The study followed seven tagged baleen whales as they traveled in regions ranging from the Atlantic, Pacific, to Southern oceans. By using aerial drones, echosounders, and the tags, researchers were able to measure the density of krill in the baleen whale’s region as well as the daily and annual prey consumption of baleen whales.
Researchers were able to determine that previous studies vastly underestimated baleen whales’ consumption rates. The whales actually eat much more.
Prior to commercialized whaling, baleen whales were consuming 430 million tons of Antarctic krill per year. This is twice the current size of today’s Antarctic krill population and more than twice the size of marine fisheries’ annual global catch.
Baleen whales play a large role in global ecosystems, especially in their fecal matter. They essentially act as krill processing plants and disperse nutrients locked inside the krill back into the ocean ecosystem. The realization that baleen whales actually consume so much more than originally anticipated resoundly echoes the cries of conservationists for why we need to save the whales.
What Are Antarctic Krill?
Antarctic krill are the most densely populated animal species on Earth. Their total biomass is between 125 million and 750 million metric tons. These creatures are small and look like the more commonly known crawfish.
Antarctic krill stretch from the Antarctic continent to the polar front. They swim in dense schools and are hunted by a variety of other species. Most large whale species, leopard seals, some species of penguins, albatross, other fish, and even squid prey on this species of krill.
Basically, Antarctic krill are the main dish of marine life.
Even after being digested, Antarctic krill continue to feed the ocean. Inside krill are nutrients such as iron that help feed phytoplankton that are the base of the ocean’s ecologic food web. Phytoplankton are food for the krill and need the iron to survive.
Antarctic krill are one of the key middlemen of the marine food chain. Without them or their consumption, everything else would eventually die off.
Why Do Baleen Whale Diets Matter?
This study extrapolates on the data researchers found to determine the consumption rates of baleen whales prior to commercial whaling.
Industrial whaling has removed 80% of whales in the Southern Ocean in just 60 years. This has reduced baleen whale populations by 90%. This shows that with larger whale populations, marine ecosystems are far more productive.
The marine ecosystem is a cycle where whales, krill, and phytoplankton are the key players: Antarctic krill feed the whales; the whales poop out the nutrients needed for phytoplankton; the phytoplankton feed the krill; ultimately, the other marine species rely on these three functioning in order to survive.
By showing the importance of baleen whales in productive marine ecosystems, this study once again highlights the importance of rebuilding whale populations. If we support our world’s whales, we will ultimately benefit the entire ecosystem’s health and functionality.
The photo featured at the top of this post is © iStock.com/MR1805
Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.
- , Available here: https://www.nature.com/articles/s41586-021-03991-5
- , Available here: https://www.antarctica.gov.au/about-antarctica/animals/krill/
- , Available here: https://twitter.com/djshearwater/status/1455955428462891012?s=21