CHINA WHALE STRANDING
At 9:09 pm on 04 February 2012, four sperm whales were on a deep dive feeding on squid along the drop-off edge of the Philippine Trench offshore of Samar in the Philippine Islands . Suddenly, a shallow focused 5.7 magnitude quake erupted below them. The dancing seafloor filled the water all around them with a series of rapid and excessive oscillations in diving pressures.
This happens every time the seafloor jumps up and down. The jerking movement just naturally generated a series of pressure pulsations in the water. The water pressure bounced back and forth about 4 times every second from 600 pounds per square inch above to about 600 pounds per square inch below ambient pressure. This represents a 1,200 psi change in total pressure. The event lasts about 30 seconds.
Earthquake pressure waves exceeded the sperm whales’ pressure regulating anatomy causing barosinusitis (barotrauma in the sinuses). This has been ongoing for millions of years!
Since intact and functional air sinuses and air sacs are necessary for the function of their biosonar, the sperm whales instantly lost their sense of direction along with their ability to dive and feed themselves.
THEY ARE IN A PANIC!
Upon reaching the surface, the lost pod huddled close to each other for protection against sharks and starts swimming downstream with the flow of the surface current. They continued to swim downstream for 39 days. The current finally guides them into a beach in the Yellow Sea. The sand trapped them near the town of Touzeng in Jiangsu Province (34.351N by 120.174E) during the night of 15 March. The crew of a passing boat saw them the next morning.
Sperm whales feed often on the giant squid along the drop-off edge of the Philippines Trench. They usually dive to ~1000 ft several times every night when the giant squid migrate toward the surface. They rest during the day.
Sperm whales are never seen in the Yellow Sea so the first question is: What were they doing near a beach in this area at 5 o’clock in the morning?
The answer, as stated above, is that the seismic waves had caused an injury that destroyed their sense of direction. In other words, the whales suffered barosinusitis in the air spaces of their heads as a result of an encounter with potent and rapid pressure changes generated by an undersea earthquake.
To see a map of the seaquake area, go to this webpage and click on “Interactive Map.”) You can tell by the design of the black and white beach balls in the chart below that this event was a thrusting earthquake with mostly vertical motion.
The fluctuating seismic pressures in the water around the whales during the seaquake caused the air in their sinuses to expand and contract excessively, resulting in a sinus injury in the nasal complex of the animals large head.
The nasal complex includes the spermaceti organ, the junk bodies, and other associated organs. The primary function of the spermaceti organ and the associated organs in the nose of the sperm whales is to fine-tune the world’s most powerful natural sonar system (link) that the whales use to navigate and find their food.
When rapid and excessive pressure changes given off by a potent undersea earthquake surprises the diving whales, the quick changes in pressure disables their biosonar and they become lost and unable to find their way in the sea.
Barotrauma in the sinuses not only destroys their ability to determine the direction of any returning echoes but also destroys their ability to generate and send the necessary navigating signals.
Due to light absorption by water, most of the ocean is dark beyond a few hundred meters thus limiting visual range. As a result, sperm whales and the other toothed whales (suborder odontoceti) have evolved a system of echolocation as the main way to find food in the darkness of the ocean similar to the navigation system used by bats.
When navigating, the sperm whale emits a focused directional beam of broadband clicks. The forcing of air through a pair of phonic lips at the front end of the nose, just below the blowhole, generates the clicks. The sound then travels backward along the length of the nose through the spermaceti organ. Most of the sound energy is then reflected off the air sacs that sit against the skull and down into the Junk Bodies which focuses the clicks into an acoustic beam. Some of the sounds will reflect back into the spermaceti organ and back towards the front of the whale’s nose where the spermaceti organ reflects it a third time.
This back and forth reflections, taking only a few milliseconds, creates a multi-pulse click structure. This multi-pulse click structure actually allows researchers to measure the size of the whale’s spermaceti organ using only the timing of its clicks. The lower jaw is the primary reception path for the echoes. A continuous fat-filled canal transmits received sounds to the inner ear (link).
THUS, A PRESSURE RELATED INJURY RECEIVED DURING EXPOSURE TO A SEAQUAKE INJURES THE AIR SACS AND SINUSES USED TO REFLECT SOUND IN THE SPERM WHALE’S HEAD AND RENDERS THE ANIMAL UNABLE TO NAVIGATE.
The big question then is which way does a sperm whale swim if it has no sense of direction?
Sorting out which way acoustically blind sperm whales will swim is easy. Close your eyes and start swimming in a current. You will quickly be turned by the resistance to the flow and pointed downstream. Anything and everything without a sense of direction will always swim or float downstream. Downstream is the path of least resistance and the path non-navigating whales and dolphins always take.
North Equatorial Current flows into the east coast of the Philippines in February at Samar. The southward-flowing branch is the Mindanao Current, and the northward flowing branch is the Kuroshio or Black Current. The Kuroshio current guided the injured whales downstream. The flow was north along the east coast of the Philippines until it enters the Luzon Strait. The strait is about 350 km wide and is 2500 m deep at its deepest point.
The Kuroshio usually continues north past the strait to flow along the east coast of Taiwan. (Fig. 1(a) on page 772) Occasionally, the Kuroshio penetrates through the Luzon Strait into the South China Sea, forming a loop current. (Fig. 1(b) on page 772) When this happens, the Kuroshio flows to the west through the Luzon Strait just north of 20N. The water may travel as far west as about 117E before turning north and then east. The flow is apparently following the shelf break southwest of Taiwan. Part of this water may enter the Taiwan Strait. It is generally thought that Kuroshio water occasionally flows north through the eastern side of the Taiwan Strait. (Fig.1(b)) The Kuroshio east of Luzon and Taiwan is ~140 km wide and ~800 m deep.
The Kuroshio carried the injured sperm whales northeast where they eventually washed into the Yellow Sea/ East China Sea. Once inside, the whales guided by the circular flow into the muddy/sandy bottom where they beached themselves and died.
Strong tidal currents, river discharges, air-sea interactions, tidal mixing, and the Kuroshio current direct the flow in the Yellow Sea.
The Yellow River and the Yangtze River surround the basin (link).
Capt. David Williams
Deafwhale Society (the oldest marine mammal conservation group in the world)