seaquake theory explains why whales mass strand

Any sudden change between the surrounding (ambient) water pressure and the air pressure inside enclosed air spaces of a diving mammal will result is trapped air expanding or contracting too rapidly resulting in a barotramatic injury to the tissues enclosing the air spaces. This is especially so in and around the middle ear and sinus cavities where an imbalance in pressure could result in a ruptured eardrum or a bleeding sinus. (link to barotrauma)

Marine mammals, in the same fashion as scuba divers, prevent barotrauma by descending and ascending at the proper speed while at the same time doing everything they can to equalize the ambient water pressure with the air pressure inside their bodies. Diving is a relatively safe sport as long as the diver does not encounter any sudden and drastic changes in pressure. The same is true for whales. As long as the changes in ambient water pressure come gradually in pace with the whales' ability to compensate, all is well; however, if the changes come too rapidly or too drastically, then barotraumatic injury will result.

There are two ways to demonstrate the validity of this theory. The first method involves using the seaquake data file coupled with oceanic currents to predict strandings 30 days in advance (see abstract above). The second method involves examining an actually stranding to see if the facts support the theory in a process known as scientific modeling.

Herein we model the mass stranding of 129 pilot whales that beached on 20 December 2005 on Puponga Beach inside Golden Bay, New Zealand. (link)

In addition to the 129 whales, ten days later, on New Year's Eve, 49 more pilot whales died after becoming stranded near the tip of Farewell Spit. Eight died naturally, while 41 others were shot because it was considered too dangerous to attempt their rescue (link). On 16 January 2006 another pod of 5 pilot whales beached near Puponga Bay on the same stretch of Golden Bay that was the site of a mass stranding before Christmas (link). (The Seaquake Theory suggest that the 183 whales in these three strandings likely came from the same pod and were injured by the same seaquake.)

The pod was injured several months prior to the stranding. Their travel path from the site of their injury would be determined by oceanic currents (current determines the final stranding site). Thus, if this theory is correct, to find the most likely seaquake one needs to trace back upstream about 65 days to a known habitat for the species in question and start checking the earthquake data file for a suspicious event.

Based on what we know now, the most likely event will be the largest you can find with a shallow focal point that occurred during the early evening hours when the whales were more likely to be on a feeding dive. Another factor that shows up a lot is events followed closely by aftershocks. (It could be that the first event causes a slight injury that sets the whales up for a more serious injury during the aftershock?

Thus, for a stranding event in New Zealand of a cold-water species like the long-finned pilot whales we need to look west somewhere upstream in the West Wind Current. Since the stranding occurred on 20 December, the most likely time for the seaquake will be around 15 October.

Our experience over the last 30 years indicates that the whales can travel from 2,000 to 4,000 miles down stream within the time it takes for them to lose the ability to avoid a beach. We can assume that they occasionally catch a meal from time to time but generally are highly stressed and slowing deteriorating. Experience has also taught us that whales seems to cover a lot more distance in the fast moving Circumpolar Current than they do in the Northern Hemisphere.

Thus, we checked the earthquake data base at ANSS Catalog Search with the following parameters:

The time used for the above events are UTC (+8 hours in front of W. Australia Standard Time). Thus, we must subtract 8 hours to find local time.

Rarely does a potent shallow-focused seaquake stand out as much as the magnitude 6.5 (only 8 km deep) on the night of 28 October during prime evening feeding time. The quake was recorded by 416 seismographic stations (Nst) around the world and followed by several potent aftershocks. The aftershocks may have added insult to injury. This quake could have even injured several different pods so we should not be surprised if many strandings occur downstream in and around New Zealand from 15 December 2005 thru 15 February 2006.

The importance of the shallow hypocenter at only 8 km below the seafloor should also be stressed here. The center of focus of an earthquake is the point of origin of the disturbance. The pressure waves (P-waves) move out from this point generally in a circular pattern so that the closer the point of origin is to the water interface, the less the overall area of the epicenter and the greater is the disturbance that enters the water. This point is critical in picking the most suspicious events and might even be more important than magnitude.

