Rise of oceanographic barriers in continuous populations of a cetacean: the genetic structure of harbour porpoises in Old World waters

Abstract

Background: Understanding the role of seascape in shaping genetic and demographic population structure is highly challenging for marine pelagic species such as cetaceans for which there is generally little evidence of what could effectively restrict their dispersal. In the present work, we applied a combination of recent individual-based landscape genetic approaches to investigate the population genetic structure of a highly mobile extensive range cetacean, the harbour porpoise in the eastern North Atlantic, with regards to oceanographic characteristics that could constrain its dispersal.

History of expansion and anthropogenic collapse in a top marine predator of the Black Sea estimated from genetic data

“…Genotypes at 10 microsatellite loci from the same 78 porpoises from the Black Sea were taken from the study by Fontaine et al (24), to which we added 11 newly genotyped porpoises from the Aegean Sea (Fig. 1), following the genotyping procedure described by Fontaine et al (24,57). Genetic polymorphism at each locus was quantified using the allelic richness (A r ), the observed and unbiased expected heterozygosity (H o and H e ), and the fixation index (F IS ).…”

“…An important assumption of these models is that the study population is isolated, such that changes in genetic diversity over time will only reflect changes in local effective population size (i.e., mainly change in the number of reproducing individuals) (23). For the three small cetaceans of the Black Sea, this assumption is likely only to be met by the harbor porpoise, which is both geographically and genetically isolated from the North Atlantic populations by the Mediterranean Sea (24)(25)(26). This isolated status has been the basis for recognizing the Black Sea harbor porpoise as a subspecies (P. phocoena relicta) distinct from the Atlantic subspecies (P. phocoena phocoena) (25), and it has also been instrumental to the species' current listing as endangered by the International Union for Conservation of Nature (15).…”

Occurrence of anthropogenic and naturally-produced organohalogenated compounds in tissues of Black Sea harbour porpoises

“…The Black Sea acts as a sink for chemicals as it receives high loads of pollutants through run-off from the surrounding countries and because it is linked to the Mediterranean Sea only through the Marmara Sea (Tanabe et al, 1997a). As a consequence, porpoises from the Black Sea are isolated from their counterparts in other European waters, migrate only on a small scale and spend their entire life in the same area (Fontaine et al, 2007;Viaud-Martinez et al, 2007).…”

Does temporal and spatial segregation explain the complex population structure of humpback whales on the coast of West Africa?

“…Information on the spatial and temporal patterns of population structure can improve our understanding of underlying intrinsic and extrinsic processes (e.g. Palsbøll et al 2004;Fontaine et al 2007). …”