Mitochondrial DNA Diversity and Population Structure among Southern Right Whales (Eubalaena australis)

Abstract

The population structure and mitochondrial (mt) DNA diversity of southern right whales (Eubalaena australis) are described from 146 individuals sampled on 4 winter calving grounds (Argentina, South Africa, Western Australia, and the New Zealand sub-Antarctic) and 2 summer feeding grounds (South Georgia and south of Western Australia). Based on a consensus region of 275 base pairs of the mtDNA control region, 37 variable sites defined 37 unique haplotypes, of which only one was shared between regional samples of the Indo-Pacific and South Atlantic Oceans. Phylogenetic reconstruction of the southern right whale haplotypes revealed 2 distinct clades that differed significantly in frequencies between oceans. An analysis of molecular variance confirmed significant overall differentiation among the 4 calving grounds at both the haplotype and the nucleotype levels (F(ST) = 0.159; Phi(ST) = 0.238; P < 0.001). Haplotype diversity was significantly lower in the Indo-Pacific (h = 0.701 +/- 0.037) compared with the South Atlantic (h = 0.948 +/- 0.013), despite a longer history of exploitation and larger catches in the South Atlantic. In fact, the haplotype diversity in the Indo-Pacific basin was similar to that of the North Atlantic right whale that currently numbers about 300 animals. Multidimensional scaling of genetic differentiation suggests that gene flow occurred primarily between adjacent calving grounds within an ocean basin, with mixing of lineages from different calving grounds occurring on feeding grounds.

Population structure and individual movement of southern right whales around New Zealand and Australia

“…Haplotypes were identified from a 275 bp consensus region with haplotype codes established by Patenaude et al (2007), with revisions described in Tables S1 & S2 in the supplement at www.int-res.com/articles/suppl/m432p257_supp. pdf.…”

“…These areas are poorly described, but are known to include an area south of Western Australia (114 to 123°E and at least 60°S; Bannister et al 1999). There is some evidence from the analyses of mitochondrial DNA (mtDNA) data that whales from distinct calving grounds intermix on these feeding grounds (Baker et al 1999, Patenaude et al 2007.…”

“…Previous genetic studies have shown evidence of population structure on calving grounds based on differences in mtDNA haplotype frequencies between southwest Australia, NZSA, Ar gen tina and South Africa (overall F ST = 0.159; Patenaude et al 2007). Those authors attributed this genetic differentiation to maternal fidelity to calving grounds, a conclusion supported by behavioural data from long-term studies in South Africa, Argentina and southwest Australia (Best et al 2001, 2005, Burnell 2001, Cooke et al 2001, Patenaude et al 2007.…”

Factors affecting whale detection from large ships in Alaska with implications for whale avoidance

“…Some whale populations are in recovery (e.g. Patenaude et al 2007) or potentially fully recovered from pre-whaling abundances (Monnahan et al 2015), and thus may be able to sustain these added mortality events. Others remain at reduced abundance levels where even small increases in anthropogeniccaused mortality threatens population persistence (Kraus et al 2005, LeDuc et al 2012.…”

“…Coincident with increased ship traffic has been a growing concern over the deleterious impacts shipping may have on populations of large whales, which continue to recover from near extirpation (e.g. Patenaude et al 2007, Magera et al 2013, Monnahan et al 2014 following intensive unreported or unregulated levels of whaling (Ivashchenko et al 2013, Carroll et al 2014). For example, primary feeding areas, calving and breeding grounds, and migration routes of North Atlantic right (Eubalaena glacialis), humpback (Megaptera novaeangliae), and fin whales (Balaenoptera physalus) overlap with highly trafficked shipping routes to major ports along the western North Atlantic, resulting in a number of lethal ship−whale collisions each year (Vanderlaan et al 2008, Conn & Silber 2013.…”