Genetic evidences of population decline in the harbour porpoise from Iberia waters over the last 30 years

Tjibbe Stelwagen (Speaker), Ben Chehida, H. (Speaker), Julie Thumloup (Speaker), Marisa Ferreira (Speaker), Fontaine, M. C. (Speaker)

Activiteit: Academic presentationAcademic

Description

Impact of climate changes on species is expected to be especially visible at the extremities of species distributions, where individuals meet sub-optimal conditions. The harbour porpoises (Phocoena phocoena) is a good model to test this prediction, especially the meridional populations. In the North-East Atlantic, the harbour porpoise inhabits the coastal waters as south as the upwelling waters of Mauritania and Iberia, where two isolated populations of a distinct ecotype have been recently described (P. p. meridionalis). Here, we have analysed changes in genetic diversity over the last 30 years in the semi-isolated population of Iberia. We screened the genetic variation of a quarter of the mitochondrial genome encompassing five genes (ATP-6, ATP-8, COI, ND5 and Cyt-b) for two cohorts sampled at different time: one composed of 60 individuals sampled between 2012 and 2015 and an historical one composed of 82 individuals including 19 from Iberia sampled between 1990 and 2002. Phylogenetic analyses revealed for the first time evidence of migration from the Mauritanian population into the present-day Iberian population, suggesting this latter is not as isolated as previously thought. No significant difference in haplotype frequency was found between the two cohorts (FST=-0.002NS), but we detected a significant decrease in all the estimators of genetic diversity once accounting for differences in sample size and migration. Consistently with this, Tajima’sDquantifying demographic trends showed negative values in both cohorts, with however a significantly less negative value in the contemporaneous cohort than in the historical
Periode9-apr-2018
Evenementstitel32nd Conference of the European Cetacean Society
: Marine conservation – Forging effective strategic partnerships
EvenementstypeConference
Conferentienummer32
LocatieLa Spezia, Italy
Mate van erkenningInternational