A fin whale surfacing (Photo: NMFS Southwest Fisheries Science Center)
The geologically-active Pacific Northwest has seismometers just about everywhere — on land, high-resolution arrays track what’s known as episodic tremor and slip. But researchers listen in underwater, too. Interestingly, a decade-old project to monitor tremors on the Juan de Fuca Ridge, an underwater volcanic mountain range, has generated a whale-science bonanza: recordings of more than 300,000 fin whale calls.
At story at UW News (“Using earthquake sensors to track endangered whales“) quotes principal investigator William Wilcock, a UW professor of oceanography, as saying the chattering whales “were kind of just a nuisance,” at least as far as seismographers were concerned. In 2008, having secured research funding, Wilcock turned his attention to the whales themselves. In a first, his team used software to work through the huge amount of data. With eight seismometers recording the calls, the whales’ position could be tracked throughout the area.
Researcher Dax Soule “created 154 individual fin whale paths and discovered three categories of vocalizing whales that swam south in winter and early spring of 2003.” Using Soule’s triangulations, Michelle Weirathmueller determined that the whales were making noises equivalent to a jet engine’s 130 decibels (actually 190 decibels underwater). The 17- to 35-hz pulses are just at the limit of human hearing for low notes.
Despite being the second-largest whale after the blue whale — they average 75 feet in length in the Northern hemisphere — the fin whale remains fairly mysterious. Preferring the open ocean, topping out at 23 mph, and capable of diving to 1,800 feet, they pose a challenge for study. Fin whales have been protected by the International Whaling Commission since 1966, but as the whales can reach up to 90 years of age, it’s likely that plenty of those remaining recall when tens of thousands of their number were slaughtered by commercial whalers each year.
These days, they’re still in danger from ships, even outside of Greenland, where they’re still hunted. They’re the whale most likely to collide with vessels, which is what experts suspect happened to the dead fin whale that washed up at Seahurst Park in Burien this April.
