Beached Bones: Exploring the Genetic Impact of Exploitation on the Diversity of Great Whales in the South Atlantic

• Main Author: Sremba, Angela L.
• Other Authors: Baker, C. Scott, Henkel, Sarah, Liston, Aaron, Epps, Clint, Allendorf, Fred, Fisheries and Wildlife
• Format: Doctoral or Postdoctoral Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: Antarc*; Antarctic; Antarctic Peninsula; Blue whale
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/k3569917q

Commercial whaling during the 20th century drastically reduced many populations of great whales in the Southern Hemisphere. The Antarctic blue whale, for example, is estimated to have been reduced to less than 0.1% of its original abundance based on catch records and population dynamic models. Despite this population bottleneck, several contemporary populations of great whales are characterized by a relatively high mitochondrial DNA (mtDNA) diversity, potentially as a result of the long life span and the short duration of the exploitation bottleneck. However, few studies have attempted to compare historical diversity from artifacts of early commercial whaling to contemporary samples of living populations of whales. In this dissertation, I explored the impact of 20th century commercial whaling on the genetic diversity of great whales in the South Atlantic, using bones from early whaling stations that operated around the Antarctic Peninsula and the South Atlantic island of South Georgia at the beginning of the 20th century. Over 200,000 whales were taken from these stations from 1904 to 1965. The number of most species in the vicinity of the former whaling stations still remains low today. In Chapter Two, I used ancient DNA methods to extract and amplify mtDNA control region sequences to identify the species of a collection of 94 whale bone samples from the Antarctic Peninsula and South Georgia. I successfully identified to species 67 of the 94 whale bones collected from 12 locations of former whaling stations; eight on the Antarctic Peninsula and four on South Georgia. The species composition of the bone collection from South Georgia and the Antarctic Peninsula was similar to the catch history of the early years of whaling in the Antarctic region, supporting my inference that these bones represent ‘pre-whaling’ diversity. I then added the sequences from the samples to a collection of 231 whale bones from a previous study to provide the largest collection to date of historical DNA from great whales. In Chapter ...