Presentation Detail

Population Genetics and/or Genomics, Empirical

Sremba, Angie [1], Martin, Anthony [2], Cypriano de Souza, Ana [3], Engel, Márcia [3], Bonatto , Sandro [3], Baker, C. Scott [4].

Beached bones: diversity and population differentiation of mtDNA from humpback whales killed at South Georgia whaling stations.

Historical bone samples have preserved the genetic diversity of pre-exploited populations and offer the opportunity to explore a potential loss of diversity due to exploitation of the humpback whale (Megaptera novaeangliae) around the South Atlantic island of South Georgia. Between 1904 and 1918, over 24,000 humpback whales were killed from the waters surrounding South Georgia, the first commercial whaling industry established in the Southern Hemisphere.Today, there is evidence of little return of humpback whales to South Georgian waters; the few whales that have returned have shown a migratory connection to the humpback whale breeding population off the coast of Brazil, Breeding Stock A (BSA). Here we present the largest study, to date, of pre- and post-whaling diversity and differentiation in populations of humpback whales. Using ancient DNA extraction methods and mitochondrial DNA (mtDNA) control region sequencing we identified to species 230 whale bones collected from South Georgia whaling stations. Among these, 158 bones were identified as humpback whale. These bones have captured the genetic diversity of the humpback whale population that once swam in the surrounding waters. To test for a loss of genetic diversity due to exploitation by the commercial whaling industry, we compared 278 bp of the mtDNA control region of the historic South Georgia sample to the contemporary BSA population (n=158). We re-sequenced and validated all unique mtDNA haplotypes in both the historic and contemporary populations to avoid bias in estimates of genetic diversity. Both populations showed a relatively high mtDNA haplotype diversity (SG h=0.962; BSA h=0.971). Although the contemporary population did not show a reduced haplotype diversity in comparison to the historic population, the two populations were significantly differentiated (F_ST=0.012,p<0.005). A comparison of the 64 historic South Georgia haplotypes to the 51 contemporary BSA haplotypes revealed only 22 shared between the two populations, suggesting a loss of a local feeding population from South Georgian waters. This is consistent with other observations of variable recovery due to loss of cultural traditions in migratory destinations.

1 - Oregon State University, Marine Mammal Institute, Department of Fisheries and Wildlife, 2030 SE Marine Science Drive, Newport, OR, 97365, USA
2 - University of Dundee, Nethergate, Dundee, DD1 4HN, Scotland, UK
3 - Pontifícia Universidade Católica do Rio Grande do Sul, Faculdade de Biociências, Avenida Ipiranga 6681, Porto Alegre, RS, Brazil
4 -

Keywords:
none specified

Presentation Type: Regular Oral Presentation
Session: 53
Location: Alpine A and B/Snowbird Center
Date: Sunday, June 23rd, 2013
Time: 9:00 AM
Number: 53003
Abstract ID:696
Candidate for Awards:W.D. Hamilton Award for Outstanding Student Presentation