The population of humpback whales has seen an amazing resurgence in the previous five decades. Global conservation efforts consider it among the most successful stories. So much so, that the federal Environment, Agriculture, and Water Department is thinking about removing them from the threatened list in Australia.
However, there are new threats emerging rapidly for humpback whales. Climate change is the most potent among them. Surveying the creatures is extremely difficult. Moreover, the government is not yet considering monitoring them, ensuring the population’s strength after being delisted.
A Range Of Threats Still Faces The Humpback Whales
Humpback whales are possibly the most well-recognized aquatic mammal. Every ocean has them, and their migration is among the longest.
Their numbers became extremely low due to commercial whaling. For Australia, whaling and exporting whale products was the nation’s primary industry. From 1949 till 1962, an estimated 8,300 humpback whales were killed. Only some hundreds remained.
Then, in 1963, humpback whaling was banned in the entire Southern Hemisphere. Since then, the population of the mammals on the eastern and western coast of Australia, have reached or even exceeded their original size. It is estimated that it grew by at least 10% annually in the previous decade. Presently the numbers stand at about 30,000 and 40,000 on the east and west Australian coast respectively.
However, there are new threats facing the mammal. These include climate change, marine degradation, discarded fishing gear, pollution, etc. Climate change is especially dangerous. Ocean acidification, warmer waters, and shifting currents may kill off humpback whales’ prey. Scientists estimate that, in the worst-case scenario, the population may become stagnant, or even shrink, in the coming 5 to 10 years.
Moreover, the resurgent population data is at least 5 years outdated since tracking them is extremely hard. These are all predictions that hardly account for the present major threats such as climate change. Recent studies, such as one in 2019, indicate that calving locations have shifted. In the Northern Pacific one, the rate of calving is decreasing as well.
Furthermore, the conditions that existed before whaling were vastly different than what they are now. Krill numbers are declining fast, which may be devastating for humpback whales. Nevertheless, even after being delisted, countries like the US have established monitoring plans lasting a decade. For Australia as well, researchers are pushing for one.