Blue whales. Whats coming to your mind when hear that words? Yeah you right, blue whales is large mammals in the ocean ecosystems. Blue whales also considered as largest animal who ever live in the world, which means they’re larger than dinosaurs and elephant. Unfortunately, recently blue whales classified into endangered one because there are illegal hunting of blue whales in some countries and it caused population of blue whales decrease dramatically. Do you know whats caused it? How many blue whales left in this world? Are they have so many predators so they become endangered one? There so many question in our mind when talk about species who live in ocean, and so here we are, talk about blue whales!
Physical Description and Unique Behavior
Blue whales is the largest animal in the world (larger than elephant though) and during 20th century was almost exterminated due to commercial whaling. This species already slowly recovered because global whaling ban but its still classified as endangered one and still have serious threats, such as ship strikes and impact of climate change. Like all rorquals, the blue whales is slender and stream line with their head is broad and U-shaped.Their flippers are long and pointed also place above three-quarters of the way back from the snout tip.
Blue whales are bluish grey dorsally and lighter underneath. Their head are blue too, but the back and side are mottled. We will see blue whales as blue big thing in sea. Theres also 270-395 pairs of black, broad-based baleen plates each less than 3 feet long in their mouth. Blue whales’ stomach can keep 1 tonne of krills and need to eat about 4 tonnes of krill everyday. When they start eating, blue whales will expand their throat plates and takes in water and krills, pushes the water out through its baleen plates and swallowing the krills that already stayed in the mouth.
Blue whales can dive for about 10-20 minutes each time and not in really deep one, and its only about 100 metres. Blue whales can reach until 50 km/hour (31 mph) over short burst and 20 km/hour is their traveling speed. Based on Satellite Telemtry of Australian, pygmy blue whales which migrating to Indonesia can reach about 0,09 and 455,8 kilometres each day. Their speed also different when theyre feeding, because they will slow down into 5 km/hour (3,1 mph). Blue whales usually swim a depth about 13 metres (42,5 feet) when migrating and the deepest dive record as 506 metres (1,660 feet).
To get the krill, they always have move and they typically feed at depths more than 100 metres (330 feet) during the day and only surface-feed at night. Dive times while they feeding usually about 10 minutes, and can reach until 21 minutes whenever possible. Some sciencetist said that blue whales can live until 80 years old, but its kinda different since wahiling whales has start. Their longest age recorded as 34 years. Their natural predator is only orca and study reported that 25% mature blue whales will get scars because their fight with orca.
Mating and Baby Blue Whales
Blue whales prefer to deeper ocean waters than coastal waters. They migrate twice in whole year, which in the summer they looking for something to eat and they will go to cooler water.
Meanwhile in winter, they will back again to equator area because they need to breed and they need warmer water. Mating seasons usually start in late autumn and continues to the end of winter and in the autumn, male whales will start follow females one for prolonged periods of time.
Then, a second male will attempt to displace that first males and each other whales will start race at high speed, like between 17 miles/hour (27 km/h) to 20 miles/hour (32 km/h) in New Zealand. This racing often causes physical violence between the males and scientist already observed this behaviour in some part of the world, including Gulf of St. Lawrence in Canada and also in South Taranati Bight in New Zealand.
Mating and the birth of baby blue whales usually occured in fall and winter in the warmer Southern waters. Females usually give a birth every two or three years after their gestitation periods about 10 months and mostly of them are give a birth a single calf blue whales. Based from Marune Mammal Center States, a nurshing blue mother have to reproduces over 50 gallons of milk everyday to their baby. The milk contain 30-50% fat milk and thats why the baby can gain up until 10 pounds each hours and it means they will gain over 250 pounds each days!
As blue whales calf, they already identified as largest baby animal because their weight can reach until 4 tonnes and everyday they can gain weight until 90 kilograms instead they will be weaned after 7-8 months. When they already reach 15 metres length, its mean they already able to travel alone and do the normal migration. Blue whales calf will reach their sexual maturity at 5-10 years. Their growth rate identified as fastest one too because conception of weaning, which represents a several billion-fold increase in tissue just over a year and half.
Now a days, the inter-breeding interval is shorthen than when whaling occured, which means is a big possibility to increasing the growth rate of populations!
Habitat and Migration
Blue whales are found in all oceans in world wide, and theyre range widely from the coastal waters to the open ocean. Based on study by Southwest Fisheries Science Center (NOAA) in 1998, theres relationships between this species and habitat to concide movement its food source, like the migration due to its imperative for breeding.
Their primary habitat is thats based on feeding, and it was observed to be off shores of San Miguel and Santa Rosa island in the Channel Island and the adjacent continental shelf of the main land. In this place, blue whales can get lot of krills and another food source they really need. Theres additional habitat too for blue whales, which is for reproduction and usually take place in north Gulf of Cortez in Baja California and in the south of Central America.
Whales which belongin to the Atlantic population are frequently observed in shallow coastal zones where there so much krill which become primarily food of blue whales. The blue whales which live in Canada are seperated into two plates, some in North Atlantic and half one in North Pacific. During spring, summer, and fall those whales are occur along the North shore off the Gulf of St. Lawrence and off eastern Nota Scoatia. Meanwhile, it will easily found them between Baffin island and Greenland during summer. While in the winter, blue whales usually migrate to the south but they will stay in the St. Lawrence if theres so much snow that time and become years of light ice cover.
