Deep-sea fish tsunami hoax

Deep-sea fish washing up on Indonesian coastlines after the tsunami: fact or hoax?

February 13, 2004

Source: Joe Vialls (Australia)

I received an email from Joe Vialls indicating that numerous deep-sea species had washed ashore on the coast of "Plunket" (I assume he meant Phuket). The text read:

Deep Sea Creatures Found At Plunket Seaside After TSUNAMI

These claims are subject to verification. Anything circulating on the internet may turn out to be a hoax. This is a task for hoax-busters. Nevertheless, the photos presented show species typically inhabiting deep waters. One might speculate that if a major underwater explosion had occurred, the shockwave would have killed a large number of fish. This would be equivalent to "dynamite fishing," but on a much larger scale. Fish navigate their liquid environment in an unstable equilibrium, with parts of their bodies remaining compressible—for example, their swim bladder. When fish are killed by a shockwave, the heavier parts (the most substantial ones) sink to the bottom, while the rest float to the surface. If this shockwave were associated with a significant release of heat and the upward surge of a large volume of gas (which is not the case with conventional explosives), the dead fish could be carried to the surface by the powerful upward current generated. However, a proper examination of the fish would be necessary to determine whether they could have died due to an explosion. If it had been a nuclear explosion, the destruction of marine life could have extended over vast distances due to the pressure wave, even without radiation exposure. Another question: could the seismic shock that generates a tsunami be violent enough to kill many fish? As we will see later, after consulting specialists, the answer is negative. A tsunami like the one that devastated Indonesia can be compared to the uplift of an area the size of Switzerland in just a few minutes. This phenomenon involves colossal energy, resulting in the lifting of a massive volume of water, but in no way can this be likened to a violent impact.

Chimera

Another species of chimera

Silver hatchetfish

Report compiled by three specialists who have chosen not to have their names published on this page.

Deep-sea fish stranding. Analysis

According to websites:
http://www.snopes.com/photos/tsunami/creature.asp
(search for "deep" in the site's search engine).

http://www.users.on.net/~geoffn/seawolves/deep_fish

The photos circulated are not actually of fish stranded after the tsunami. They appear to be a hoax originating from Australia. However, a number of deep-sea fish were indeed found stranded (within 24 hours following the earthquake) along the coasts of Thailand and Sumatra Island!

The analysis below is based on these questionable photos, but it still retains relevance. The fish shown are normally found at depths between 500 and 1200 meters. Some of them may occasionally rise at night to depths of 50 to 100 meters. Others are typically found at depths ranging from 1500 to 2000 meters—this is unusual. Previous reports of fish strandings during Pacific tsunamis have sometimes covered entire beaches. However, eyewitness accounts mention only surface fish—severely crushed by the force of waves hitting the seabed. The exact cause of death for these deep-sea fish remains currently unknown or unreported. We do not know the results of any potential analyses conducted on these fish. Likewise, the reasons for their ascent from the abyssal depths remain speculative.

Hypotheses regarding the cause of death

1/ Hypothesis of death upon stranding
Fish brought up from the deep (see hypotheses for ascent) are carried by tsunami waves toward the coast, where they strand and die.

Counter-argument: This hypothesis does not hold. Beneath the surface layer of water undergoing horizontal oscillation, once the seabed exceeds the wave height, water movement becomes imperceptible. Divers who were underwater reported nothing unusual. Those who noticed anything merely observed a large influx of sediment rising to the surface, which then settled and clouded the water down to the seafloor. Even the fastest possible ascent rates (30 meters per minute / 500 meters = 16 minutes) for these fish, combined with their usual habitat depth, do not allow them to reach the surface at the moment the tsunami forms, as the initial wave crest forms almost instantaneously (due to the incompressibility of water).

2/ Hypothesis of poisoning
Fish are killed at depth by the release of toxic substances trapped in Earth's crust. Their corpses are then brought to the surface (see ascent hypotheses), carried by surface currents, and eventually strand on beaches.

Counter-argument: The release of toxic substances during an earthquake is usually linked to the exposure of previously hidden geological layers. While this phenomenon is possible, it has not been documented in cases of tectonic plate subduction, such as the one on December 26, 2004, off Sumatra.

3/ Hypothesis of shockwave
Fish are severely affected by a shockwave generated by the earthquake. Once brought to the surface, either dead or stunned (see ascent hypotheses), they are carried by surface currents and strand on the shore.

Counter-argument: An earthquake, even of magnitude 9, is not an explosion. Indeed, the December 26 quake lifted an area the size of Switzerland by 5 meters—but this movement occurred over three minutes, meaning it was much slower than any elevator. This is nothing like an explosion capable of stunning or killing fish. One might argue that the first few centimeters of uplift were faster, but even at 1 meter per second, this remains far from a phenomenon capable of generating a shockwave lethal to fish.

Hypotheses for ascent

1/ Thermal ascent
A temperature increase linked to the earthquake causes a rapid rise of a hot column of water, dragging fish upward toward the surface.

Counter-argument: The December 26 earthquake was not associated with a submarine volcanic event. There is no reason to believe the local temperature rise would differ from that of a typical subduction-zone earthquake on land—i.e., negligible. Moreover, the fish visible in the photos are not "cooked"!

2/ Gaseous ascent
Significant gas emissions may have occurred from the disturbed zone. In particular, methane release near a subduction zone is conceivable. The stream of bubbles generated then creates an upward current. The reduction in density of the seawater-gas mixture decreases the buoyancy of solid objects within it, but the upward speed of the bubbles is also transferred to these solid objects. This results in...