Do minke whales employ unique feeding strategies in the Saguenay Fjord? 

Certain individual whales show a marked preference for specific feeding sites. Numerous anecdotal observations suggest that these individuals develop feeding strategies that are adapted to their preferred feeding area. The minke whales that frequent the Saguenay Fjord, a limited habitat with specific physical characteristics, are the ideal subjects for the verification of such a hypothesis.

To go through the looking glass

Researchers compared feeding-strategy data collected on minke whales present in the Laurentian Channel between 1997 and 1999 with data collected on minke whales present in the Saguenay Fjord between 2001 and 2003. These data included detailed descriptions of all visible surface behaviour. From 2001 to 2003, they also closely observed five photo-identified minke whales that visited the Saguenay Fjord on a regular basis to feed.

In short

Loca's head slap (Photo ORES)

The feeding strategies of the minke whales that visit the Saguenay are different than strategies employed by minke whales that visit the Laurentian Channel. The physical properties of these two areas may explain the variance. In the Saguenay, minke whales spend a considerable amount of time herding prey near the surface. To do so, they regularly perform chin up blows, underwater exhalations on the dive and head slaps (see "I want to know more"). The Laurentian Channel deep-water upwelling—created by tide, currents and underwater topography—naturally musters minke whale prey near the surface. Consequently, minke whales execute fewer herding manoeuvres in this sector. There are also differences in the use of various feeding strikes; Saguenay minke whales use lateral and ventral manoeuvres more often, while those present in the St. Lawrence are more prone to execute oblique manoeuvres.

Observations made in the Saguenay between 2000 and 2003 have led researchers to believe that minke whales in this area may be learning and transferring feeding strategies among themselves. The head slap was noted for the first time in 2000 when a minke whale known as Loca was seen executing this manoeuvre in the Saguenay. The head slap consists of pushing the head and part of the thorax out of the water only to let it fall back energetically against the water’s surface. The number of minke whales executing this particular manoeuvre in the Saguenay increased from one in 2000 to six in 2003.

Project leader

Ned Lynas, Ursula Tscherter, Jordy Thomson and Katie Kuker of Ocean Research and Education Society (ORES)

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