks-fled-aussie-islands-after-vicious-orca-attack","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/294695\/","title":{"rendered":"New study debunks theory on why sharks fled Aussie islands after vicious orca attack"},"content":{"rendered":"

A\ufefffter six orcas were filmed viciously killing a great white shark off South Australia<\/a>‘s Neptune Islands in 2015, sharks<\/a> disappeared from the waters for over two months.Their abnormally long absence was attributed to the incident, as a study in South Africa<\/a> suggested similar instances along their coast caused sharks to abandon their habitat. \ufeff<\/p>\n

But now, new 12-year research in Australia \ufeffhas debunked that theory.<\/p>\n

\"SixSix orcas were filmed viciously killing a great white shark off South Australia’s Neptune Islands in 2015. (Adventure Bay Charters\/YouTube)<\/p>\n

Dr Isabella Reeves, a postdoctoral researcher from Flinders University, led the study and said her team identified six instances when sharks left the Neptune Islands for weeks at a time.<\/p>\n

“These were more than 42 days, and only one of them had this killer whale predation, which was the event we had in 2015,” she said. \ufeff<\/p>\n

The encounter that started it all<\/p>\n

A cage diving company based in Port Lincoln took a group out to get up close with sharks at the Neptune Islands on February 2, 2015.<\/p>\n

But just 20 metres from their vessel, they witnessed six orcas going in for the kill.<\/p>\n

Three orcas appeared to \ufefffence in a shark, while the others rammed it with their heads.<\/p>\n

They pushed the shark underwater and an oil slick appeared on the surface, indicating the liver had been consumed.<\/p>\n

The footage of the encounter went viral and gained national interest.<\/p>\n

Reeves said it was considered very rare at the time but has been recorded more over the years, particularly in Australia, South Africa, California and Mexico. \ufeff<\/p>\n

“The fact that killer whales had rocked up to the Neptunes, which is a really small island group that’s offshore, and someone was there to actually document it, it was a really rare opportunity to try to dissect the situation more once we had gotten more data over the years,” she said.<\/p>\n

\"NewResearchers spent 12 years monitoring shark behaviour. (Supplied)<\/p>\n

Sharks disappear from Neptune Islands<\/p>\n

Sharks disappeared from the waters in the Neptune Islands for the next 69 days after the orca attack.<\/p>\n

Andrew Fox from Rodney Fox Shark Expeditions said he saw an increase in sharks at the Neptunes from the early 2000s, but that changed in 2015.<\/p>\n

“It’s been very much more patchy since then, and in the last two years, it’s been really slow,” he said. \ufeff<\/p>\n

“It seems like there’s a lot more than there is, but I’m worried that there has been a bit of a slow decline, and we’re certainly seeing a lot less in the last two years than we’ve ever seen.\ufeff”<\/p>\n

There have also been environmental changes in recent years, including record oceanic upwellings and a toxic algal bloom. \ufeff<\/p>\n

Fox has only seen orcas at the Neptune Islands a handful of times in his 50 years in the business.<\/p>\n

“We had a really big Orca, a big male with an extremely tall dorsal fin, come up to the back of our vessel and smash its tail up and down repetitively and scare away a big white shark we knew, a formidable, five-metre male we know as Dragon,” he said.<\/p>\n

“We haven’t seen Dragon since, so I’m a bit worried about what happened to him. But other white sharks did come back a week and a half or 10 days later.”<\/p>\n

\"NewDr Isabella Reeves led the study. (Supplied)<\/p>\n

\ufeffTwelve years of research<\/p>\n

The research team used acoustic telemetry data, based on listening stations that ping once a tagged shark is near, \ufeffand sightings from tourism companies to track sharks over 12 years to understand whether the 2015 absence was exceptional or behavioural.<\/p>\n

They identified six instances of prolonged absences, including a brief five-day departure during an orca sighting in October 2024 and a four-day absence during the death of a tagged whale.<\/p>\n

But they \ufefffound that not every orca encounter or shark death led to these absences.<\/p>\n

Reeves said movement patterns of great white sharks in the Neptune Islands were highly variable. \ufeff<\/p>\n

\ufeff”There’s definitely long gaps in their presence, which can happen with or without killer whale activity,” she said.<\/p>\n

“It’s really hard to say. There’s so much going on in our oceans right now, which could be contributing to this.<\/p>\n

“But I think the main takeaway is that it’s not the killer whales at the Neptunes that are causing the prolonged absences.”<\/p>\n

Another study is currently under way to understand what causes prolonged shark absences.<\/p>\n

NEVER MISS A STORY: Get your breaking news and exclusive stories first by following us across all platforms.<\/p>\n","protected":false},"excerpt":{"rendered":"A\ufefffter six orcas were filmed viciously killing a great white shark off South Australia‘s Neptune Islands in 2015,…\n","protected":false},"author":2,"featured_media":294696,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[111,139,69,147,406],"class_list":["post-294695","post","type-post","status-publish","format-standard","has-post-thumbnail","category-wildlife","tag-new-zealand","tag-newzealand","tag-nz","tag-science","tag-wildlife"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/294695","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=294695"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/294695\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/294696"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=294695"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=294695"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=294695"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}