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Makelainen P.,University of Helsinki | Esteban R.,Conservation Information and Research on Cetaceans | Foote A.D.,Copenhagen University | Kuningas S.,University of St. Andrews | And 6 more authors.
Journal of the Marine Biological Association of the United Kingdom | Year: 2014

Here we present a comparison of saddle and eye patch patterns of killer whales from Norwegian, Icelandic, British, Spanish and Greenlandic waters. We found only a small amount of variation in saddle patch shapes, which may reflect a recent phylogenetic divergence from the most recent common ancestor. Eye patch shapes were more variable than saddle patches in small details. Most individuals had eye patches with parallel orientation, with the exception of a small group of killer whales from the Hebrides, which, as previously reported, had sloping eye patches that sloped downward at the posterior end. This differentiation in pigmentation patterns of the Hebridean killer whales from neighbouring populations could reflect one or more of several evolutionary processes, including a deeper phylogenetic divergence, low gene flow with other local populations and drift. © Marine Biological Association of the United Kingdom 2014. Source

Foote A.D.,University of Aberdeen | Simila T.,Wild Idea | Vikingsson G.A.,Iceland Marine Research Institute | Stevick P.T.,Hebridean Whale and Dolphin Trust
Evolutionary Ecology | Year: 2010

Movement, site fidelity and connectivity have important consequences for the evolution of population structure and therefore the conservation and management of a species. In this study photographs of naturally marked killer whales collected from sites across the Northeast Atlantic are used to estimate fidelity to sampling locations and movement between locations, expressed as transition probabilities, pt, using maximum likelihood methods. High transition probabilities suggest there is high inter-annual site fidelity to all locations, and large-scale movement between the spawning and wintering grounds of both Norwegian and Iceland stocks of Atlantic herring. There was no evidence of movement between the Norwegian herring grounds and Icelandic herring grounds, or between the mackerel fishing grounds and the herring fishing grounds. Thus the movement of predictable and abundant prey resources can lead to intrinsic isolation in this species We also find movement between the Northern Isles, Scotland and East Iceland. An association network indicates that killer whales predating seals around the Northern Isles, Scotland are linked to the community of killer whales that follow the Icelandic summer-spawning herring. This adds support to existing evidence of a broad niche width in some populations. © 2009 Springer Science+Business Media B.V. Source

Kuningas S.,University of St. Andrews | Simila T.,Wild Idea | Hammond P.S.,University of St. Andrews
Journal of the Marine Biological Association of the United Kingdom | Year: 2014

A long-term photo-identification study of killer whales (Orcinus orca) in northern Norway was initiated in 1986, when their prey the Norwegian spring-spawning herring (Clupea harengus) started to winter in a complex fjord system. The aim of this work was to estimate population size and apparent survival rates in this killer whale population using photo-identification and mark-recapture techniques with data collected during October-December 1986-2003. Total population size was estimated to be highest in 2003: 731 individuals (SE = 139, 95% CI = 505-1059) using a model taking heterogeneity of capture probabilities into account. Apparent survival of adult males and adult females was estimated using the Cormack-Jolly-Seber model as 0.971 (SE = 0.008) and 0.977 (SE = 0.009), respectively. Calving intervals ranged from 3 to 14 years (mean = 5.06, SE = 0.722). These are the first estimates of northern Norwegian killer whale population parameters, allowing their dynamics to be investigated and comparisons to be made with killer whale populations globally. © 2013 Marine Biological Association of the United Kingdom . Source

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