The fatal shore
Author - Bruce Montgomery

The Weekend Australian Magazine. May 2-3, 1998

Only a generation ago it was believed whales committed mass suicide, that inexplicably they threw themselves out of the water upon some hidden signal from their leader. How could a mammal that is so close to Man that it engenders a deep, primeval stirring of kinship and empathy within us, behave more like a lemming? Is the whale the cetacean equivalent of a Jonestown or Waco cultism; blind faith in a misguided leader?

Now we know better; but do we know more? Do we understand the forces at work when the biggest animals on Earth become imperilled I and we are left not only with the debris of their death, but the trauma of not knowing if we could have saved them.

The Southern Ocean ought to be a safe haven for whales swimming in the latitudes of the Roaring Forties, below the mainland coast of Australia . There is a huge whale sanctuary here that extends from latitude 40°, south to the Antarctic. It provides the whale with theoretical protection from the world's commercial whaling fleet. That Japan and Norway continue to take whales - in Japan 's case for what are supposed to be scientific reasons - is of continuing frustration to the Inter­national Whaling Organisation, the league of whalers themselves and the world's conservation groups. Yet whales continue to die prematurely en masse in these latitudes, stranded in family groups along iso­lated beaches in South Africa , New Zealand and Australia . That they die of their own accord, appar­ently without any interference from man, led initially to the inference that these mass strandings represent inexplicable suicides, a group misunderstanding that, for the survival of the species, this herd had to die. It now seems certain that they are dying because of the topography of the coast on which they beach; that they have no idea they are swimming into whale traps - the same far-flung stretches of the continent that have been taking whales for perhaps 50 million years.

Ocean Beach on Tasmania 's west coast is the Australian hot spot for whale strandings. Adjacent to the port of Strahan , Ocean Beach stretches 35km north from the narrow mouth of Macquarie Harbour , which the convicts on Sarah Island first knew as "Hells Gates". Thousands of kilometres to the west, just before Kerguelen Island , one encounters the worst sea conditions on Earth. Here, in an area they call the Kerguelen Triangle, the weather is compounded by the effects of the east-flowing circumpolar current and the winds that form between the high pressure systems across Australia and the low pressure systems to the south. In January 1997 Raphael Dinelli, Thierry Dubois and Tony Bullimore, competitors in the Vendee Globe Round the World Yacht Race for solo sailors, were each to feel this force of the Southern Ocean. CSIRO oceanographer Steve Rintoul has analysed satellite data that shows, east of Kerguelen, hurricane force winds combine with waves more than 15 metres high. They drive all before them to the east, eventually pounding onto Ocean Beach making it a perpetual, roaring boulevard of surf.

Walk along Ocean Beach most days of the year and you will meet no-one and certainly hear nothing but the waves breaking on the fine white sand, sucking back before the next phalanx. At the high tide mark lies the flotsam and jetsam; the kelp, weed and drift­wood of the previous tides. Higher on the beach are giant logs that fell into the wild rivers of the west coast and floated out to sea, only to be flung back by the ocean surge. At the edge of the dunes, the fiercest storms have gnawed at the edge of the wilderness that borders the beach, exposing the roots of the she-oaks and the low brush that runs the length of the beach. Beneath the sand lie the bones of the cetacean corpses of the millennia, the generations and dynasties of sperm whales, pilot whales and dolphins that have stranded and died here, the graveyard at Hells Gates. In other stretches of the beach, particularly further north, are the "bones" of countless four wheel drive vehicles, their owners having been attracted to the wilds of the beach, unaware that the outwardly solid foundation of this beach belies a true heart of quick­sand. The mass of water that extends west beyond the beach, up and down its length, is charted but largely unexplored. Today we think we understand the forces that are at play beneath the waves, the sirens that have seduced whales to their deaths and which will contin­ue to do so.

