The magnificent blue whales are the largest known animal on Earth, weighing up to 400K pounds and reaching almost 100 feet in length. When blue whales migrate, it can lead to dangerous collisions with ships. Stanford University scientists set out to find a solution to prevent these collisions. They planted an underwater microphone, known as a hydrophone, outside of Monterey Bay in California and recorded whale vocalizations for more than five years.
The team found a distinct change in the blue whale’s song before its annual migration south. Keeping an ear out for these changes could help warn ship operators in the location of an upcoming migration.
They also observed fifteen singing whales’ behavior by sticking tags on the mammal’s backs, containing pressure sensors, GPS trackers, and accelerometers, which distinguishes fine-scale vibrations that occur when a whale is singing.
Blue whales spend their summers in the Pacific Ocean’s northeast region, and in Autumn, they migrate to the coast of Central America, where they breed and relax in the cold weather. The team discovered that the whales sing during the night, but before their migration begins, they switch to a daytime tune.
William Oestreich, the study’s co-author and a biologist at Stanford, said:
There is a near real-time signal of what these animals are doing out in a habitat that’s historically been really difficult to observe.
Both female and male whales sing, but the male is well known for its loud, long, and intricate melodies. Females and males have been spotted meeting up and feeding together shortly before their migration departure. Both sexes move southward at around the same time every year. “That gives us some confidence that the sounds that are primarily being produced by males are fairly representative of what the whole population is doing,” Oestreich added.
Receiving an advanced warning would prevent collisions, which can be destructive for boats while saving the lives of migrating whales.
Oestreich noted:
There has been quite a noticeable number of fatal collisions between ships and blue whales. That could be one piece of the puzzle to more dynamically manage those habitats and shipping lanes in a way that allows shipping to continue, but also in a way that is safe for these whale populations.
The Stanford team’s research was published on October 1, in the journal Current Biology.
