Tasmania's Pilot Whales Injured by Undersea Earthquake


Fifty-three out of sixty-four pilot whales died on 20 November when their pod stranded on Anthony’s Beach near the town of Stanley on Australia’s island state of Tasmania. Eleven whales were moved to a deep water area and released back into the sea. Officials attached satellite tracking devices to 5 of the 11 and they moved off to the east in the eastward flowing counter current.

“Not only have they survived being put back in the water after their traumatic ordeal but they’ve also found each other and are traveling with each other,” the Department of Primary Industries and Water’s David Pemberton said. He said the tracking devices had proven that the rescue efforts, which involved swooping huge nets around the beached animals and hauling them on to vehicles and then releasing them at another beach, had been successful. “For the first time in Australia, we have now got data which tells us that they are doing okay — it is fantastic and incredibly exciting,” Pemberton told national news agency AFP.

The Deafwhale Society is doubtful that these 11 animals are safe and sound. The whales are moving with the current that normally flows from west to east in the Bass Strait. We predict two outcomes: (1) The earthquake-injured whales will end up in the bellies of hungry sharks, and (2) if the sharks don’t culled them, there is a good chance they will strand again somewhere near Flinder’s or Cape Barren Islands. If they get passed the shallow water between Flinder’s and Cape Barren, they will likely be washed out into the Tasman Sea.

The SEAQUAKE SOLUTION (http://deafwhale.com) developed by the Deafwhale Society indicates that most whale mass strandings are caused by undersea earthquakes. More specifically, the stranding on 20 November 2008 on Anthony’s Beach near Stanley was caused by the event listed below:

Source: US Geological Service
 FILE CREATED: Sun Nov 23 05:21:55 2008
 Circle Search Earthquakes= 1
 Circle Center Point Latitude: 45.000S Longitude: 100.000E
 Radius: 1000.000 km
 Catalog Used: PDE
 Data Selection: Preliminary Data Only

PDE-Q 2008 10 25   223507.93 45.22S  97.05E 10 km 5.1 mbGS

Local time at the epicenter was 6:35 am on 26 October 2008. The depth of focus of the 5.1 magnitude earthquake was restrained by the computer at less than 10 km.

In general, the seafloor danced rapidly during the earthquake, pushing and pulling at the water in a fashion to generate excessive changes in the hydrostatic pressure surrounding the area where the pod of pilot whales were feeding. The quick fluctuations in pressure caused the volume of air inside the head sinuses of the whales to increase and decrease rapidly in response to the changing pressure resulting in a barotraumatic injury in the membranes that surround these sinuses.

The whales use these sinuses to generate echonavigation signals and to read the returning echo, thus an injury of this nature would not only disrupt diving and feeding but also disable echonavigation. A pod of earthquake-injured pilot whales would surface but not be able to dive again, nor be able to generate or determine direction of their navigating signals.

The vibration from the earthquake would be like a dinner bell to any nearby sharks.

The pod would huddle together to fight off shark attack. The sharks would take the most seriously injured. The rest would stay huddled swimming off in an unknown direction in an attempt to move away from the sharks.

Any swimming action by the pod would turn their streamline bodies downstream in the path of least resistance. Surface currents from the epicenter, known as the Antarctic Circumpolar Current, flow from the west to the east and would direct the wounded pod from the epicenter toward the southern tip of Tasmania (see chart below).

The distance from the epicenter to Anthony’s Beach near Stanley is about 2,500 miles. Assuming the whales swam along at 3 knots in a 3 knot current, they would travel roughly 150 knots per day. Of course, there would times when the whales went off in different direction to escape the sharks so a good estimate on distance travel every day might be 100 nautical miles. The earthquake occurred on 26 October and the stranding occurred on 20 November so the time line fits perfectly.

The material in this press release comes from the originating research organization. Content may be edited for style and length. Want more? Sign up for our daily email.

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