Lindsay A. Cooper
DUBLIN—Dr. Scott Baker, a pioneer in the use of DNA to better understand the population structure, abundance, and genetic diversity of dolphins and whales, spoke recently at University College Dublin about new research that could help shape conservation measures for North Pacific humpback whales.
Baker, associate director of the Marine Mammal Institute at Oregon State University and adjunct professor in the School of Biological Sciences, University of Auckland, New Zealand, was awarded a Pew marine fellowship in 2011 to study dolphin populations in the western Pacific. His fellowship project is part of a much larger body of work that uses genetic analysis to help conserve marine mammals.
Commercial hunting of whales before 1966 significantly depleted the world’s whale populations. Researchers studying highly migratory, and sometimes isolated, marine mammals face great challenges as they work to learn if and how these populations are recovering. But genetic fingerprints are helping scientists such as Baker learn important information about many species, particularly those that don’t appear to be recovering from whaling as well as experts think they should be.
Approximately 26,000 humpbacks were killed before 1966, when the International Whaling Commission banned commercial hunting of these large whales. Baker noted that the oceanic population of the North Pacific humpback probably had fallen to fewer than 1,000 at the time. By 1973, it was listed as endangered under the U.S. Endangered Species Act, which finally protected it from hunting.
Populations are recovering—scientists estimate there are now more than 21,000 humpbacks in the North Pacific, and the listing status is likely to change. But a fuller understanding of the subsets of these whales will help tailor continued protective measures where needed. Baker said an astounding amount of information can be gathered by combining traditional photo identification techniques and DNA profiling.
During his presentation, Baker described a soon-to-be-published paper resulting from work done for SPLASH, the Structure of Populations, Levels of Abundance and Status of Humpback Whales in the North Pacific, one of the largest international collaborative studies conducted of any whale population. Using 2,193 genetic samples collected from North Pacific humpbacks in 10 feeding regions and eight breeding areas, Baker and colleagues documented complex patterns of migration.
The researchers found that some groups of whales return exclusively to the same feeding and breeding grounds each year. As a result, some humpbacks in the North Pacific are completely isolated from other groups, though no physical barriers prevent them from moving elsewhere. This information can then be used to illustrate the number of “distinct population segments” for listing under the U.S. Endangered Species Act.
Baker also introduced a cloud-based database to support the integrated catalogue of photo-identification records and DNA profiles. Photo-ID records or DNA profiles for more than 8,000 whales are included in the database.
Baker’s work represents major advances in the application of genetic analysis to achieve a better understanding of the biology and behavior of marine mammals. The results of the North Pacific humpback whale study could have important implications for the current status review of humpback whales as mandated under the U.S. Endangered Species Act.
Bonus: Check out this short video of Baker discussing his research and his involvement in the well-known documentary “The Cove.”
Lindsay A. Cooper works with the Pew Fellows Program in Marine Conservation. Cooper was in Dublin, Ireland, with Baker and other Pew marine fellows for the program’s annual meeting.