On April 14th, we received from the Director of the Marine Protected Area of the Islands of Ventotene and Santo Stefano the report of the sighting of a large cetacean in Frontone, Ponza Island. The video shot by the Local Coast Guard showed a large cetacean with a double blowhole typical of Mysticeti. The absence of the dorsal fin, the scars/white spots around the blowhole, and the dorsal crest led to the identification of the species: gray whale (Eschrichtius robustus).

Frames extracted from Coast Guard video of Ponza, the first report of a gray whale in Italian waters.

This is the first gray whale (Eschrichtius robustus) recorded in Italian waters, and the second in the Mediterranean after another individual, which appeared in 2010 (Scheinin et al., 2011) in Israel and then Spain. In May and June 2013, a gray whale had been sighted off the coast of Namibia (Hoare, 2013) the first confirmed in the southern hemisphere.

 

About gray whales

Once common throughout the Northern Hemisphere, gray whales are now regularly found only in the North Pacific Ocean, where there are two surviving populations, one in the eastern North Pacific and one in the western North Pacific. North Atlantic populations were extirpated (perhaps by whaling) on the European coast before 500 AD, and on the American coast around the late 17th, early 18th centuries.

Commercial whaling quickly drove even Pacific populations to extinction. In the 1930s and 1940s, international conservation measures were enacted to protect whales from overexploitation, and in the mid-1980s the International Whaling Commission (IWC) instituted a moratorium on commercial whaling.

Today, the Eastern Pacific population has fortunately recovered and numbers about 27,000 individuals migrating between the waters off northernmost Alaska and Baja California. The western Pacific population, on the other hand, is at risk of extinction, with an estimated population of fewer than 300 individuals migrating between the Sea of Okhotsk (Kamchatka, Russia) and southern Korea.

Gray whales are known to be curious about boats in some locations and are the focus of whale watching and ecotourism along the west coast of North America. Gray whales make one of the longest annual migrations of any mammal, traveling approximately 10,000 miles round trip and in some cases up to 14,000 miles.

The presence of this specimen in our waters could perhaps – even if it is only a hypothesis – represent a return of this species to the Atlantic, from which it had been exterminated by hunting three hundred years ago. The only plausible route by which Pacific whales could reach the Atlantic, it is believed, is through the waters of the Arctic, now increasingly free of ice.

 

Wally in our study area

In total, in our study area have been reported 4 sightings of the same specimen of the gray whale, after Ponza the animal has been sighted in Sorrento, Baia, and then Gaeta. The animal has been nicknamed Wally.

Grey whale sightings in the study area

During the sighting of Sorrento, on April 17, thanks to a live broadcast on Facebook it was possible to document how the behavior of observers who followed the whale has been incorrect. Surely without realizing the disturbance caused, the boats have approached too close to the animal, trying to touch it, cutting the course, and sailing on it with the propellers at a dangerously close distance. As a result, with the collaboration of the Marine Protected Areas Regno di Nettuno, Ventotene and S. Stefano, Gaiola, and Campi Flegrei, a “simplified” code of conduct was disseminated to teach sailors how to approach a cetacean at sea. The code of conduct was subsequently taken up and divulged by the Committee for the Protection of the Sea, made up of 18 local environmental associations which have ensured its widespread diffusion throughout the territory.

During the sighting that occurred in Baia, on April 18, the gray whale came very near to the coast, up to a depth of about 3 meters near Lucrino. The shallow water in which the animal was sighted has alarmed both the enthusiasts who followed the event and the Coast Guard, which in these cases is trained to intervene with emergency, to avert the possibility of stranding. However, this species, unlike the other Mysticeti, rarely feeds along the water column, and usually “plows” the sandy bottom to feed on small crustaceans from the sediment of the seabed, even in very shallow water.

To coordinate the interventions of the different Coast Guard units and to provide univocal indications to the Operational Command, a group of experts was formed, initially including CERT (Cetacean strandings Emergency Response Team), the Tethys Institute, and Oceanomare Delphis. The group then expanded to include numerous other associations that contributed to monitoring Wally’s further movements along the Italian coasts.

 

Size measurement

In the following days, Wally continued his exploration of the Mediterranean moving northwards and reaching the port of Fiumicino, Viareggio, and arriving as far as the Ligurian coast. On April 28 researchers from the Tethys Institute, together with the Coast Guard, were able to establish the exact dimensions of the gray whale using the technique of aerial photogrammetry.

Aerial photogrammetry of Wally

The precise dimensions of the animal were important for a correct estimation of its age and to try to solve the “mystery” of its origin. Two different theories were advanced: that Wally could have been born this winter and therefore represent a return of the species in the Atlantic where it is considered extinct, or that instead, it was a calf of the previous season, and that it had had time to migrate from the Pacific through the Arctic waters.

Wally measures 7.70 m and is therefore a very young animal.

All the material collected was sent to two gray whale experts: Robert Brownell of NOAA (National Oceanic and Atmospheric Administration) and Jorge Urbán of the Autonomous University of Lower California. Although the length is shorter than not only the average of one-year-old individuals, but also of smaller ones, pigmentation and appearance made both researchers lean towards a baby born in January 2020 in Baja California or a little further north, and that once arrived in Arctic waters took the Atlantic instead of descending the Pacific. Subsequent inadequate feeding would then have prevented it from growing up like its peers.