The Crisis of Antarctic Krill: Whales, Supertrawlers, and a Tipping Point

The blue whale is the largest animal to ever exist on Earth. Reaching weights of up to 200 tons, these massive creatures rely on a very specific diet. They eat almost nothing but krill. Krill are small, translucent crustaceans that look like tiny shrimp. They thrive in the freezing waters of the Southern Ocean near Antarctica. Blue whales are baleen feeders. Instead of teeth, they have plates made of keratin, the same protein found in human hair and nails. These plates act like a sieve or a giant strainer.

When a blue whale spots a large group of krill, it opens its mouth wide. The jaws have three hinges that allow the mouth to open extremely wide. The whale gulps in huge amounts of water and krill at the same time. It then pushes the water out through the baleen plates, trapping the krill inside. Only the blue whale eats krill as its main food source. An adult blue whale can eat up to 16 metric tons of krill in a single day. To put that in perspective, this is enough food to feed several hundred people.

However, this vital food supply is becoming less reliable. Climate change is warming the oceans and melting polar ice caps. These changes are causing major shifts in the krill population. Krill numbers are dropping in some areas by as much as 80 percent. Their behavior and location are changing as the water warms. Some parts of Antarctica are warming five times faster than the global average. In late 2022, the British Antarctic Survey warned that extreme changes in Antarctica were happening faster than scientists predicted. The continent may be approaching a critical tipping point. This makes the survival of the creatures that depend on krill even more uncertain.

Another serious threat to krill populations is human fishing. The dense swarms of krill in the Antarctic have attracted large industrial fishing vessels, known as supertrawlers. These ships can vacuum up to 1,000 tons of krill in one day. They process the catch onboard to make krill oil. This oil is rich in omega-3 fatty acids. It is used in human vitamin supplements, fish farm feed, and pet food.

The industry has grown rapidly over the last fifteen years. It is now worth up to $900 million each year. In October 2022, Norway began lobbying the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). This group manages the fishing rules for the region. Norway asked for the allowed catch limit to be doubled. The krill industry argues that they can harvest more without harm.