Minke whale
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Balaenoptera acutorostrata

Names

AZORES : "Finbeque" - POR : Baleia anã - ITA : Balenottera minore - SPAIN : Ballena enena - GB : Minke whale - GER : Zwergwall - NEDER : Dwerg vinvis - SWEEDS : Vikval - NOORS : Vögehval. - DEENS : Vagehval - JAP: Koiwashi kujira

Biology

This species is the smallest Balaenopteridae. Their size rarely attains more than 10 m. The male adultsŐ average size is 8 m. The females are larger, measuring 8 to 9.5 m. Their weight varies between 5 to 10 tons. Newborns measure about 2.5 m and weigh up to 450 kg. Gestation lasts 10 to 11 months, and lactation takes at least 6 to 8 months. Females bear a single calf every 1 or 2 years. The minke whale can live for up to 30 years. The body is black to dark gray on the back, and light gray and white on each side of the body and along each pectoral fin, respectively. They have 230 to 360 pairs of white-cream baleen plates. There are 50 to 70 ventral grooves ending in front of the navel. Contrary to the other Balaenopteridae, this species feeds primarily on small fish, such as the harenk and the sardine, and they can eat krill as well. This animal produces low frequency sounds such as grunts, FM thumps and train sounds, between 0.06 and 14 kHz. Periodically, they emit high frequency sounds of 3.3 to 20 kHz

Observation

The team at Espaço Talassa did not encounter this species frequently, but we were able to detect them through the flight patterns and obvious agitation that numerous birds showed at the time these animals were feeding. The animals we observed were frequently solitary and sometimes in small groups of 2 to 3 individuals. Besides their small size, there are 3 distinct features of this species that allow easier differentiation from other Balaenopteridae species : an acutely pointed head that emerges first allowing the observation of the plates at the surface, a skin with no scars and distinctive white bands on each flipper. The movements of these animals are unpredictable, and they can disappear quickly, leaving no trail behind. They can remain submerged up to a maximum of 20 minutes. They can swim up to 13 or 16 knots for short periods, although normal speed is 2 to 4 knots. The blow is low and difficult to detect.

Cetaceans in the Azores