The magnitude scale is logarithmic, thus a magnitude 6.5 quake is 15 times more powerful than a magnitude 5 seaquake and 150 times more powerful than a magnitude 4 event. However, if a magnitude 6.5 quake was focused 100 km below the seafloor, then a magnitude 4 event at only 4 km deep might be far more dangerous to a pod of diving whales.

Then there is the question of the speed of the vertical movement in the seafloor. The point is that picking any particular event over another event is complicated and will require much more research.

We also know that many seaquakes occur within the upper 3-4 kilometers of the seabed but these shallow depths rarely appear in the earthquake records because the seismologists reading the seismographs often just report the events as 10 km or under. In other words, for most seaquakes the depth will be reported as under 10 km even if the hypocenter was only 5 km deep. Thus, whether a magnitude 3.5 seaquake at 3 km deep is more dangerous to a pod of whales verses a magnitude 5 seaquake at 10 km deep is guess work. In other words, it is far from clear that the 6.5 seaquake at 8 km deep was indeed responsible although it appears as highly probably.

If so, then the pod traveled roughly 3,750 miles over a period of 52 days or 72 miles per day (~3 miles per hour). However, their travel path was likely here and there and not in a straight line. Best guess is that the pod swim downstream ~150 miles per day (6 miles an hour) inside a current traveling at ~3 miles per hour. The pod could have also spent a week or so inside a current Eddie going around in circles.

Since their food is also the primary source of their fresh water, any pressure-related injury preventing the pod from diving would quickly lead to dehydration as well as malnutrition. Sharks would also move in for the kill. How long a pod could survive under such circumstance has never been answered. We know whales are better than camels at conserving fresh water. We also know they can drink small amounts of salt water. We can only guess that they might be able to survive for three-four months if they caught an occasional meal on the surface.

The stress of such an event, coupled with dehydration and malnutrition, would also weaken the immune response of each whale and allow their normal burden of parasitic worms to superinfect, especially in and around the traumatized sinus cavities (parasites and stranded whales) and other internal injuries. The barotraumatic breaks in the sinus membranes would allow these worms to crawl into normally protected areas such as the large acoustic nerve situated just behind the sinus cavities and eventually into the brain. Auditory misdirection and the failure of localization, either from the initial trauma or from the parasitic assault on the acoustic nerve, is probable.

Pelagic toothed whales store fat for energy reserve between their internal organs. They would not exhibit outward signs of starvation because the layer of blubber surrounding their body is not digested in a crisis. This fat is for thermal protection and not for store of energy. If starving whales could easily digest their blubber, they would quickly die from cold exposure.

Such an injury would vary with the intensity of the pressure and length of time of exposure. Some pods might return to the surface with only ear/sinus pain and recover if they found food on the surface to sustain them during an unknown recovery period. Whereas the most seriously injured pods might return to the surface bleeding from their ears and in great pain, thrashing about from their injuries attracting oceanic sharks to their condition.

Those killed during the seaquake would sink to the bottom. The most-seriously wounded would be taken by the sharks or by killer whales. The least injured would recover if they found ample food on the surface to sustain them during the recovery period.

Thus, only those pods unable to find enough food on the surface to enable recovery would survive long enough to reach a beach and strand.

The pod's major struggle would be to find food on the surface before they reached a point of no return where recovery would be unlikely. How long an injured pod might survive before reaching its point of no return is unknown. These pods might be able to survive for many months if they occasionally found a bit of food on the surface.

Oceanic sharks (and killer whales) would chase them like wolves dog caribou, picking off any stragglers. Sharks would also cause the pods to close ranks and remain in a tight group and might even put excessive pressure on the pod and prevent them from taking advantage of a feeding opportunity. The constant threat of being eaten alive might cause the pod to flee from the area of a meal rather then linger around and try to feed. Pods of killer whales might also be attracted to the wounded pods.

At first, the travel path of an injured pod might be erratic as it goes about looking for food on the surface and/or trying to avoid shark and killer whale attack. Being pressured by the sharks combined with not concentrating on where they are or where they are going, the stressed pod eventually gets lost at sea. At this point in time, their travel path becomes solely directed by oceanic currents and trying to escape attack.

