Female philopatry in coastal basins and male dispersion across the North Atlantic in a highly mobile marine species, the sperm whale (Physeter macrocephalus)

Authors


  • All authors contribute to a better understanding of the population biology, behaviour, ecology and conservation needs of marine mammal species. Dan Engelhaupt undertook the laboratory work and analyses as a part of his PhD studies, supervised by Rus Hoelzel and with the assistance of technician Colin Nicholson. Work in the Molecular Ecology Group at Durham focuses on understanding the processes that govern the evolution of genetic diversity among and within natural populations in both marine and terrestrial environments.

A. Rus Hoelzel, Fax: +44 (0) 191 334 1201; E-mail: a.r.hoelzel@durham.ac.uk

Abstract

The mechanisms that determine population structure in highly mobile marine species are poorly understood, but useful towards understanding the evolution of diversity, and essential for effective conservation and management. In this study, we compare putative sperm whale populations located in the Gulf of Mexico, western North Atlantic, Mediterranean Sea and North Sea using mtDNA control region sequence data and 16 polymorphic microsatellite loci. The Gulf of Mexico, western North Atlantic and North Sea populations each possessed similar low levels of haplotype and nucleotide diversity at the mtDNA locus, while the Mediterranean Sea population showed no detectable mtDNA diversity. Mitochondrial DNA results showed significant differentiation between all populations, while microsatellites showed significant differentiation only for comparisons with the Mediterranean Sea, and at a much lower level than seen for mtDNA. Samples from either side of the North Atlantic in coastal waters showed no differentiation for mtDNA, while North Atlantic samples from just outside the Gulf of Mexico (the western North Atlantic sample) were highly differentiated from samples within the Gulf at this locus. Our analyses indicate a previously unknown fidelity of females to coastal basins either side of the North Atlantic, and suggest the movement of males among these populations for breeding.

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