Scientists report that fin whales can take in very large amounts of krill, but feeding efficiency can drop when krill accumulates on the whales’ baleen. Fin whales engulf dense swarms of krill—amounts cited in the research reach up to about 144 kilograms per mouthful—and then expel the water through baleen plates that act like filters. A study referenced by both outlets uses fluid-dynamics modelling and experiments designed to mimic conditions inside the mouth as krill builds up on the baleen. The findings indicate that a small fraction of the baleen must remain unobstructed: about 15% of the baleen needs to stay clear to allow water to flow out effectively. If krill clogging rises beyond that threshold, the expelled-water flow is reduced, which can slow or stall the filter-feeding process. The research uses frozen krill collected from retail sources to simulate how krill mass might accumulate during feeding. The authors say understanding the threshold for baleen clogging can inform conservation and management efforts for fin whales.