Mass stranding in the Ionian Sea

Yesterday, November 30 there was a mass stranding of beaked whales Ziphius
Cavirostris in the Ionian Sea.

The first reports came in from Corfu with three animals washing up alive, although two died and the disposition of the third so far in unknown.

A second report of a female and juvenile stranding on the coast of Calabria 120 nautical miles west of Corfu. The female perished, the disposition of the juvenile is currently unknown.

While there is as of yet no direct evidence of human agency, two independent observers (separated by 23 km) near the Corfu location commented that they heard “whistles” while approaching the single animals. “The ‘whistles’ were heard even out of the water at a distance of 100 m from the animal (!), and became much louder when the rescuers entered the water to approach the animal.”

This would be consistent with mid frequency sonar signals akin to noises associated with previous beaked whale strandings. Being able to hear these signals out of the water at such a distance would indicate that they were quite loud.

Additionally a local fisherman from the area said that he saw an “unusual” research vessel offshore that he believes was performing research for oil. (It is known in the area that seismic surveys have started or are about to start.)

Why beaked whales are so susceptible to mid-frequency sonar assaults and the pathology in their deaths is debated (and may vary). Some believe that the loud sonar itself damages or destroys their hearing organs. This was substantiated in necropsies performed on the 2002 Bahamas victims by Darlene Ketten who found hemorrhaging in the acoustical lipids their jaws.

Others believe that the beaked whales are susceptible to the extreme and edgy physics found at depths of 1000 meters where they forage, so that extreme noises may cause their tissues to bubble or boil.

Still others believe that when foraging at these depths, the noise deafens and consequently terrifies them causing them to surface faster than their internal pressure mediation systems can accommodate, so nitrogen boils out of their blood and air expands in their bodies – more-or-less emulsifying their organs as they race to the surface.

Inquiries are being made. According to a number of regional agreements this area is protected and that proposed use of any signals above 140dB (re: 1uPa) needs to be covered through and Environmental Impact Assessment process.

It has been much over a year since the last noise-associated beaked whale stranding was cataloged. I was beginning to think that we were seeing the results of the mitigations and raised awareness promoted by the conservation community. But as this event indicates, we are not out of the woods yet.

We will keep you posted as we hear more on this latest tragedy.