CAPE COD STRANDINGS

Mass strandings in Cape Cod were compared to the earthquake data file. It was obvious that the most likely seaquakes occurred about 2600 miles upstream from Cape Cod along the Mid-Atlantic Ridge several hundred miles both south and north of Iceland. This area turned out to be the nearest upstream seismic hot spot that was also known to be the home range for all the species that mass stranded on the Cape.

Cape Cod has recently been receiving an increase in strandings of smaller pods. This trend is more likely due to the overall reduction in the numbers of sharks. Smaller pods would have less ability to defend against sharks so smaller pod strandings in the past were unlikely; however, with less sharks, more and more smaller pods survive long enough to strand. (specific comments of strandings in Cape Cod Bay).

Cape Cod Bay looks similar to New Zealand's Golden Bay. These areas are both situated about 65 days travel time downstream from a known habitat of the species in question. They both receive repeated strandings year after year during the same three-month period (November, December, and January) corresponding with the squid breeding season. The exact areas where the pods beach all feature accreting sand indicating a current inflow. They also feature a geographic catching arm system extending out to sea that tends to trap the injured pods moving with the flow.

Whales do not strand in a heavy sea because breaking waves create currents running along shore and rip currents running offshore. These currents would direct whales away from the beach, not toward it. These currents would also tend to free stranded whales.

The time it takes the pod to reach the point where it can no longer avoid a stranding also depends on whether the pod was lucky enough to find a bit of food on the surface. Whales can't drink salt water any more than man; all their fresh water comes from their diet. Thus, one of the most prevailing medical conditions to be expected in stranded pods is dehydration following closely by malnutrition and vitamin depletion.

This researcher compared the earthquake data file with the stranding file. After studying hundreds of mass strandings and comparing thousands of seaquakes, a credible pattern emerged. Each stranding usually has an average of six potential seaquakes that might be responsible. The most likely events occur after sundown, which compares favorably with the time when the whales begin their daily feeding dives. These seaquakes occur on average 65 days travel time upstream from the stranding site. The actual distance can vary from 1,000 to 3,500 miles depending on the speed of the oceanic current. If the current is swift, as it is upstream from New Zealand (comments on recent strandings in New Zealand), the injured pods will naturally travel further or arrive at the beach in better condition than they would in Cape Cod where the currents are slower.

The first visitors to the beach each morning are the ones who report sixty percent of the strandings indicating that the pods most often strand at night when their vision is less likely to help them stay out of shallow water. Another thirty percent of the non-navigating pods are drawn into bays and coves with the current during a rising tide. These pods are often observed to be then milling around the bay/cove at high tide and then become stranded when the tide recedes.

Current, the same force that delivers each grain of sand to the beach, is also the same force that selects the final stranding site. Local weather increases strandings if the general wind direction sets the surface currents shoreward. If the wind sets the surface currents offshore, then local weather conditions will usually prevent a stranding since they alter the shoreward flow.

Rescued whales will likely re-strand again if released against the inflow of the current. If released with the outflow, they will move off and give the appearance of rescue only to re-strand many miles downstream or end their lives in the bellies of sharks. When rescued pods re-strand, they ALWAYS do so downstream from the site of rescue, never upstream.

Whales have evolved for 50 million years in seismically active waters. They must have made evolutionary changes to this fact (evolutionary adaptation to seaquakes).

Younger animals, unable to dive to the deeper depths due to reduced lung capacity, may have avoided injury, but remained with the pod due to the close-net nature of pelagic whales. It has also been reported that these young are left in the care of several adult female babysitters. Nursing young and their babysitters, when stranded on a beach, would naturally present in better condition. If this is true, then there might be one or two animals amongst the stranded pod that is not injured and will thus have the best chance of surviving. Rescuers should concentrate their efforts to find these animals.

Coastal species would also be vulnerable to barotrauma from earthquakes, but do not mass strand because of the social looseness of their pods and their familiarity with near shore waters.

