Sei whale
Balaenoptera borealis
By: Dagmar Fertl
Edited by: Poul Vendel
The name:
The name was formed from the Latin borealis for "northern". The
common name was formed from the Norwegian word seje for "pollack",
the fish, with which they are often found off northern Norway.
The look:
Sei whales can be confused with the fin of a Bryde's whale (in particular, the
latter). The dorsal fin rises at a steep angle from the back. Sei whales have
only one prominent head ridge, as well as a slightly arched rostrum with a
downturned tip. The sei whale is dark gray with a lighter underside. The back is
often marked with scars. Like other rorquals, throat pleats are present, though
they don't extend all the way to the navel as in other species. This whale has a
blow that can reach 3m high in the air.
The size:
Adults are up to 18 m in length and weigh as much as 30 tons.
The location in Africa:
They can be found anywhere along coastlines of Africa, with the exception
of far into the Mediterranean Sea. In winter, they are seen off the west and
east coasts of South Africa. Sei whales found off northwest Africa probably move
towards Norway and more northern waters in the summer.
Interesting facts:
Sei whales tend to stick often in groups of 2-5 individuals. These whales are
possibly the fastest swimming cetacean. Unlike other rorquals, sei whales skim
their food (instead of lunging), feeding on copepods and other small prey.
Human impacts:
In the past, these whales were hunted, but have since begun to recover from
exploitation in most areas.
Status:
Vulnerable.
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