Long-finned pilot whale population diversity and structure in Atlantic waters assessed through biogeochemical and genetic markers

Abstract

The integration of ecological and genetic approaches is a particularly powerful strategy to identify natural population structure and to obtain information on foraging habitat and habits and social structure, over different timescales. In order to investigate the potential occurrence of population segregation in long-finned pilot whales (Globicephala melas) in the North Atlantic, both biogeochemical (fatty acids and stable isotopes) and genetic (mitochondrial DNA) markers were analyzed in animals from four areas within the North Atlantic: Northwestern Iberian Peninsula, United Kingdom, Faroe Islands and United Sates of America. The genetic data revealed strong oceanic and regional levels of divergence, although AMOVA revealed no differentiation between East and West Atlantic. Results from biogeochemical tracers supported previous dietary studies, revealing geographic and ontogenetic dietary variation in G. melas. These results suggest that both ecological and genetic factors may drive the levels of pilot whale differentiation in the North Atlantic. The ecological segregation observed may be related with the exploitation of different foraging niches (e.g. oceanic vs. coastal), which can be highly influenced by prey distributions and/or oceanographic phenomena. Genetic differentiation may result from limited dispersal mediated through the social structure presented by this species. These results from multiple approaches provide preliminary information about pilot whale stocks in the North 2 Atlantic, based on both evolutionary and finer ecological timescales, essential baseline information for conservation and management plans.

Complex biogeographical patterns support an ecological connectivity network of a large marine predator in the north‐east Atlantic

“…Ecological spatial structuring has been also suggested for other delphinid populations occupying large areas, that is, over hundreds or thousands of kilometres. Examples include populations of long‐finned pilot whales ( Globicephala melas ) in the north Atlantic (Monteiro et al., ), of killer whales ( Orcinus orca ) in the north‐east of the Pacific and the Atlantic (Dahlheim et al., ; Foote, Similä, Víkingsson, & Stevick, ), of bottlenose dolphins ( Tursiops truncatus ) in northern Atlantic and Pacific archipelagos and in the Mediterranean (Baird et al., ; Bearzi, Bonizzoni, & Gonzalvo, ; Silva et al., ; Tobeña et al., ) and of false killer whales in Hawai'i (Baird et al., ).…”

New haplotypes found in stranded long‐finned pilot whales (Globicephala melas) in the eastern North Atlantic and adjacent waters

“…Across the Southern Hemisphere, 13 of the known 17 345 bp mtDNA CR haplotypes have been recorded (Kraft et al, 2020;Oremus et al, 2009). Only seven of the 17 345 bp mtDNA CR haplotypes have been recorded in the North Atlantic, of which four are not shared with the Southern Hemisphere (Monteiro et al, 2015;Oremus et al, 2009;Sabatier et al, 2015;Siemann, 1994). Within the North Atlantic, the United Kingdom (UK) was identified as the region with the highest number of 345 bp mtDNA CR haplotypes (n = 5) (Monteiro et al, 2015).…”

“…However, the sample sizes from the three studies that included the UK were limited (Monteiro et al, 2015;Oremus et al, 2009;Siemann, 1994) and they did not include the unusual individuals stranded in the Netherlands or samples from Ireland, which is an understudied coastline of the eastern North Atlantic.…”

DNA preserved in jetsam whale ambergris

“…However, other marine mammal species (e.g. members of Globicephala and Ziphiidae) also predate on squid [9][10][11], and some (including dwarf and pygmy sperm whales) are also cited as potential sources of ambergris [4]. Therefore, to further elucidate the origin of jetsam ambergris, we analysed DNA from an ambergris sample collected from a sperm whale beached in The Netherlands and compared it with DNA sequences isolated from jetsam ambergris collected from beaches in New Zealand and Sri Lanka.…”