At 5pm on February 3, a pod of 66 sperm whales swarmed into the shallows of Ocean Beach , across the mouth of Macquarie Harbour north of Cape Sorell . Some of the whales were huge, 15 metres long and weighing 30 tonnes. They were as hopeless and help­less as the youngest, a week-old calf that lay dead at the highest point of the beach, its navel still raw where the umbilical chord to its mother had detached. DNA tests of samples taken from the pod are likely to confirm that this was a nursery herd, consisting mainly of interrelated cows and calves. In the worst of male traditions, the bulls tend to come and go as nec­essary for breeding. Tests at the University of Tasmania may even reveal, in about a year's time, that this herd was related to two others that stranded at Marrawah and Stanley in Tasmania 's far north-west only days later. The well-intentioned attempts by locals and the Parks and Wildlife Service (PWS) to re-float some of the whales were largely futile.

"The general rule with sperm whales is that they will be difficult to rescue," says Hans Wapstra, the Hobart-based cetacean specialist with the PWS. "Because of their sheer size, they a die quickly They suffer massive internal injuries because of their unsupported weight. They also topple over then drown when their blowholes fill with water and sand. The only exception to the rule is if the animal is adjacent to a deep channel when it strands. Then it may be possible to nudge it into deeper water so that it can eventually make its way back out to sea. But these are rare occurrences. Very often, when they topple over, they roll onto a flipper, which loses its blood supply. The flipper is the animal's steering mechanism. If the animal is rescued it lists to one side because that flipper is not operating. The whale may complete one, two or three circles as it appears to be seeking to escape, but because it can't navigate properly it will eventually beach again. People interpret that as a determination by the animal to strand itself, whereas it simply cannot help itself."

Of the 66 whales that became stranded on Ocean Beach in February, 63 died and three were dragged and cajoled back out to sea. They later turned up dead, one at Trial Harbour (a matter of days later), one (which had its tail missing) at Bluff Hill Point and one "' at Robbins Island some three weeks later.  After the Ocean Beach stranding, the PWS dragged " the corpses over to the back of the sand dunes to bury J them above the high tide mark, beyond the reach of the roughest storm. They were buried with the adults at the bottom to deter human scavengers looking for their teeth and bones to use as scrimshaw. Days later, 35 sperm whales died at Marrawah and 11 at Black River Beach east of Stanley . The coincidence is unprecedented and is further support to the emerg­ing, preferred theory of why strandings continue to occur in the same locations. In the past 17 years, the death toll on this coast is considerable: 26 in January 1981; 65 pilot whales a year later; 178 in 1991 and now 112 sperm whales killed so far this year.  

Why? Wapstra says strandings would have occurred for the 50 million years that whales have been in the sea. In about 350 BC, Aristotle noted: "It is not known why they sometimes run aground on the seashore: for it is asserted that this happens rather fre­quently when the fancy takes them and without any apparent reason." The Romans reasoned that the whales had some-how offended Neptune and this was his punishment. The answer is complex, but there is an emerging body of opinion, particularly in the research institu­tions of Australia and New Zealand, that it is the whales' system of navigation, called echo-location, that is at fault; that it cannot detect the gradual shal­lowing of the sea as the whales approach coast lines with a topography of which Ocean Beach's is a classic.

Toothed whales — sperm whales, pilot whales and dolphins - are known to use echo-location or sonar to give them a mental picture of their surroundings. The animals produce very high frequency pulses that strike objects and return as echoes. The animal's brain uses that information to define nearby objects in terms of size, shape, proximity and even texture. Hence, if a whale approaches a steep underwater cliff face or a bluff, its sonar system warns it of the looming landfall and it can take diversionary action. However, a gently sloping beach and ocean floor may be undetectable to the whale.

A bio-acoustic research group within the Physics Department of the University of Western Australia has made a series of studies of the likely causes of live cetacean strandings under the supervision of Dr Ralph James. "The whale or dolphin emits a series of clicks of varying pitch and listens to the reflections of this sound from neighboring objects; fish, the sea floor and nearby geographical boundaries such as coast­lines. These clicks are produced with great intensity and can be as loud as a jet engine for some whales. Water has a property of being able to transmit these sounds over far greater distances than would be possi­ble in air and contributes to the capability of the cetacean to map out what lies in its vicinity with a clar­ity comparable to that of human vision."

