Using state-of-the-art
satellite-monitored radio tags, Dr. Mate and his staff made some exciting
discoveries about the migratory pathways, critical habitats, and behaviors
of endangered great whales. Some of these findings have challenged beliefs
previously held by cetacean researchers. For instance, scientists thought
that humpback whales wintering in Hawaii migrated directly from Hawaii
to Southeast Alaska for summer feeding. But data analysis of humpback
whales tagged off Hawaii in February 2000, combined with earlier tracklines
from 1997-1999, revealed a surprising pattern: although some of the whales
did indeed head for SE Alaska, most went to the coast of British Columbia,
other parts of Alaska (such as the Aleutian Chain), and even the Kamchatka
Peninsula of Russia. The tracklines show the whales fanning out across
the entire North Pacific Rim. One tag transmitted information for 220
days.
Another surprising discovery emerged through research done on highly endangered northern right whales in July-August 2000. Dr. Mate and his team worked with these rare whales in the Bay of Fundy, using both implanted satellite tags and time depth recorders (a short-term, recoverable tag attached with suction cups). Analysis of the data from this field season showed that these whales migrate at a rate of three miles per hour and make regular dives to 100-160 meters, a depth that coincides with the highest concentration of their copepod prey. The most exciting aspect of this research was the fall migration of a female right whale, "Piper," whose tag transmitted for 126 days, allowing the group to track her movements from the Bay of Fundy to a calving ground off Georgia. Such tag longevity holds great promise for future identification of other wintering areas, which have remained a complete mystery to scientists so far. Piper's tag also allowed Dr. Mate's team to send near-realtime locations to the Early Warning System on the East Coast, which alerts shipping traffic to right whales in the shipping lanes. (Boat collisions account for nearly half of all injuries and deaths of this most endangered of all whales.)
In October, Dr. Mate and his team tagged 13 blue whales near the Farallon Islands off Central California. Four of the tagged whales traveled south to the Costa Rican Dome (an area of upwelling near the equator that is rich in food) and stayed there for the entire winter. Two of those tags were still transmitting in May 2001, and one of the tagged whales began migrating north in mid-May. If the tag continues to transmit, this will be the first complete, year-round migration cycle ever recorded for any whale.
While working with the blue whales in October, Dr. Mate and his group were filmed by a British Broadcasting crew headed by Sir David Attenborough. The resulting footage will be featured in two parts of a nine-part series called "Blue Planet," set to air this autumn on the Discovery Channel.
In cooperation with the University of California at Santa Cruz and the Universidad Autónoma de Baja California Sur, Dr. Mate tagged 11 fin whales in the Sea of Cortez during March 2001. Data from these tags is still being analyzed.
Graduate student Kate Stafford successfully defended her doctoral dissertation (on determining the seasonal occurrence of blue whales throughout the Pacific Basin using acoustic information) in May. Dr. Stafford has now accepted a post-doctoral fellowship with the National Marine Mammal Lab in Seattle, Washington. Graduate student Mark Baumgartner worked on the data analysis from the July-August 2000 right whale research, revealing right whale dive depths and prey associations. He plans another field season in the North Atlantic during the summer of 2001. Daniel Palacios continues to analyze data from surveys he conducted in 2000 around the Galapagos Islands, to examine how oceanography affects the distribution and abundance of marine mammals in the Eastern Tropical Pacific. Daniel hopes to complete his doctorate by summer 2002.
