Rotting Whale Carcasses Are Bringing Risk of Shark Swarms to Australian Coast
The government of Western Australia revealed that a historic number of dead whales littered its beaches this year.
Image: Flickr/Elias Levy
More and more dead whales are washing up on the shores of Western Australia, luring swarms of hungry sharks to popular beaches.
At least 44 whale carcasses were reported on or near the coastline this year, the state’s Department of Biodiversity and Conservation told The West Australian on Monday.
That represents more than half of the 85 carcasses found over the past eight years, and excludes the 150 pilot whales that beached themselves in Western Australia’s Hamelin Bay in March for unknown reasons. The state expects the number of dead whales to keep growing.
In May, authorities scrambled to remove a putrefying 75-foot-long fin whale that left an “oil slick” of remains on a beach in Albany.
A dead pilot whale calf on Swanbourne Beach last month prompted the Department of Primary Industries and Regional Development to warn: “While it’s not uncommon for sharks to be present off the Western Australian coast throughout the year, people should exercise additional caution until the whale carcass is removed.”
And according to Sharksmart, a website launched by the Western Australia government that provides real-time shark updates, a whale carcass currently near Yallingup “may continue to act as an attractant to sharks.”
Western Australia researchers have tagged 542 resident sharks, including 297 great whites, as part of a government program to increase awareness about the ocean predators. Sharks outfitted with acoustic tags ping a network of satellite receivers, allowing authorities to monitor their whereabouts.
The state’s relationship with sharks has been a tumultuous one. More than a dozen shark related deaths since 2012 bolstered a controversial movement that aimed to trap and kill those deemed an “imminent threat.” These methods were opposed by conservationists and eventually canned for lacking sufficient evidence.
As for the historic rise in whale deaths, the state seems unworried, even attributing it to good news.
“The humpback whale population recovery along the WA coastline is one of the strongest in the world for this species and it is likely that the numbers of whales migrating up the coast has increased in recent years,” said the Department of Biodiversity and Conservation.
Indeed, humpbacks near Western Australia have rebounded to 90 percent of their pre-whaling numbers—a record-setting comeback for the species, according to a 2015 survey by Australian researchers.
The agency said this year’s deaths were due to “natural attrition” and that it’s reasonable to expect mortality to be proportionate to population size.
However, other whale deaths, such as the mass stranding of 150 pilot whales in Hamelin Bay, are more mysterious. Scientists speculated at the time that “illness, navigation errors, and human interference” may have been to blame.