Baker 2012-2013 Research Update
MMI – Cetacean Conservation and Genetic Laboratory (CCGL), Coastal Oregon Marine Experiment Station and Department of Fisheries and Wildlife
C. Scott Baker, Professor; Beth Slikas, Postdoctoral Fellow (now with Marine Biological Laboratory, Woods Hole, MA); Debbie Steel, Faculty Research; Becca Hamner (PhD), Renee Gibb (PhD), Angie Sremba (PhD), Alana Alexander (PhD), Dori Dick (PhD, Geosciences), Sophie Pierszalowski (Msc); John McClung (MSc) graduate students; Ana Lúcia Cypriano de Souza (PhD), visiting graduate student, Pontifícia Universidade Católica do Rio Grande do Sul, Brazil
The Cetacean Conservation and Genetic Laboratory (CCGL) is committed to a greater understanding of the molecular ecology and conservation genetics of whales, dolphins, and porpoises around the world. Our research on large whales, beaked whales and dolphins is pursuing four inter-related themes:
- Reconstructing the past
- Assessing the present
- Conserving the future
- Discovering new species
Reconstructing the past of whales and whaling
To improve our understating of the impact of hunting on the abundance of whales and the ecological role of whales before human exploitation, the CCGL is contributing to a Comprehensive Assessment of humpback whales in the South Pacific (Oceania) and southern right whales around New Zealand. A Comprehensive Assessment seeks to bring together available data, including catch records and current abundance, to reconstruct the history of populations before, during, and after the cessation of whaling. By integrating genetic information on the minimum size of populations during exploitation (the Nmin), we have improved the fit of population dynamic models typically used by the International Whaling Commission (IWC). Results of this work were presented to the annual meetings of the Scientific Committee of the International Whaling Commission in Panama City, Panama (June 2012) and Jeju Island, Republic of Korea (June 2013).
As part of our efforts to reconstruct the history of whale populations, Angie Sremba (now enrolled in a PhD program) completed her study of modern genetic diversity of the critically endangered Antarctic blue whale using a collection of samples made available through the IWC. The results of this work, published in PLoS One, provide the first circumpolar description of population structure and a revised estimated of the minimum size of the population at the time of the “exploitation bottleneck” (Sremba et al. 2012).
Assessing the present status of great whale populations
To assess the present status of great whale populations, the CCGL is involved in three large-scale, collaborative studies. In the North Pacific, we are collaborating with the Structure of Populations, Levels of Abundance and Status of Humpbacks (SPLASH). To date, we have completed sequencing of the mtDNA control region and microsatellite genotypes for more than 2,600 individual humpback whales representing nine feeding grounds and eight breeding grounds in the North Pacific. These results were used extensively by the Biological Review Team, established to review the listing under the US Endangered Species Act and are currently under review for publication.
In the South Pacific, the population structure and migratory interchange of humpback whales is under investigation in collaboration with members of the South Pacific Whale Research Consortium and the Southern Ocean Research Partnership (SORP) with support of the Government of Australia and other contributing nations.
In collaboration with Ocean Alliance, Alana Alexander has now completed DNA profiling of more than 600 individual sperm whales using samples collected during the 5-year Voyage of the Odyssey. This will provide the first circumequatorial survey of population structure and genetic diversity in this charismatic species.
Over the last three years, Scott has also made important contribution to the oversight of the Implementation Review of the North Pacific minke whales, by the International Whaling Commission. Populations of minke whales in the western North Pacific are the target of Japan’s controversial scientific whaling program, and are taken in large numbers as ‘incidental bycatch’ by both Japan and Korea. The Implementation Review is intended to bring together information on this exploitation, with estimates of abundance and population structure to assess the potential catches that would be allowed under the IWC’s Revised Management Scheme. Much of Scott’s previous work on the genetic monitoring the sales sold in commercial markets of Japan and Korea was included in the Review.
Conserving the future of great whales and dolphins
With support form a Pew Marine Conservation Fellowship, Scott has helped coordinate a large-scale study of dolphin population in Oceania, in collaboration with members of the South Pacific Whale Research Consortium. Referred to as ‘A Pattern of Dolphins’ or aPOD, the study seeks to understand the degree of isolation and connectivity among communities of dolphins found around islands throughout this vast region. This has included surveys of dolphins around the Society Islands and Marquesas of French Polynesia and the main islands of Independent Samoa, regions where dolphins are protected from exploitation. In the Solomon Islands, Scott has worked with his former PhD student, Marc Oremus, to assess the impact of the live capture or Indo-pacific bottlenose dolphins and the recent resumption of the traditional ‘drive-kill’ of spotted and spinner dolphins. Both the recent live capture for international trade and the drive-kill for teeth used in dowry necklaces, have raised concerns about the potential for local decline of these species.
With funding from the Marine Mammal Commission, Becca Hamner has been continuing her PhD research on the endangered Hector’s and Maui’s dolphins endemic to the coastal waters of New Zealand. Using both mtDNA and a suite of microsatellite loci, Becca has confirmed the genetic distinctiveness of the critically endangered North Island Maui’s subspecies and the genetic isolation between the regions populations of Hector’s dolphins around the South Island. The results highlight the importance of maintaining corridors for the low levels of dispersal that maintain diversity in each regional population (Hamner et al. 2013).
Discovering new species
Finally, Scott has continued with his interest in using molecular methods to identify species of the rare and cryptic beaked whales. Using bones collected in the remote Gilbert Islands of the Republic of Kiribati, Scott and his colleagues were able to identify three species of beaked whales, all of which had been used for human consumption (Baker et al. 2013). One of these beaked whales appears to be a previously unrecognized species, with an unusual distribution near islands in the central Pacific and Indian Oceans. In another recent publication (Thompson et al. 2013), Scott and his colleagues at the University of Auckland, New Zealand, used molecular methods to identify the first complete specimen of what may be the world’s rarest whale, the ‘spade-tooth’ whale, know previously from only two partial skulls and a partial jaw and tooth.