Whales use sonar to echolocate their position in relation to known features on the seafloor in the same way man uses vision to recognize his location on land. The sonar signal must be relatively powerful in order to reach the bottom and return a useable echo. A good guess would be that a whale would likely need to generate a signal at about 220 dB re 1 micro Pa to bounce off the bottom in one thousand meters of water. Water supports compression, not tension (vacuum). If the negative phase of the echo-navigating signal exceeds four to five psi of vacuum at the surface, bubbles will form in the water (cavitation) and the signal will fail. Since 220 dB equates to about 15 pounds per square inch, the whale needs to dive below about 10 meters to take advantage of increased pressure before he can generate a loud navigation signal. Thus, a barotramatically injured whale unable to dive to 10 meters would also be unable to use sound to navigate in deep water.

The use of navigational sonar also requires the whales to dive below the upper layers of the surface to escape interference from bubbles entrained by breaking waves. The diving injury might prevent this shallow dive since the greatest percentage of pressure changes would be encountered in the upper ten meters of the sea. There is also a strong possibility that the hypothetical injury might disrupt their use of sonar in some other fashion. Thus, the odds are increased that our injured pod would lose their bearings. Without a sense of direction, the pod would naturally be turned by the flow of the current and pointed downstream. If the pod huddled together and swam along in a tight group at estimated speed of ~two knots inside a ~two knot current, they would travel downstream ~100 nautical miles per day (185 km/day). Assuming again that they would survive for 45 days, the pod could be expected to travel downstream from the site of their injury ~4,500 nautical miles (~8,325 km). However, "downstream" does not mean distance traveled in a straight line since the current meanders in all sorts of directions and sometimes spins in circles (eddies) for days.

Thus, the answer to the question of where we might find injured pods depends on how much time expired since the injury. If we are asking where we might find them on the day of the injury, then the answer is where ever their favorite food (squid) might be found. Squid like to hang out around mid-oceanic ridge systems during their three-month breeding season. They then move off the ridges and travel to other areas near large seamounts and other such underwater features.

We might also expect that oceanic sharks would dog our injured pod in a similar fashion as wolves dog a herd of caribou. The pod would be steadily push downstream and may even swim along faster than two knots. Those individuals injured the worse would lag behind and be culled by the sharks.

The whales also stand a good chance within a few weeks of being directed into a land mass somewhere along their journey. If so, their reaction might depend on the amount of time since their injury. At first, in a relatively healthy condition and not being familiar with land, we would expect the members of the pod to use all its senses (including excellent night vision) to avoid bumping into land. However, as they were weakened over time, they would become less and less capable of avoiding the beach. Vitamin depletion would weakened their normal excellent night vision increasing the chance of bumping into a beach at night. The beach seems a reasonable guess since current, the same force that built the beach, is also directing the whales. If our pod did strand, we can also expect the site to be located where the beach is building and not where the beach is being washed away. We would also expect that our pod might get trapped by a large land mass that extended out to sea and opposed the flow of the current. Capes that extend a finger of land or a sand bar out for many miles opposing the flow would serve as natural traps for injured whales moving along with the current. Cape Cod in the US, Golden Bay and Hawke Bay in New Zealand and Cape Sorell in Tasmania are excellent examples, and the leading stranding sites around the world.

Thus, the distance traveled by our model would depend on the extent of the initial injury, the current encounter along the journey and the presentation of any land masses. Other major factors that would play a part in driving the pods ashore would be the presence of sharks and the increase in the speed of the inflowing current during a rising tide, especially through narrow inlets leading into harbors and backwaters. The best example here would be Macquarie Harbour on Tasmania's western shore. The current here on a rising tide would sweep any pod that nears the mouth of the inlet into the Harbour where it would be sure to beach.

We must also consider that our injury pod might be separated by a major storm at sea and form back together in two or three smaller pods. Thus, a dozen whales might be carried into the beach at one location while others from the same pod strand somewhere else nearby.

Drive fisheries for pilot whales and dolphins originated in areas downstream from seismically-active heavily populated habitat of the species being hunted. (click here to read more on drive fisheries and seaquake-injured whales)

Captain David Williams