Irrespective of the cultural, social and intelligence-related skills and the
associated moral implications, the following pages reflect the ecological state of
some whale populations. However, since data collection and analysis are extremely
difficult due to whales spending most of their time under water and being often
migratory, the information presented here is not absolute. Still it serves as a backdrop
for the complexity of the interaction between marine mammal ecology and
international law.
2.1.1 Blue Whale (Balaenoptera musculus)
The blue whale (Balaenoptera musculus) belongs to the family of baleen whales and
is the largest living species. The habitat of the blue whale extends over all oceans.
For this species, females are being used to determine the maximum body size since
they display a significant difference in size compared to males (sexual dimorphism).
The largest blue whales were thus females, caught in the waters surrounding the
South Shetland Islands and South Georgia, reaching sizes between 31.7 and 32.6 m.
In 1947, a female of 190 tons was caught at South Georgia. The normal weight of
blue whales ranges between 50 and 150 tons.
Although reference is commonly made to ‘the’ blue whale, the species is
subdivided into at least three sub-species: B. musculus intermedia, whose habitat
is in the Antarctic; B. musculus brevicauda with a habitat in Antarctic waters, in
the Indian and Pacific Oceans, commonly referred to as the pygmy blue whale;
and B. musculus musculus in the northern hemisphere. Rather dense populations
can be found in the North Atlantic and along the west coasts of North and South
America.
We must note, however that the term ‘dense population’ is relative. After all,
since the beginning of the nineteenth century the blue whale has been excessively
hunted due to its large size and associated commercial value. This resulted in a
drastic reduction of the population. For instance, in the hunting season of 1930–1931
almost 30,000 animals were killed. It is estimated that in the first half of the twentieth
century 325,000–360,000 blue whales were killed. This led to the blue whale
populations being close to extinction. Only in 1963 the International Whaling
Commission placed the blue whale under strict protection in waters south of 40
south latitude and 0–80
east longitude.
Due to the importance of the blue whale in international trade and in respect to
the dwindling populations, in 1945 the so-called blue whale unit (BWU) was
introduced. The BWU served as a reference for all hunted whales. One blue whale
corresponded to two right whales, two and a half humpback whales or six sei whales.
Although the BWU was used as an attempt to protect the blue whale it had the
opposite effect: whalers targeted larger animals to reach their assigned BWU limits
more quickly. As a consequence, the populations of blue, grey, right and humpback
2.1 Whales
15
associated moral implications, the following pages reflect the ecological state of
some whale populations. However, since data collection and analysis are extremely
difficult due to whales spending most of their time under water and being often
migratory, the information presented here is not absolute. Still it serves as a backdrop
for the complexity of the interaction between marine mammal ecology and
international law.
2.1.1 Blue Whale (Balaenoptera musculus)
The blue whale (Balaenoptera musculus) belongs to the family of baleen whales and
is the largest living species. The habitat of the blue whale extends over all oceans.
For this species, females are being used to determine the maximum body size since
they display a significant difference in size compared to males (sexual dimorphism).
The largest blue whales were thus females, caught in the waters surrounding the
South Shetland Islands and South Georgia, reaching sizes between 31.7 and 32.6 m.
In 1947, a female of 190 tons was caught at South Georgia. The normal weight of
blue whales ranges between 50 and 150 tons.
Although reference is commonly made to ‘the’ blue whale, the species is
subdivided into at least three sub-species: B. musculus intermedia, whose habitat
is in the Antarctic; B. musculus brevicauda with a habitat in Antarctic waters, in
the Indian and Pacific Oceans, commonly referred to as the pygmy blue whale;
and B. musculus musculus in the northern hemisphere. Rather dense populations
can be found in the North Atlantic and along the west coasts of North and South
America.
We must note, however that the term ‘dense population’ is relative. After all,
since the beginning of the nineteenth century the blue whale has been excessively
hunted due to its large size and associated commercial value. This resulted in a
drastic reduction of the population. For instance, in the hunting season of 1930–1931
almost 30,000 animals were killed. It is estimated that in the first half of the twentieth
century 325,000–360,000 blue whales were killed. This led to the blue whale
populations being close to extinction. Only in 1963 the International Whaling
Commission placed the blue whale under strict protection in waters south of 40
south latitude and 0–80
east longitude.
Due to the importance of the blue whale in international trade and in respect to
the dwindling populations, in 1945 the so-called blue whale unit (BWU) was
introduced. The BWU served as a reference for all hunted whales. One blue whale
corresponded to two right whales, two and a half humpback whales or six sei whales.
Although the BWU was used as an attempt to protect the blue whale it had the
opposite effect: whalers targeted larger animals to reach their assigned BWU limits
more quickly. As a consequence, the populations of blue, grey, right and humpback
2.1 Whales
15