When whales surface, they show only one twentieth of their body. One should therefore expect to see just their back and dorsal fin, if they have one. Occasionally, much to the delight of observers, whales display more of their bodies. This week, several whales showed their fins to the skies!

Rorqual à bosse DogEar © Anik Boileau, CERSI
Humpback Whale DogEar © Anik Boileau, CERSI

First, in the Sept-Îles region, the CERSI the team observed about twenty humpbacks. It was easy to recognize DogEar, with the curved right lobe of its caudal fin, a surprising feature when encountering this whale for the first time and it raises its tail before diving. This humpback had been seen a few days earlier in the Mingan sector. A whale’s caudal fin is used essentially to propel the animal with up-and-down movements created by powerful muscles along the peduncle. One would think that a whale with such a tail might have trouble getting around, but these animals seem well adapted to their condition.

It wasn’t just the tails of humpbacks that were seen in the Sept-Îles region; surface feeding fin whales also lifted their large pectoral fins out of the water, pointing them to the sky. Mouths gaping, these “gulpers” rolled onto their sides to take in mouthfuls of water teeming with prey, which they then filter with their baleen. It’s an impressive sight, as this appendage is long and straight.

Humpback whales have the longest pectoral fins of any cetacean, measuring over four metres, or one third of their body length! What a show, watching these whales in the Gaspé region lift their large serrated fins and slapping them loudly onto the water! When observing humpbacks through clear water below the surface, they appear to be flying under the sea.

Queue de rorqual bleu © GREMM
Tail of a blue whale © GREMM

In terms of tail size, the record belongs to the blue whale, at six to eight metres wide. This week off Les Bergeronnes in the Côte-Nord region, a blue whale showed its tail before disappearing into the deep waters of the Estuary. Fewer than 20% of blue whales in the St. Lawrence lift their tail in the air before diving.

The Mingan Island Cetacean Study (MICS) had the chance to observe a few coal black, smooth-edged tails being raised out of the water again this week. Such patterns are characteristic of North Atlantic right whales. At least five individuals are still present in Jacques Cartier Strait, between the North Shore and Anticosti Island. These heavy and portly whales most likely use their tails to probe.

H824, la baleineau de Quill © MICS
H824, the calf of Quill © MICS

Tails can also facilitate the identification of individuals that visit the St. Lawrence. In the case of H824, the calf of Quill seen recently in the Mingan region, its tail is unique and bears the scars of killer whale bites, according to the MICS team. Born in 2015, this calf already showed these markings in 2016. Most killer whale attacks on calves occur when the latter are just a few months old and are migrating north with their mothers to reach their feeding grounds.

Observation of the Week - 18/8/2016

Josiane Cabana

Josiane Cabana served as Director for the Quebec Marine Mammal Emergency Response Network call centre from 2011 to 2018. When she’s not responding to cases of dead or vulnerable marine mammals, she likes to take the time to educate local residents on the threats faced by these animals. Biologist by training, she has been involved with the GREMM for more than 15 years, and always with the same undying passion!

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