Blue Whale (Balaenoptera musculus)
Many people have seen blue whale in newspapers and tv or internet but very few have witnessed them actually living in our ocean.iterally they are being inhabited in all oceans except acrtic ocean.Most places where blue whale are seen considered them as migration animal but very specific places like mirissa sri lanka they have seen all year around.
Blue whales body is long, somewhat tapered and streamlined shape.It’s rostrum broad and flat, almost u shaped with a ridge that extend just a forward of the blowholes to the tip of snout. Dorsal fin is falcate shaped and it’s the smaller compares to other baleen whales. It’s fluke are very broad and often remora fish stuck to fluke and some barnacles too.
There are 55-68 grooves in lower jaw extending near to narval, that grooves can expand tremendously which help to take tons of krills with massive amount of water and then filtered through baleen plates leaving food in mouth then swallowed. Blue whale has baleen plates instead of teeth, baleen is made of keratin (finger nail like material)and attached to whale’s upper jaws.
Mottling pattern of a blue whale is quite unique and blue and grey color visible in surface although blue in underwater.it has to come to surface to exhale and takes few deep breaths and we have observed blue whale comes to surface to breath every 10-12mintutes in normal behavior. It’s pair of nostrils called blow hole and when they exhale misty form of water droplets sprayed up called blow. Normally a blow heights up about 9m and very helpful for whale watchers to observe even from long distance.They often found in single or groups but most common is blue whale pairs. They also communicate each other in short or long distance as blue whale creates low frequency loudest call which ever a animal can make around 188 dB
Blue whales are endangered animal and gives birth to new calf every 2-3 years and once calf born will feed from mother’s milk which is high concentrate of fat and nutrients. Calf will feed on milk around two years until it’s able to survive with it’s own findings.
Killer whale and great white shark is main predator of blue whales,specially when travel with calf killer whales try to take apart the calf and kill it.so the mortality rate of blue whale calfs is so high.Other main reason for blue whale death is Collison with ships, even in sri lanka thousands of cargo and passengers ships are crossed through where blue whales are mostly seen. there are several bodies with severe cuts washed to shores of sri lanka per year.