Study shows how blue whales maintain size

According to a recent study conducted by scientists from Stanford University, Oregon State University and National Oceanic and Atmospheric Administration (NOAA) Fisheries, blue whales employ specialized foraging strategies to reach and maintain their gigantic size.

This discovery, published in Science Magazine’s latest issue, counters previous perceptions of blue whales as “indiscriminate grazers” and shows that the world’s biggest creatures pay particular attention to prey density and depth to maximize efficient use of energy.

An average blue whale is 75 to 80 feet long and weighs around 110 tons, making it the largest animal in the world, according to Nature World Report, and some can even weigh as much as 150 tons. The main source of nutrition for blue whales to maintain their enormous size is krill, a tiny crustacean that lives in the oceans and that measures less than an inch. Every day the blue whale consumes 40 million krill, amounting to 8,000 pounds of prey, which it captures using a specific technique called “lunge-feeding.”

“For blue whales, one of our main questions has been, ‘How do they eat efficiently to support that massive body size?’” Elliott Lee Hazen, NOAA researcher and lead author of the study, told Nature World Report.

He noted that their study showed how blue whales optimized their feeding behavior and managed to control their energy use depending on where food is most densely present. Therefore, they make “the most of the food available,” he added.

Researchers explained that when prey density is low, blue whales minimize their oxygen use by their lowering feeding rate and energy intake; when prey density is high, they maximize feeding activity and energy intake. Through this sophisticated foraging behavior, blue whales are able to preserve their massive magnitude, research showed.

“They have a strategy that aims to focus feeding effort on the densest, highest-quality krill patches,” said Jeremy Goldbogen, researcher from Stanford’s Hopkins Marine Station and co-author of the study.

Although whales spend high amounts of energy to feed when they find high densities of prey, Goldbogen explained how the creatures balance the energy use.

“The increase in the amount of energy they get from increased krill consumption more than makes up for it,” he added.
Contact Sevde Kaldiroglu at sevde ‘at’ stanford.edu.