The WA studies have found not only that there is substance to the gently sloping beach theory but also that the wind and the surf in the ocean shallows approaching the beaches affect echo-location. "The ocean during and after periods of prolonged weather can disrupt the cetaceans' sonar in two ways," James says. "Firstly, the noise of a storm on the sea sur­face is quite loud and may mask the cetaceans' hearing. Secondly, rain will generate bubbles on the sea surface that are mixed to low depths depending on water tur­bulence and may be present for several days after a storm has subsided. "My reading of Ocean Beach is that the site quali­fies as a classic whale trap, where a very gently sloping sandy beach presents major difficulties to the echo-navigation system of cetaceans."

James says a bio-acoustic analysis reveals that most cetacean species would be unable to perceive the shoreline there. "Although they clearly know the water is shallow, they may not be aware that a beach/stranding is imminent. This follows known data about how loudly they can emit their sonar signals and how well they can hear the return echo. The US Navy has the same problem with its submarines." James studied the depth soundings off the coast of Ocean Beach. He found that the depths dropped from zero on the shore to 20 metres, three kilometres out to sea. The slope is nearly flat; just half of one degree.

The WA studies confirm the earliest research car­ried out by Dutch scientist Dr Dudok van Heel in 1962. Van Heel used a Dutch naval vessel to test the theory of sonar navigation and found that gently sloping beaches would not supply a coherent reflection to pro­jected sonar and "this could provide difficulties to a whale or dolphin navigating by this method". He also found that sand stirred up from the bottom could help to mask accurate sonar navigation.

The theory explains any stranding that occurs as animals approach a gently shelving coastline and also explains why the events recur at the same locations year after year. While the Tasmanian hot spots of Ocean Beach and Stanley are among the worst in the Southern Hemisphere, Western Australia 's hot spots at Augusta and Albany on the south-west corner of the State also have a history of strandings.

Wapstra further believes that, with Ocean Beach , the position of the bluff of Cape Sorell to the south plays an important role. Imagine the pod is swimming down the coast, north to south, unaware land is close. The leaders pick up Cape Sorell on their sonar and therefore have to change course, to the left or to the right. Their echo-navigation gives them the same story on both sides, clear water. "They will get a strong reading from the headland," Wapstra says. "Because of what we know about the nature of the slope of the sea floor, the whales would have a 50/50 option, and a 50/50 chance of surviving. "If they turn left, they will find themselves in an extremely noisy and frightening environment. The water is shallower than it ought to be; they become panicked and finally the waves of the surf take over and drive them further inshore. As soon as they feel the bottom, they start to send out distress signals to the rest of the herd that they have grounded. "You must remember that these animals are proba­bly inter-related; in many instances these are nursery pods, so there is a strong social cohesion between them. When the others hear the distress signal, they gather round, they come close. They are not trying to rescue the animal in trouble, they just come close, they want to be supportive. All toothed mammals show this strong social cohesion and structure."

Bob Warneke, a Tasmanian-based specialist in marine mammals, agrees with the theories. He recent­ly prepared a whale rescue plan for Tasmania , having studied strandings since 1960. What still perplexes, however, is why the whales come in so close in the first place, given that the continental shelf, their normal geographical boundary, is at least 2km out to sea. "Generally the whales are looking for underwater canyons and upwellings of nutrient-rich water," Warneke says. "You find whales where there is an abundance of marine organisms. There is no clear answer about why they come in so close and, with the February standings, why they should have come in so close three times. Abalone divers here claim the inshore waters are warmer than normal; that may have some effect on the number of squid which is a favourite food of the sperm whale”.

