The fin whale, the second largest living mammal, has been severely impacted worldwide by commercial whaling. Nearly 750,000 animals were killed in areas of the Southern Hemisphere alone between 1904 and 1979, and they are rarely seen there today. Their current status is unknown in most areas outside of the North Atlantic.
The fin whale is the world’s second largest animal after the blue whale. They can dive to depths of 230 metres and make low-frequency noises (infrasound) which can be as loud as 188 decibels. These sounds cannot be heard by humans, but can be detected by other fin whales up to 850 km away. An individual fin whale is identified by the pattern of light-coloured chevrons on its back as well as by the size and shape of its dorsal fin. Records of females have been found with multiple foetuses, but it is unlikely that more than one would survive. The oldest specimen captured in Antarctica was 111 years old. Fin whales have also been known to mate with blue whales and to produce first generation offspring.
Growing up to 27 metres long and weighing as much as 120 tonnes, the slender body of the fin whale is capable of speeds of up to 37km/h, with brief bursts of up to about 47km/h which led to its nickname, ‘greyhound of the sea’. The upper half of the body is dark grey or brownish, while the belly is white. The head has a single medial ridge and has distinctive asymmetrical markings: on the right side the lower lip, mouth cavity and baleen plates are white, whereas on the left these features are dark. The fin whale has a small, falcate dorsal fin and slightly concave trailing edges to its flukes, which are rarely raised out of the water.
The fin whale feeds on animal plankton (including krill) and schooling fishes, lunging to take in great quantities of water and prey, then filtering the water out through its baleen plates leaving the prey trapped inside its mouth. When a fin whale eats it often turns on its side with the right side facing downward; in this position the lighter head colouration makes it less visible to prey. The fin whale generally travels alone or in pairs, and rarely breaches or spyhops. Its exceptionally large size, asymmetrical head colouration and small dorsal fin are probably the best identifying features. Overall range and distribution is not well studied but they are known to inhabit primarily pelagic habitats of both northern and southern hemispheres. Most populations are thought to be migratory whilst several resident populations are known to exist in the Gulf of California, East China Sea and the Mediterranean.
With krill reduced, will they go too? Fin whales have been greatly affected by historical hunting, mostly due to their economically valuable blubber, oil and baleen. The recovery of the southern hemisphere fin whale may be undermined by, among other things, a reduction of Southern Ocean krill due to climate change.
Pollution: Fin whales are also threatened by habitat degradation. In some regions they have been shown to carry high levels of pollutants such as heavy metals, PCBs and other organochlorine compounds that accumulate with age and transfer between mother and calf during nursing. These substances can cause health and reproductive problems in cetaceans.
Ship strikes: Boat collisions are another serious cause of fin whale mortality, particularly in areas with high-speed vessel traffic. A dead fin whale that was washed ashore in south-west England in early 2010 is believed to have been the victim of a ship strike.
Bycatch: They are also vulnerable to incidental catches in fishing gear, but less so than many other cetacean species.
Whaling: Whaling remains a threat for this species. In 2006 Iceland resumed commercial whaling and in 2009 set a quota for 150 fin whales over 5 years – to date 125 fin whales have been harvested – despite the species’ status as “Endangered”.
Note: Japan is also set to return to a full-scale commercial whaling on the high seas, a move currently blocked by the International Whaling Commission (IWC). But the Japan government has consistently ignored objections and resolutions from the IWC against its scientific whaling and has even ignored a decision by the International Court of Justice that they close down their whaling activities as undermining the IWC. The new Japanese legislation includes funding to repair the aging whale ships being used for the current bogus “scientific” whaling and guarantees funding for whale “research” in the future. Furthermore, the new legislation allows Japan to send vessels to Antarctica with the fleet specifically to deal with harassment from such organizations as the Sea Shepherd Conservation Society, which seeks to interfere with whaling activities they contend violate international law. (Memo to Japan government: Sea Shepherd is right.)
Japan has also moved to stop interference with their illegal whaling operations by declaring that anyone who opposes whaling and the killing of dolphins is a terrorist.
Apparently, simply witnessing and documenting the slaughter of dolphins in Japan will now be a crime and classified as terrorism.