Over the years there have been a number of estimated guesses about the number of whales to be found in different areas of the oceans, but these varied tremendously and were often inaccurate.
In 2017, the International Whaling Commission (IWC) established a new group of experts to work on its range of estimates, which are known as ‘abundance estimates’. These estimates are based on data and feedback from a variety of sources including computer modelling, aerial sightings, acoustic monitoring and plenty of fieldwork. The role of the group of experts is to ensure the quality and consistency across all estimates used by the IWC. Their work ‘Population Abundance Estimates’.(https://iwc.int/estimate) makes interesting reading’.
Although the numbers of different whales sound large, they are a fraction of the total number of whales in the oceans before commercial whaling. Here the World Wildlife Fund (WWF) explains the importance of having whales in our oceans-
‘Whales are at the top of the food chain and have an important role in the overall health of the marine environment. Whales play a significant role in capturing carbon from the atmosphere; each great whale sequesters an estimated 33 tons of CO2 on average, thus playing their part in the fight against climate change.
Unfortunately, their large size and mythical aura does not protect them; six out of the 13 great whale species are classified as endangered or vulnerable, even after decades of protection. An estimated minimum of 300,000 whales and dolphins are killed each year as a result of fisheries bycatch, while others succumb to a myriad of threats including shipping and habitat loss’.
What is the forecast?
Unfortunately, the slaughter of thousands of whales between the 19th and 20th centuries has left the numbers of whales shockingly low. Since the International Whaling Commission (IWC) moratorium in 1986, all major countries except Norway and Japan have stopped commercial whaling and the number of whales is starting to increase. This will take a long time as whales mature slowly and reproduce slowly. They face other dangers including shipping strikes, entanglement in fishing gear and the greatest of all – global warming.
An article in Discover Magazine gives reason for quiet optimism –
‘In the late 1950s, only 440 humpback whales — or 1.6 percent of their one time number — were swimming around the south-western Atlantic Ocean. Thanks to whaling restrictions, these school bus-sized aquatic mammals have started to come back.
Now, a new paper estimates that the western South Atlantic whales have recovered even better than scientists previously thought. The massive cetaceans are 93 percent of the way to their pre-hunting population levels, the researchers say’.
Certainly, if this is the case, it is proof that despite the huge damage that humans inflicted on nature, that it can recover. As Alexandre Zerbini, co-author of the Royal Society Open Science paper and marine mammals researcher explains-
“It’s good to know that even though we as human beings almost killed them all, that once we left them alone, they grew back,”
Interestingly, in a report by the IWC made in the mid-2000s, scientists reckoned that the number of humpbacks had only increased to 50% of their original number. Zerbini and his colleagues, believe that the peak population for the humpbacks was in 1830, when there was between 23,000 and 34,000 whales. In sharp contrast, at the height of commercial whaling in the south-western ocean (from the mid 19th century till the 1940s), hunters killed between 20-40,000 humpback whales and tragically, these figures included many calves who were left orphaned when their mothers were slaughtered.
The optimistic news is that now the humpback whales are no longer hunted, there are about 25,000 in the region today. Provided the number of ship strikes and entanglements with fishing gear are kept to a minimum, the humpback population could reach 99% of its original level by the year 2030.
The success of the numbers of humpback whales is very encouraging, but the humpback is only one species and many others are not faring so well. One of these in the minke whale- a species that is still hunted in both Norway and Japan. The minke whale is an abundant species but it is the target for the whaling industry that continues today and its numbers are being badly depleted. The North Atlantic Right is in grave danger of disappearing totally as it is believed that there are only 400 whales now left and its home is in an area with numerous busy shipping lanes. https://www.fisheries.noaa.gov/ species/ north-atlantic-right-whale
There were originally 200 – 300,000 blue whales in the world and these huge marine mammals regularly live to 80-90 years. The blue whales is not only the largest whale but also the largest animal to ever have existed. Many were killed during the many years of commercial whaling and in 2002, it was calculated that there were 5,000-12,000 blue whales left. A more recent survey in 2012, came to the same conclusion, so the blue remains an endangered species.( https://www.quora.com/How-many-whales-are-left-in-the-world) Likewise, the number of sperm whales is still very low. Before commercial whaling, there were an estimated 1.1 million sperm whales and today there is a population of just 300,000 -400,000.https://www.fisheries.noaa.gov/species/sperm-whale
Another modest success story is that of the grey whale that was once found in three distinct areas – the North Atlantic, Korea and the eastern North Pacific. By the beginning of the 20th century, the population in the Western North Pacific looked as though it was facing extinction as sightings of it had become so rare and its numbers remain depleted. In a survey conducted in 2018, however clear evidence has indicated that the population is now increasing significantly near the island of Sakhalin (Korea) and also a significant number in the eastern North Pacific. https://www.maritime-executive.com/article/whale-conservation-success-highlighted-in-iucn-red-list-update
The recovery of the different species of whales is varied, but is essential as whales play an important role in balancing the marine environment in the oceans and a crucial role in trying to reverse climate change.