Sperm whale pod beached on Italian shore; 5 die

by Captain David Williams

On Thursday, 10 December 2009, a pod of sperm whales beached on Italy's southern coast (North of Varano Lake, Peninsula of Gargano, Apulia, Southeast Italy -- 41.920N at 15.743E).  At least seven died in what experts said was a rare and puzzling mass beaching for such a large species.   (see photo album and video)

BBC News - Sad mystery of Italy whale deaths--video news report

5 beached whales die off Italy

According to the SEAQUAKE THEORY,  if these whales were injured by pressure waves (seaquakes) above the epicenter of an undersea earthquake, they would have been guided from the epicenter to the stranding site by surface currents.   The theory indicates seismic pressure waves traumatized the head sinuses in such a fashion to disrupt echo-navigation and diving (seaquake-injured are not only lost, they can not dive and feed themselves). 

Depending on the degree of injury, storms at sea, and etcetera, the pod is usually able to avoid a stranding for ~30 days.  Thus, to find the earthquake responsible, one should trace back upstream to the nearest known habitat for the species in question and start looking around for a suspicious event.

The nearest upstream habitat for sperm whales is found near the Ionian Islands in the Ionian Sea.   

As it turns out, the current upstream from the stranding site flows From this habitat into the Adriatic Sea as illustrated by the red lines in the chart on the right.  In general, flow is inbound from the Ionian Islands moving in a north by northwest direction along the eastern shore of Greece through the Straits of Otranto, hugging the shores of Albania.  The surface flow through the Strait is characterized by a cyclonic horizontal shear that often generates eddies between the currents that flow into the Adriatic Sea and the currents that flow back into the Ionian Sea.  These eddies could hold the wounded pod for up several weeks without making any real forward motion.  This must be taken into consideration when estimating the time of travel. 

The surface current  enters into the Adriatic along the eastern shore and travels as far north as Croatia before looping west and then turning south to outflow from the Adriatic back into the Ionian along the eastern shore of Italy.

Past experience has taught us that the most dangerous earthquakes are reverse-thrusting events of ~5 magnitude or better with a depth of focus of ~10 km or less. 

The most likely event depicted on the left was most likely responsible.   It occurred on 3 November at 7:25 AM local time.  The epicenter was located at Latitude 37.35  Longitude 20.15. The depth of focus was listed as less than 10 km.  See USGS report at the bottom of this page, or get more info from European-Mediterranean Seismological Center.  Here you can examine maps, satellite data, witness reports and much more.

See also: Strong quake jolts Ionian Sea and Greek islands       

The epicenter is famous as the year round residential area of a large group of sperm whales.  In fact, the beached whales may have been the stars of a recent documentary film (Sperm Whales of Greece - Life in the Trenches | Whale Trackers). It's also likely that these sperm whales have been photographed many times in the last few years.  In fact, one of the scientist who has photographed sperm whales in this area many times  recently said:  "We have already identified one male individual that was well known from our work. He had been sighted 8 independent times in different years, starting from the year 2000." That one of the whales has already been identified as being a local resident of the waters near the epicenter is STRONG EVIDENCE that indeed the SEAQUAKE THEORY offers the only logical explanation for this mass stranding.

The seaquake-injured pod obvious swam with the flow of the current from the epicenter offshore of the Ionian Islands to the stranding site.  They were likely caught up in the one of the eddies, swimming in circles for several weeks.

See http://www.deafwhale.com for more information on the Seaquake Theory to explain mass strandings.

5.9 Mw - IONIAN SEA