Piton

Every time its name comes up in discussions or in the microphones of naturalists on the water, the same question comes up: why is it called “Piton”? Simply because it has a “piton” – or rather, a button, in good French – on its left flank! In addition to this protuberance, which gave it its name, this fin whale caught the attention of scientists around ten years ago, when members of GREMM and Fisheries and Oceans Canada placed a telemetric beacon on its back. This revealed that Piton dives to depths of between 0 and 140 metres! The aim of this project was to gain a better understanding of the species’ diet, depending on when, where and what it preys on.

After an absence of two years, Piton slipped into the St. Lawrence Estuary at the end of May, before the summer heat had set in. Several weeks later, the fin whale was still there, making his presence felt to those privileged to see his breath from between the waves. How long will Piton remain in the area? No one can say, but as long as there’s food to be found and his hunger isn’t sated, we can hope to see this rorqual for a while yet!

Piton comes into the estuary to feed. In 2015, GREMM and Fisheries and Oceans Canada fitted him with a tag. It recorded short, surface dives, V-shaped dives that were probably used to search for food, and U-shaped dives reaching 140 m. By comparison, the view from the hill at Anse à la Barque, in the Saguenay, is 110 m above sea level. The record-holding fin whale reached a depth of 470 m in the Mediterranean Sea. It’s hard to beat it in the marine park, where the maximum depth is 340 m!

A regular visitor to the estuary since 2010, and featured in the latest edition of the catalog Les grands rorquals dans le parc marin du Saguenay-Saint-Laurent, Bp942 was photo-identified by our research assistant in the Escoumins area on July 17. People in the whale-watching industry have given this fin whale the nickname “Piton”, referring to the slight protuberance on its left chevron – chevrons are the light grey, more or less contrasting “V”-shaped furrows that extend behind the blowhole and form different patterns for each individual. In the case of Bp942, the chevrons stand out clearly against the slate-gray body, a distinctive feature that is invaluable for identifying the animal, since its dorsal fin is very plain, with no particular shape or notch.

The phenomenal swimming speed of fin whales has earned them the nickname “greyhounds of the sea”: their peak speeds can reach 40 km/h! They are often spotted by cruisers and captains in the area, speeding along solo, in pairs or in groups of a few individuals. Their singular velocity is quite impressive, combined with the occasional splash and powerful blows that resembles a cannon shot.

In 2005, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) identified two fin whale subspecies: the southern hemisphere subspecies and the northern hemisphere subspecies. The northern subspecies, to which Bp942 belongs, was given the status of species of special concern in Canada by COSEWIC in May 2005. Nevertheless, the latest estimates indicate that the North Atlantic population is gradually recovering from the intensive hunting to which fin whales were subjected in the past. In Canada, the hunt ended in 1971, and a Norwegian station was active at Sept-Îles between 1905 and 1913, extracting oil from some 75 harpooned fin and blue whales a year. Today, however, ship strikes, noise pollution and the risk of entanglement in fishing gear are the anthropogenic threats that weigh heavily on these whales, justifying their current cautious status.

Bp942, nicknamed “Piton” because of the small protuberance on its left chevron, was first observed in 1999 and has been seen every year since 2010. Its dorsal fin is unmarked. It’s the high-contrast chevron and the small hump on its left side that make it stand out. Piton is in the latest version of the large whale catalog.

Last season, Piton was tagged by the GREMM-Fisheries and Oceans Canada team as part of the large whale tagging project, in partnership with Parks Canada. From 2:21 p.m. on August 12, 2015 to 5:40 a.m. the following morning, a telemetric tag followed the animal during its activities. The beacon, recovered at 8:35 am on the morning of August 13, enabled the team to discover what had happened underwater. From the time the beacon was retrieved until 12:30 a.m., Piton fed at the surface, between zero and 25 meters. Then, over the course of an hour, the whale made two exploratory V-shaped dives between 90 and 115 meters. From 1:30 a.m. to 4 a.m., the animal fed and rested on the surface. Finally, just before the beacon fell, Piton was feeding at depth, making U-shaped dives between 80 and 140 meters. The aim of this research project is to document the whales’ diet: when, where and what types of prey.

The 5th season of this project has just begun. Already, the team has put its research boat, the Bleuvet, in the water to try and track these individuals beneath the water’s surface. The target species are mainly fin and humpback whales, but also minke whales. Two or three times a week, from Tuesday to Thursday, you may have the opportunity to see the team at work on the water!