whales were massively reduced. Only in 1972 the BWU was abandoned and
replaced with species-based quotas.
5
The current population of the blue whale is labelled as ‘endangered’ by the IUCN
although the population trend is increasing. It is estimated that there are now around
10,000–25,000 adults worldwide, corresponding to around 3–11% of the original
population size.
6 Since the populations of blue whales are small, all whaling nations
have banned the hunt for blue whales for commercial or other reasons.
7
2.1.2 Fin Whale (Balaenoptera physalus)
The fin whale (Balaenoptera physalus) is a close relative of the blue whale and it is
estimated that there is at least one hybrid amongst 500–1000 fin whales. Only
recently the high degree of hybridity between these two species has been made
public when Icelandic whalers seemingly landed a blue whale which is strictly
protected under Icelandic law. Upon closer genetic inspection, this whale, however,
proved to be a hybrid between blue and fin whale.
8
As in the case of the blue whale, sexual dimorphism in fin whales also favours
females since they are on average 5–10% longer than males. Fin whales in the
southern hemisphere reach as much as 25–26 m while their northern relatives are
around 21–22.5 m long. The mass of the fin whale ranges between 40 and 50 tons in
the northern hemisphere and 60–80 tons in the south. The habitat of the fin whale
extends into all oceans, except the polar regions. Up to the point of writing, no fin
whales have been spotted in the Black Sea and are rare in the eastern Mediterranean,
in the Baltic Sea, in the Persian Gulf, in the Red Sea and close to the equator. The
highest population density can be found in temperate and cold water, although we
must remember that the fin whale is a highly migratory species. It is surmised that fin
whales form single independent groups for reproduction. Since the fin whale is a fast
swimmer with a large body size, apart from the killer whale/orca (Orcinus orca) the
fin whale does not have natural predators.
9
Throughout the nineteenth and twentieth century the fin whale was one of the
most overhunted whale species. Within a time period of approximately 30 years in
which the fin whale was hunted in the North Atlantic, its population had declined to
such a degree that already in 1904 whaling stations which were specialised on fin
whales had to close down. As a consequence, the hunt for fin whales moved into
other regions of the North Atlantic, then into the Antarctic, the Pacific and finally
into the Indian Ocean. For the years 1935–1970 it is estimated that 30,000 fin whales
were killed annually. Only with the coming into force of the whaling moratorium in
5 Gillespie (2005), p. 4.
6 Cooke (2018a).
7 Sears and Perrin (2008), pp. 120–124.
8 McGrath (2018).
9 Aguilar (2008), pp. 433–437.
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2 Marine Mammals: Some Basics
replaced with species-based quotas.
5
The current population of the blue whale is labelled as ‘endangered’ by the IUCN
although the population trend is increasing. It is estimated that there are now around
10,000–25,000 adults worldwide, corresponding to around 3–11% of the original
population size.
6 Since the populations of blue whales are small, all whaling nations
have banned the hunt for blue whales for commercial or other reasons.
7
2.1.2 Fin Whale (Balaenoptera physalus)
The fin whale (Balaenoptera physalus) is a close relative of the blue whale and it is
estimated that there is at least one hybrid amongst 500–1000 fin whales. Only
recently the high degree of hybridity between these two species has been made
public when Icelandic whalers seemingly landed a blue whale which is strictly
protected under Icelandic law. Upon closer genetic inspection, this whale, however,
proved to be a hybrid between blue and fin whale.
8
As in the case of the blue whale, sexual dimorphism in fin whales also favours
females since they are on average 5–10% longer than males. Fin whales in the
southern hemisphere reach as much as 25–26 m while their northern relatives are
around 21–22.5 m long. The mass of the fin whale ranges between 40 and 50 tons in
the northern hemisphere and 60–80 tons in the south. The habitat of the fin whale
extends into all oceans, except the polar regions. Up to the point of writing, no fin
whales have been spotted in the Black Sea and are rare in the eastern Mediterranean,
in the Baltic Sea, in the Persian Gulf, in the Red Sea and close to the equator. The
highest population density can be found in temperate and cold water, although we
must remember that the fin whale is a highly migratory species. It is surmised that fin
whales form single independent groups for reproduction. Since the fin whale is a fast
swimmer with a large body size, apart from the killer whale/orca (Orcinus orca) the
fin whale does not have natural predators.
9
Throughout the nineteenth and twentieth century the fin whale was one of the
most overhunted whale species. Within a time period of approximately 30 years in
which the fin whale was hunted in the North Atlantic, its population had declined to
such a degree that already in 1904 whaling stations which were specialised on fin
whales had to close down. As a consequence, the hunt for fin whales moved into
other regions of the North Atlantic, then into the Antarctic, the Pacific and finally
into the Indian Ocean. For the years 1935–1970 it is estimated that 30,000 fin whales
were killed annually. Only with the coming into force of the whaling moratorium in
5 Gillespie (2005), p. 4.
6 Cooke (2018a).
7 Sears and Perrin (2008), pp. 120–124.
8 McGrath (2018).
9 Aguilar (2008), pp. 433–437.
16
2 Marine Mammals: Some Basics