German scientists from the Institute for Marine Research in Bremerhaven and the University of Hamburg could not believe their eyes when, on an expedition two years ago, they discovered a group of 150 fin whales in the Antarctic Sea off Elephant Island, Antarctica. 150 huge whales feed on plankton together.
A vision unprecedented in our time. Such groups of fin whales must have been common previously, since the seas around Antarctica were important habitats for the fin whale. But that was more than a century ago.
In the early 20th century, whaling in the Antarctic Sea gained steam and continued until the fin whale quota was set to zero in 1976, ten years before the general moratorium on whaling. An estimated 700,000 fin whales were hunted in the Antarctic during those three quarters of a century, and the number of these large whales in the area has been reduced to 1 percent of their original size. The fin whale has practically disappeared from its historical habitat.
The population is recovering
Ending the chase did not immediately lead to a return. In the first period after the ban on whaling, fin whales were hardly seen around Antarctica. Now, more than forty years later, it’s different, German researchers write in a professional journal Scientific Reports† They thus confirm occasional observations (of groups) of fin whales that have been made since the turn of the century.
The researchers say these observations are in line with the trend: The fin whale is back in Antarctica. They have searched for whales on several helicopter flights in recent years. The researchers say it’s not systematic enough to come up with very accurate estimates of the numbers, but it’s enough to say that fin whales in Antarctica are recovering.
At the top of the list of fin whales is the krill, the plankton shrimp. And in previous research, biologists estimated how much krill should be consumed by the indigenous population of fin whales, pre-hunting, in Antarctica: 430 million tons annually. This is twice the number of krill currently found in the Antarctic Sea.
Good news for the climate
You might think: if a whale is caught, then the plankton crustacean dances on the table, but this is not the case. Whales eat a lot of plankton, but they also defecate a lot. Especially the nutrients on which phytoplankton can grow, plant organisms, like plants, that use sunlight and carbon dioxide.2 making their own building materials. These phytoplankton are food for krill, which in turn is food for the whale.
The whales in this story are actually huge pumps that keep the cycle going. If these pumps were removed, there would be no more plankton, but fewer. German researchers say that’s exactly what happened in the Antarctic Sea. But now that the fin whales are back, the cycle can start again and the plankton can start growing again. Since then, the Phytoplankton Company2 Eat, this is also good news for the climate.
Read also:
Swimming for at least 20,000 km, how do gray whales do it?
Paleontologist Jill Roemer explains it.
