On February 19th the International Whale’s Day has been marked since the International Whaling Commission proclaimed a ban on whaling in 1986. For many decades of the 20 th century whale fishers have been hunting these marine giants for meat, whale bones, whale blubbers or bone flour. Eventually,the number of whale individuals significantly declined and many species found themselves on the verge of extinction. As an example, blue whales might be provided. Recent estimations of their population cannot find a common dominator; some claim that there up to 2 thousand blue whales in the World Ocean, others point out 15 thousand whales distributed over Northern and Southern hemispheres. In particular, blue whales are considered the crown jewel of the Atlantic Ocean, especially northern areas.
Blue whales are recognized as the biggest mammals on the Earth. The average weight is nearly 100-120 tones, which corresponds to a value of 40 African elephants. To support normal living a whale should consume 1 million calories per day that is usually comprised of krill (1 tone). Speaking of meal culture, it is impossible not to mention its peaceful nature, as far as blue whales are typical planktotrophics, which makes the situation with their extinction more sorrowful and distressing.
The other peculiar feature worth underlining is a specific way of communication between individuals. It is associated with whale songs, which are recognized by individuals on the distance of 1600 km. They are often observed during reproduction period, underlining the connection to family functions of mammals. This fact has alerted an attention of scientists and zoologists, dealing with gathering some facts about blue whales.
To be more précised, scientific interest is one out of two issues, which allow whales’ hunting. The other one is necessities of indigenous people in whale hunting. As a source of food it is not forbidden for the indigenous peoples of Alaska, the Far Eastern regions of Russia and Greenland, Saint Vincent and the Grenadines. Meat was the prime purpose of animals’ population decline; in particular, an adult blue whale individual can give about 40 tons of meat. The statistics concludes that during the 20 the century the number of whales decreased in 100 times.
However, hunting is not the only reason of blue whales disappearance. In this context, clashes with seacrafts are getting more and more serious. The average number of whale deaths from marine vessels is 1,2 accidents per year, but there are also true record years; for example, in 2007 4 fatal encounters occurred in the Pacific Ocean. Gulf of Saint Lawrence is also a region, where blue whales get lots of
injuries. According to marine observations the number of whales suffering from scars and wounds reaches 9-25%. The other negative effect sea vessels perform is a disturbance of echolocation abilities of whales. Voice signals are often silenced, which makes the communication and shoals’ formation almost impossible. It also influences on blue whales’ number within waters of the World Ocean.
Guest Post by Maria Kruk, an author for Species.com