The Marine Mammal Institute's Whale Telemetry Group (WTG) has pioneered the development of satellite-monitored radio tags to study the movements, critical habitats, and dive characteristics of free-ranging whales and dolphins around the world. Since the first deployment of a satellite tag on a humpback whale off Newfoundland, Canada, in 1986, the WTG has tagged a total of 462 whales from 11 different species. This work has led to the discovery of previously unknown migration routes and seasonal distribution (wintering and summering areas), as well as descriptions of diving behavior.
The WTG primarily focuses on endangered whale species whose distribution, movements, and critical habitats (feeding, breeding, and migration areas) are unknown for much of the year. Decision makers use this valuable information to manage human activities that may jeopardize the recovery of endangered whale populations.
The objectives of the WTG’s telemetry studies are to: (1) identify whale migration routes; (2) identify specific feeding and breeding grounds, if unknown; (3) characterize local whale movements and dive habits in both feeding and breeding grounds, and during migration; (4) examine the relationships between whale movements/dive habits and prey distribution, time of day, geographic location, or physical and biological oceanographic conditions; (5) provide surfacing-rate information that can be useful in the development of more accurate abundance estimations, or assessing whales’ reactions to human disturbance; (6) characterize whale vocalizations; and (7) characterize sound pressure levels to which whales are exposed.
A team of scientists from the United States and Russia has documented the longest migration of a mammal ever recorded – a round-trip trek of nearly 14,000 miles by a whale identified as a critically endangered species that raises questions about its status. The researchers used satellite-monitored tags to track three western North Pacific gray whales from their primary feeding ground off Russia’s Sakhalin Island across the Pacific Ocean and down the West Coast of the United States to Baja, Mexico. One of the tagged whales, dubbed Varvara, visited the three major breeding areas for eastern gray whales, which are found off North America and are not endangered. Results of their study are being published this week by the Royal Society in the journal Biology Letters.
Every spring for almost thirty years, Bruce Mate makes his way down to Baja to reconnect with the same female gray whales. Over four decades, he’s witnessed their transition from smooth-skinned youth into mothers. More recently, he’s seen wrinkles start to appear around some of their eyes, each eye roughly the size of a baseball. He’s met and played with their offspring, even seeing some from the next generation become mothers themselves. These whales feel like family to him.
A new paper by Ladd Irvine and other MMI researchers finds that the favored feeding areas of endangered blue whales along the US West Coast are crossed by heavily used shipping lanes. The paper, which was published today in PLoS ONE, notes that moving the shipping lanes off Los Angeles and San Francisco slightly could significantly decrease the probability of ships striking the whales. The analysis is the most comprehensive study of blue whales' movements ever conducted.