In Australia’s biggest mass stranding, almost 500 pilot whales were found stranded near the remote west coast town of Strahan on the island state of Tasmania. 380 out of 500 whales have died and around 70 have survived. The death toll is expected to increase as the window for rescue now begins to close.
In Australia’s biggest whales stranding, a crew of around 60 conservationists and skilled volunteers have spent days paddling in the cold waters of the Macquarie Harbour. They were surrounded by the anguished cries of the slowly dying whales.
What does Mass Stranding mean?
‘Stranding’ refers to an aquatic animal noticed in a place unusual to its natural habitat. For example, an offshore species found inshore. Oftentimes, stranded animals are found on a beach or in shallow water. Animals that swim in collective groups, such as small cetaceans like pilot whales. They are the most common species that are found stranded.
When three or more animals strand together at the same time and place, it is called ‘Mass Stranding’. It is not necessary for a mass stranding to be confined to only one species at a time.
Some of the identified causes of stranding include diseases, parasite infestation, pollution exposure, extreme weather events, starvation, ship strike and tidal changes. Yet determining the exact cause of stranding of a marine animal or its death is often very difficult.
There is an indefinite need for more research into the understanding of why a relationship in time and location may exist between cetacean mass stranding.
Australia’s largest whales stranding; what happened?
In Tasmania, Australia, a 500 member pod of whales was found stranded along the coastline. The pod was first discovered during an aerial reconnaissance of Macquarie Harbour on September 21, 2020. After two days of a very difficult rescue attempt, the state marine scientists confirmed the death rate of the whales to be 380.
Talking to the Australian Press, Tasmania Arks and Wildlife Service Manager, Nic Deka stated, “From the air, they didn’t look to be in a condition that would warrant rescue,” He added, “Further assessment of their condition would be made by boat and crews would be sent if the whales could be saved.”
This is the biggest mass stranding in the country’s modern history. Tasmania is the only part of Australia prone to mass stranding. Tasmania has had another incident of mass stranding back in 1935 when 294 whales were stranded in the northwestern coast.
Before this year, Australia witnessed a mass stranding of 320 pilot whales near Western Australia state town of Dunsborough in 1996.
70 of those 500 whales were released in the waters, to go back to their families after being healed. Marine Conservation Program & Wildlife Biologist, Kris Carlyon confirmed the successful getting away of those 70 whales. The whales released in the water were marked, to indicate their return.
Kris Carlyon said that some of the whales which were released to the ocean on Tuesday, were stranded again, but those who were redirected by rescuers on Wednesday did not return.
The reason as to why a pod of almost 500 whales were stranded is yet to be confirmed by the authorities. Although, some theories suggest that this happened because the pod accidentally followed sick whales or made a navigational error.
Whales stranding in the world so far
Mass stranding is an issue affecting the marine life tremendously. In the United States of America alone, about 1,000 cetaceans and 2,500 pinnipeds strand annually. Animals that strand alive are cured and returned to the sea safely, and other die and their carcasses are dumped in the sea.
Scientists sometimes have to conduct an autopsy on the dead body of the animal, to determine the cause of stranding. Scientists usually have little to no information about the animal’s history or the circumstances that the animal went through before stranding. Therefore, the cause of death is able to be identified in only about half of the stranded animals.
There are many theories stating that the military sonar exercises contribute to mass strandings of beaked whales. Although it is not yet clear if it is just the sonar sounds or other military exercises like multiple ship maneuvers.
136 mass stranding incidents of beaked whales were recorded between 1874 to 2004. All the 136 incidents had three consistent features. Firstly, the stranding locations were less than 80 kilometres from the 1,000-metre depth contour. Secondly, they occurred in areas where deep water mass strandings had previously been reported. Lastly, all included Cuvier’s beaked whales, a species that does not commonly mass strand.
There have been five major incidents of a mass stranding of whales before these, Greece 1996, Bahamas 2000, Madeira 2000, Canary Islands 2002 and Canary Islands 2004.
But the mass standing in Australia this year precedes all the mass strandings that have happened before.
BBC in its report states five major causes of mass stranding across the world, including sickness and injury, navigational mistakes, following the leader and warming waters.