At the turn of the 20th century our vast oceans were a plenty with baleen whales. What has happened to them? The Blue Whale is the largest baleen whale and the biggest living creature to ever breathe on our planet. These creatures make sounds that travel hundreds of kilometres yet we cannot hear these sounds without special equipment. They also eat thousands off kilograms of food every day and they live as long as we do. blue whale bitten in half 2021
Scientists and oceanographers are constantly carrying out research on the Blue Whale in attempt to assist in the survival of this magnificent creature which experts now estimate number less than 10 000 worldwide. Up until recently, one of the greatest mysteries of the sea was where these whales are born.
Most of the time Blue Whales swim far off shore only surfacing for brief periods usually for only a few seconds at a time. In late summer however many of these creatures gather to feed. Researchers then have a chance to tag them. They can then track them during the winter migration south with satellite tags. With this information, researchers have discovered that these whales mate and give birth in the tropics.
Blue Whales feed during the winter when they mate and give birth. They are twice the size of more commonly known whales. Experts know little about them. An adult female Blue Whale can weigh almost 180 tonnes which is heavier than 25 fully grown elephants. The heart alone is the size of a small car and weighs close to 500 kilograms. They grow to be as long as three buses.
Blue Whales do not have teeth. When they open their mouths, pleats of skin allow their throat to expand letting them suck in krill and tiny crabs. Plankton and krill makes up nearly all of the diet of the Blue Whale. The largest animal on the planet feeds on one of the smallest. It takes around one metric tonne of krill to fill a Blue Whales stomach and they can devour three and a half tonnes of these small shrimp-like crustaceans every day.
Cousins of the Blue Whale, humpbacks, generally do not eat during the winter months when they are mating and calving. Blue Whales, however, are three times heavier than their relatives. Blue Whales are so big that they need to eat continuously to keep up their energy levels all year round. Mating and calving require these giants to expend energy and a productive place to provide the fuel.
Blue Whales can also make some of the loudest calls of any animal but we require special technology to hear them. Scientists are capable of decoding certain sounds made by certain whales and attempt to interpret what they may mean by comparing the acoustic signals to the behaviour observed.
Scientists attach probes to the whales via a suction. The tags record how deep the whales dive, its pitch and roll and how it approaches its prey. These probes are also used to record surrounding sounds. The sounds the researchers are particularly interested in are the sounds of ships in the shipping lanes. The researchers hope that the information from these probes can answer questions such as how loud the sounds of the ships are compared to the whale and whether and how the noise from these ships affect the whales. The data may reveal whether the whales’ voracious appetite places them in peril from the shipping lanes. They use this data to identify danger zones.
Some of the higher density areas that Blue Whales use and return through every summer to feed are intersecting with areas of increasing shipping traffic. Ships are now not only becoming more numerous but they are bigger and faster as they supply more and more goods to the harbours of the world. This is the recipe for disaster for the whales. Could it be that after surviving the sharks and the whaling that ships strikes now pose the biggest threats to the survival of the Blue Whale?
Research offers the best hope for new shipping paths that will give the largest of the baleen whales the space they need. The challenge for protecting the Blue Whales has only just begun. For these almighty animals to have a chance we must respect the oceans for the decades ahead… for all creatures great and small….but in this case mainly for the great.