Minke whale (Northern or common) Balaenoptera acutorostrata

The minke whale is the smallest of the baleen whales found in UK waters, and the commonest in Scotland. It is sleek with a very pointed head and small sickle-shaped dorsal fin, situated two-thirds of the way down its back. It is dark grey to black in colour with a white underside and a distinctive bright white band on the outer part of the pectoral fins. The upper jaw is flattened, with a central ridge that runs from the tip of the snout to two blowholes.

Behaviour

Minke whales are generally seen in small groups (pods) of between 1-3 individuals, except in rich foraging areas where as many as 15 individuals may gather. Research suggests that minke whales have a complex social structure, often segregated by sex, age and reproductive condition. Like other great whales, minkes migrate to temperate and tropical waters in winter and polar waters in summer.

The surfacing pattern of the minke whale is distinct with a swift, high, arched body roll. The minke’s maximum speed is around 40 km per hour, but they cruise between 5km to 25km per hour. Their typical dive sequence is five to eight blows at intervals of less than a minute, followed by a dive which can last up to eight minutes.

They feed using a strategy know as ’lunge feeding’. Longitudinal furrows on their throat allow the mouth to expand to engulf huge volumes of seawater. When they close their mouth, seawater is squeezed out through hanging curtains of baleen combs, whilst the fish are trapped and swallowed whole.

Adults (of 5-6 years) mate from January to May, the calves being born around December. Females produce a single calf that measures between 2.4 to 2.8 m and weighs around 450 kg at birth. Newborns can swim independently after just 30 minutes of birth.

Size

  • Length: 7 – 10 metres
  • Average weight: up to 5,400 – 6,800kg
  • Lifespan: typically 30 – 50 years

Status

Minke Whales, like all cetaceans, are protected as a European Protected Species.  It is a Priority Marine Feature in Scotland’s seas and included within two Nature Conservation Marine Protected Area proposals. The Scottish Wildlife Trust has recently (2020) welcomed the Scottish Government’s designation of a new Marine Protected Area, Europe’s largest, off the west coast of Scotland.

Distribution

Minke whales are widely distributed in relatively small numbers along the Atlantic seaboard of Europe, from Norway south to France, and in the northern North Sea. It is thought that a third of the North Atlantic whale population migrates to the Scottish west coast every year. They occur mainly in waters over the continental shelf (less than 200m depth) and can be seen close to land. In Scotland, waters around the Inner Hebrides, (between Coll and the Small Isles); the northern Minch (off the east coast of Lewis), west of the Isle of Skye and the Outer Moray Firth on the East Coast.

When to see

Best time between July and September, but they can be seen any time between May and October.

Facts

  • There are between 240 and 360 white/cream coloured baleen plates in each side of the upper jaw; these are coarse, hair-like structures (20-30 cm long) formed of keratin that hang down into the mouth acting like a sieve to separate fish from water.
  • Minke whales have earned the name “Stinky Minkes” because of the less-than-appealing smell of their exhaled air, which can reach a height of 2 metres, or more.
  • Minke whales are the smallest of the rorqual whales. The name rorqual referring to the 50-70 folds or pleats of skin under the lower jaw that allow the mouth of the whale to expand when it takes in large amounts of water for food.
  • Minke whales produce loud sounds (150 decibels) that can be heard a couple of miles away used for communication with other minkes.

Common name

Minke whale (Northern or common)

Species name

Balaenoptera acutorostrata

IUCN Red List status

Not endangered

When to see in Scotland

Best time between July and September, but they can be seen any time between May and October.

Where to see in Scotland

One of the best places to find whales (and dolphins) is in their feeding areas, such as the Straight of Corryvreckan (between between the islands of Jura and Scarba, Argyll). Check out the Scottish Wildlife Trust snorkel trails and coastal reserves such as Ben Mor Coigach and Handa Island.

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