Warneke says three strandings in a month is unprecedented. Normally Tasmania can expect about three strandings a year. Tasmania has more strandings than any other state of Australia ; the first ones here were recorded in 1802. Although Warneke is at a loss to explain the whales' proximity to the coast, he says these latitudes, called the Roaring Forties, are the home of the whale, that there is an abundant variety of cetaceans all along these lines of latitude. That is why most of the strand­ings are reported in Tasmania , Western Australia , New Zealand and South Africa .

The University of Western Australia research is examining whether the / fast-flowing Leeuwin current along the coast of Western Australia also plays a part. "The magnitude of flow and enrichment of biologi­cal life varies with La Nina and El Nino effects," James says. "During winter months meteorological condi­tions can shift the current inshore up to 100 kilome­tres, flowing only 3km from the coast instead of the usual 150 to 200km distance. A similar link between coastal currents off Tasmania and cetacean migration patterns may also be relevant."

Bob Warneke says the DNA testing will confirm whether there are close family links within what he also believes was a nursery herd that stranded at Ocean Beach in February. The testing, being carried out for the University of Tasmania by the Scripps Oceanographic Institute in California , will also deter­mine whether the sperm whale pods that stranded at Ocean Beach , Marrawah and Stanley were related. Dr David Obendorf was the veterinary pathologist who attended the Ocean Beach stranding. He doubts the wisdom of rescuers trying to manoeuvre sperm whales back out to sea given the trauma they have already suffered and the small prospects for their long term survival. "You have to have a viable unit to return to the sea. Unless it is a mature male, a single animal does not constitute that viable unit/' he says. With the three whales returned to the sea in February he says he had considerable reservations at the time for their long term welfare, reservations that turned out to be well founded. "The logistical problems with sperm whales are just so huge," says Obendorf. "I had one animal who was losing her uterus. Using bullets with sperm whales is a very tawdry business given the protection of the brain and just the sheer size of the animals. I had to drown her by pouring water down her blowhole. "With these animals, if you've done nothing for them in the first six or eight hours, it's virtually futile, it's just a salvage job."

The emotional drain on humans of whale strandings is indisputable. There is an evolutionary bond. Humans feel deeply emotional about distressed whales. The problem for those in authority on the beaches during rescues is that they can never set aside their emotions completely, yet scientists and veterinar­ians are expected to make rational decisions.

In the early seventies at Stanley a local man, Milton de Jonge, then about 15, went with his parents to the beach to look at a stranded pod of about 12 killer whales. Over the following three days they all died, but before they died de Jonge witnessed something that would live with him for the rest of his life. "The young ones could swim away from their mothers initially, but they kept coming back," he says. "Then they too became stranded; as they began to dry out they would begin to cry, letting out a high pitched squeal. Immediately their dying mothers would respond, flapping their tails in the shallows and splashing water over the calves. They were obviously communicating with each other at a time of great dis­tress, but I had this feeling of absolute helplessness. In hindsight, we should have put them out of their mis­ery straight away. I've found it very difficult to go to a stranding ever since."

Can anything be done? The bio-acoustics group at the University of Western Australia is carrying out some preliminary research on a warning system to sig­nal to incoming whales that they are approaching shallows or dangerous water. In Europe , a similar warning system is being developed to try to keep dol­phins away from tuna nets. "What we're looking at is a sentinel buoy, moored perhaps 100 metres out from the shore, perhaps slightly submerged," Ralph James says. "It would have its own sensor sonar that might emit a signal every hour to judge the Visibility' of the water in terms of how a whale might visualise it. When the sensor detected a dangerous situation it could then fire off a second set of sonar signals, per­haps once every 10 minutes, which would be picked up by the whales at their frequency It would alert them to the danger of the beach."

But it raises questions; would we then be interfer­ing in a natural but unusual stage of evolution? Has there already been too much attempted interference? In the evolution of the whale will there come a time when its echo-location will adapt to accommodate phenomena such as Ocean Beach and others like it; a gently sloping, but often fatal, gradient between the land and the sea, the whale's domain?