Where did the whales go? Or did they even do anywhere?

Humpback whales (Megaptera novaeangliae) can be found in all major oceans, which means that you don’t have to go far to get to see one of these beautiful creatures. In fact, you should try and see one while you still have the chance. The populations of humpback whales have been a concern since the 1950s when severe whaling decreased whale populations by 90%. Whales have been known to provide us with direct value through human consumption of meat and oil provided by whale blubber. As consumers we are driven to making a profit and unfortunately sometimes this comes with increased hunting with the consequences of losing species that are beneficial to our environment. A new ship based study has shown that the recent prediction of whale populations is much greater than originally thought due to implementation of whaling laws. You would think that with an increase in population the need for more conservation efforts would not be needed but even with an increase in numbers, the risk of other human threats also increases. This causes the need for other conservation efforts. Population studies allow us be aware of how many whales there are and where they live so that we can see the success of conservation efforts and figure out how to continue these efforts.

This study focused on a particular population of humpback whales, those in the Western South Atlantic, along the coast of Brazil. This population was on the “endangered list” as it was depleted to near extinction in mid-twentienth century. It wasn’t until 1960 that the International Whaling Commission warranted a protection of this species from human activities such as whaling. This protection allowed for the recovery of whales and a decade ago these whales were reclassified from ‘vulnerable’ to ‘least concern’ and are now only endangered in Arabian sea and the Oceania population.

The rise in humpback whale populations are excellent at the moment but there are still other threats present. While the whales are showing significant increase in populations since the protection act has been in place, there are other concerns that draw our attention back to monitoring the humpback whales. Whales have been recovering but along with this recovery is also an expansion in their range distribution. With whales swimming further from the coast then normal, it heightens the chance for conflicts with other anthropogenic activities. These conflicts can include things such as ship strikes, entanglements with fishing gear, and issues related to the oil and gas industry. By understanding the rate of whale population recovery and their distribution we can figure out a way to ensure that our human activity is not interfering with this recovery.

Population studies allow for an understanding of how a particular species population is growing. Most of the population survey studies done on whales have been done aerially. In a research paper by Bortolotto, et. Al, they also wanted to do a population study on the humpback whale population in WSA, except they took a different approach. Their aim was to present ship-based line-transect estimates of abundance for humpback whales. They did this by having two research cruises along the coast of Brazil in 2008 and 2012 so that they could investigate the changes in population size. Their study showed results of an increased number of whales than previous aerial studies.

Humpback whale populations were shown to increase 26.7% from 2008 to 2012. The study showed that there were 15,332 whales in 2008 and 19,429 whales in 2012. The numbers in 2012 are not completely accurate due to severe weather limited the observable study area.

Ship-based studies provide a different and perhaps more accurate estimate of species abundance than aerial studies. The abundance of whales before severe whaling occurred was around 25,000 whales in WSA. A previous aerial study in 2006 showed that the recovery of the hump back whale population would be 60% recovered by 2020 but the ship-based study shows that we already surpassed this. The whale population is already at 65% recovery. The results show that the recovery of humpback whales is occurring at a faster rate than shown by previous aerial studies predicted.

There are various methods that can be used for understanding the populations of different species and by performing various study methods it can give different insight to the dynamics of a population. Through monitoring the abundance of whales we can see not only the significant increase in humpback whale abundance over the years, but also the importance of continually monitoring the population. The projected population recovery made in 2006 is substantially different compared to the results provided by the 2008 and 2012 study.

Since the protection act of whales was enacted it has allowed for the increasing recovery of humpback whales. This shows the success of conservation efforts and protection acts. While whaling is now highly regulated, there are other anthropogenic factors that are not controlled. The threats of increased entanglements and ship strikes can be prevented by protecting the area where whales swim and breed. There is also an increased interest in oil and gas extraction in the WSA and according to Brazilian National Agency of Petroleum, Natural Gas and Biofuels, they plan on expanding. This would negatively affect the reproductive success of whales. These human activities still pose a threat to whales and with a population that has once been vulnerable to extinction it would be sad to see the whales head back in that direction. Population studies have allowed us to see the significantly fast increase of the whale population due to one conservation law so imagine what a few more laws could do to keep the whales from heading back towards extinction.