Blue whales classified into rarest types of whales too, beside now their population is about 10,000-25,000 individuals. We only can found like 2,000 blue whales in North Pacific off California. Even blue whales easily found in all oceans in the world, their populations had varied challenge, except in the North eastern Pacific (include Alaska down to Central America) population of blue whales is in dangerous situation and only in there the population is increase. This species therefore classified into A1 for endangered and it means critically endangered.
Theres no exactly how many population of blue whales which still live there, but they seen anually between 20-105 in the Gulf of St. Lawrence and total of 382 blue whales have been recorded in the Gulf since 1979. About 40% of them will return eventually while the remainder appear to be occasional visitors that typically outside of the St. Lawrence. Blue whales usually migrates in the small colonies and spending their summer in food-rich area close to the edge of polar ice, and while in winter they will stay in warmer temperature. They can eat krill (their primary food) like 4 tonnes each day for every blue whales!
Blue Whales Hunting and Its Conservation
Catch a blue whales isn’t really easy one because their speed and power. But its already different since 1864 when Svend Foyn use harpons to catch some blue whales, and its become success one also decrease blue whale population. Soon, blue whales hunting were start in another countries too, such as Iceland (1883), Nefaore island (1894), New found land (1898) and in Spits Bergen (1903).
In 1904-1905, first blue whales was taken off in South Georgia. Start at 1925, the hunting of blue whales increase dramatically and in the 1930 was recorded if some ships were caugh 29,400 blue whales in Antarctic. Asians also hunting blue whales, and they usually did that when blue whales migrates along western Japan to the east China Sea. Commercial catches were continued until 1965 and targeting blue whales usually catched in Hokkaido and Sanriku coasts.
Fortunately, blue whales hunting was banned in 1966 by International Whaling Commission because its already recorded there was 330,000 blue whales had been caught in Antartic; 33,000 in Southern Hemisphere; 8,200 in North Pacific, and 7,000 in North Atlantic. Since the whaling ban declared, its been reported that global blue whales is increasing and become stable population. The best increasing is in the Antartic, its been recorded increase 7,3% each year. While there, in various regionally like eastern North Pacific blue whales has rebounded too about 2,000 individuals and estimated about 97% for pre-hunting population.
The causes of this population decrease still reversible and understood. Even the population is abundant one, this population already decreased at least 70% and possibly as much 90% over three last generations. The main threat in the past was direct exploitation and its changed since human use harpoons canoons. Blue whale have been protected since 1966 but they still caught illegally by former until 1972. The last recorded deliberate catches were at Spain in 1978. Mean while, blue whales is subject to some ship strikes and entanglements. Because of their large size and have lot of bubbles, this species is often haunted by humans because they have high price and their body can be made into various materials.
During 1700’s a business largely due to growing industrial age and increasing using an oil combine with advances in technology and boating which make whales easily to hunt, kill, also captured and this lead to highly competitive whaling market then the whaling industry was born. The competition still continue because they got lot money from blue whales and they do that until near extinction.
Since its banned to haunt, The International Convention for The Regulation of Whaling have to monitoring and regulation of whale hunting increases in technology and cheap alternative resources provided companies and suppliers with alternative method of producing and selling their products without need to use whale oil as source of fuel or as an ingredients in their materials. Recently, we still can found this blue whales meat in some market at Japan even its labeled as another species.
The Endangered One
Therefore, there are about more than 250,000 blue whales in the world but recently (during 20th century) this species was nearly exterminated before have World Wide Protection in 1967. From 1904-1907, more than 350,000 blue whales were killed in Southern Hemisphere and another thousand blue whales also killed by Soviet during 1960s and 1970s.
While in 1931, during the heyday of whaling, there is like 29,000 blue whales were killed in Antarctic and its about 360,000 whales killed during the 20th Century.
People usually hunt them use faster boats and harpoon guns and in the 1960s this species was nearly extinct. Even its already decades from their protection of world wide, blue whales population isn’t increase yet from the commercial whaling and its estimated that world wide population of blue whales is only 1,200-3,000 and that’s why its identified as endangered one.
The blue whale was too swift and powerful for the 19th century whales to hunt but because invention of harpoon cannons, it become easier to catch blue whales. Blue whales killing reach a peak in 1931 when 29,649 blue whales were taken. In 1966, International Whaling Commission declared to protect blue whales in the world wide and now a days there still about 8,000-9,000 blue whales in the oceans and they considered as endangered one.
We can see them easily in the summer and fall in the California coasts, feeding in such places as the Gulf of Fordlones and Cordell Bank National Marine Sanctuaries. Based on IUCN, before whaling happened the largest population of blue whales was in the Antarctic, and it was approximately 239,000 individuals and smaller population in each of eastern North Pacific, Antartic, and Indian Ocean groups.
Right now, some factors like chemical pollutions, sound pollutions, habitat loss, overfishing of krill, ship strikes, and become entangled in fishing gears are things which make blue whales into endangered one. Climate change also have major impact to their food supply because global warming impact to krills populations. Another impact of global warming is blue whales’ frontal zone can be melted too and that means blue whales has to migrate further (like 200-500 km more) so they can reach food-rich areas and can sustain themselves for the rest of the year.
These longer migration path could increase the energy cost of migration and reduce duration of the main feeding season. As frontal zone moves further, they will move close together and reducing the over all area of foraging habitat which still exist.
So, thats some information about conservation of blue whales! Of course we don’t want them become extinct one, right? So you know what have to do know, like start the campaign to stop illegal hunting of blue whales or much easier: keep our marine environment clean! So, are you ready to make a change? Start it from yourself! 🙂