Mitochondrial DNA diversity of the Southwestern Atlantic humpback whale (Megaptera novaeangliae) breeding area off Brazil, and the potential connections to Antarctic feeding areas

Abstract

In the Southwestern Atlantic Ocean, humpback whales migrate every winter to the Brazilian coast for breeding and calving in the Abrolhos Bank. This breeding stock represents the remnants of a larger population heavily exploited during the beginning of the 20th century. Despite its relevance to conservation efforts, the degree of current genetic variation and the migratory relationship with Antarctic feeding areas for this population are still largely unknown. To examine these questions, we sequenced *400 bp of the mitochondrial DNA control region from samples taken off the Brazilian coast (n = 171) and near the Antarctic Peninsula (n = 77). The genetic variability of the Brazilian humpback whale breeding population was high and similar to that found in other Southern Hemisphere breeding grounds. Phylogenetic analysis suggested the existence of a new mitochondrial clade that exists at low frequency among Southern Hemisphere populations.Direct comparison between the Brazilian and the Colombia breeding populations and the Antarctic Peninsula feeding population showed no genetic differentiation between this feeding region and the Colombian breeding area or between feeding Areas I and II near the Antarctic Peninsula. In contrast, these populations were genetically distinct from the Brazilian population. Two humpback whales sampled off South Georgia Islands, in the Scotia Sea, shared identical haplotypes to whales from Brazil. Our results, supported by photo-identification and satellite telemetry data, suggest that the main feeding area of the Southern Hemisphere humpback whale population is likely to be located near the South Georgia/South Sandwich Islands area and not in the Antarctic Peninsula.

Population genetic structure of the South American Bryde's whale

“…For example common minke whale B. acutorostrata from both sides of the Japanese archipelago (Sea of Japan and western North Pacific) are genetically differentiated . Genetic differentiation between animals in the west and east coast of South America has also been reported for other species such as the South American sea lion Otaria flavescens (Artico et al 2010), humpback whale Megaptera novaeangliae (Engel et al 2008) and dusky dolphins Lagenorhynchus obscurus (Cassens et al 2003), which reveals a common phylogeographic pattern.…”

Unified Framework to Evaluate Panmixia and Migration Direction Among Multiple Sampling Locations

“…Example analysis of migration patterns among humpback whales sampling locations in the south seas: Olavarría et al (2007) and Engel et al (2008) described the interaction of several humpback whale populations (sampling locations). We use parts of their data to showcase how BF can inform the discussion of whether whales from these sampling locations belong to the same genetic population or not and whether some population models provide more appropriate descriptions than others.…”

“…Our analysis does not completely resolve the complex population interactions of humpback whales, but it shows ways in which our method is more useful than current methods for model comparisons. Engel et al(2008), using pairwise F ST estimates, suggested that Antarctic locations A1 and A2 appear panmictic; they used additional sighting data to suggest that the individuals sampled near the Brazilian coast probably do not move to the presumed feeding grounds in the Antarctic but instead aggregate at some unknown location. We chose a subset of models to investigate (1) whether the regions Antarctica 1 and 2 belong to a single population and (2) whether the Brazilian individuals and Antarctic individuals belong to the same population.…”

“…We compared two exponential and two uniform prior distributions: narrow uniform prior distribution for Q and M with a minimum of 0.00001, 0.0 and a maximum of 0.1, 5000, respectively; a wide uniform distribution with a maximum for Q and M of 0.5 and 50,000; a narrow exponential distribution with the same minimum and maximum as the narrow uniform but a mean of 0.01 and 100 for Q and M, respectively; and a wide exponential distribution with minimum and maximum of the wide uniform, but with a mean of 0.1 and 1000, respectively. Specific MIGRATE run conditions are described in File S1.Model selection: Model choice probabilities s i were calculated as suggested by Kass and Raftery (1995) byExample data set: Our example problem reanalyzes part of a data set of humpback whales from four sampling locations in the Southern Atlantic collected by Engel et al (2008): near Brazil, Antarctica 1 (west of the Antarctic peninsula), Antarctica 2 (east of the Antarctic peninsula), and Colombia ( Figure 1 in Engel et al 2008). The data were analyzed using several different migration models.…”

The waters of São Tomé: a calving ground for West African humpback whales?

“…Baker et al 1998, Smith et al 1999, Calambokidis et al 2001, Stevick et al 2003, Constantine et al 2007, Engel et al 2008). This was due to a lack of scientific research on whales in the region.…”