Beck S.,Mayo Institute of Technology, Galway |
Foote A.D.,Copenhagen University |
Kotter S.,Hebridean Whale and Dolphin Trust |
Harries O.,Hebridean Whale and Dolphin Trust |
And 4 more authors.
Journal of the Marine Biological Association of the United Kingdom | Year: 2014
An assemblage of killer whales that has been sighted in waters off the west coast of the British Isles and Ireland has previously been shown to be isolated from other North Atlantic killer whale communities based on association patterns. By applying a Bayesian formulation of the Jolly-Seber mark-recapture model to the photo-identification data compiled from opportunistic photographic encounters with this population of killer whales, we show that such sparse and opportunistically-collected data can still be valuable in estimating population dynamics of small, wide-ranging groups. Good quality photo-identification data was collected from 32 encounters over 19 years. Despite a cumulative total of 77 identifications from these encounters, just ten individuals were identified and the remaining 67 identifications were re-sights of these ten animals. There was no detected recruitment through births during the study and, as a result, the population appears to be in a slight decline. The demography of the population was highly skewed towards older individuals and had an unusually high ratio of adult males, and we suggest that demographic stochasticity due to a small population size may be further impacting the population growth rate. We recommend that this population be managed as a separate conservation unit from neighbouring killer whale populations. © 2013 Marine Biological Association of the United Kingdom .
Robinson K.P.,Cetacean Research and Rescue Unit |
O'Brien J.M.,Mayo Institute of Technology, Galway |
Berrowi S.D.,Shannon Dolphin and Wildlife Foundation |
Berrowi S.D.,Irish Whale and Dolphin Group |
And 12 more authors.
Journal of Cetacean Research and Management | Year: 2012
The potential for long distance movements in common bottlenose dolphins (Tursiops truncatus) from six UK and Irish study sites was examined using photographs of natural markings. Here we provide the first evidence for long-term re-sightings between the Moray Firth, Inner Hebrides and across international borders to the Republic of Ireland as determined for eight individuals over a ten year period from 2001 to 2010. Minimum dispersal distances of up to 1,277km were resolved providing a new distance record for the species in European waters. Although none of the sightings were made within protected areas, several were made in waters used by animals from a Special Area of Conservation (SAC) revealing some evidence for connectivity between areas previously regarded as discrete. Our findings highlight the need to mitigate broader-scale anthropogenic impacts affecting these dolphins across multiple sites throughout their coastal range. Accordingly, we underline the importance of developing wider conservation measures for this species in UK and Irish waters, but particularly in prospective corridor areas potentially linking designated SACs in the Moray Firth, Cardigan Bay and Shannon Estuary.
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.
Cheney B.,University of Aberdeen |
Thompson P.M.,University of Aberdeen |
Ingram S.N.,University of Aberdeen |
Hammond P.S.,University of St. Andrews |
And 20 more authors.
Mammal Review | Year: 2013
The distribution, movements and abundance of highly mobile marine species such as bottlenose dolphins Tursiops truncatus are best studied at large spatial scales, but previous research effort has generally been focused on relatively small areas, occupied by populations with high site fidelity. We aimed to characterize the distribution, movements and abundance of bottlenose dolphins around the coasts of Scotland, exploring how data from multiple sources could be integrated to build a broader-scale picture of their ecology. We reviewed existing historical data, integrated data from ongoing studies and developed new collaborative studies to describe distribution patterns. We adopted a Bayesian multi-site mark-recapture model to estimate abundance of bottlenose dolphins throughout Scottish coastal waters and quantified movements of individuals between study areas. The majority of sightings of bottlenose dolphins around the Scottish coastline are concentrated on the east and west coasts, but records are rare before the 1990s. Dedicated photo-identification studies in 2006 and 2007 were used to estimate the size of two resident populations: one on the east coast from the Moray Firth to Fife, population estimate 195 [95% highest posterior density intervals (HPDI): 162-253] and the second in the Hebrides, population estimate 45 (95% HPDI: 33-66). Interaction parameters demonstrated that the dolphins off the east coast of Scotland are highly mobile, whereas those off the west coast form two discrete communities. We provide the first comprehensive assessment of the abundance of bottlenose dolphins in the inshore waters of Scotland. The combination of dedicated photo-identification studies and opportunistic sightings suggest that a relatively small number of bottlenose dolphins (200-300 individuals) occur regularly in Scottish coastal waters. On both east and west coasts, re-sightings of identifiable individuals indicate that the animals have been using these coastal areas since studies began. © 2012 Mammal Society/Blackwell Publishing.
Embling C.B.,University of St. Andrews |
Gillibrand P.A.,Scottish Association for Marine Science |
Gordon J.,University of St. Andrews |
Shrimpton J.,Hebridean Whale and Dolphin Trust |
And 2 more authors.
Biological Conservation | Year: 2010
The harbour porpoise is a highly mobile species and thus represents a considerable challenge in the context of using marine protected areas (MPAs) for conservation. The shelf waters off the west coast of Scotland have been identified as an area of year-round presence, high density in comparison to surrounding areas, and a high young to adult ratio in summer and are thus a suitable area for exploring the location of possible special areas of conservations (SACs) under the EU Habitats Directive. We carried out dedicated surveys over three summers in the southern Inner Hebrides and used generalised additive models (GAMs) to predict areas of high relative density for harbour porpoises for each year. After compensating for survey effects, static bathymetric and persistent hydrographic variables were used in a step-wise model selection procedure. In all years harbour porpoise distribution was best explained by maximum tidal current, with higher densities predicted in areas of low current, and the same high density areas predicted year-on-year. Perimeter-to-area ratio was used to identify which areas should be considered as a basis for designating SACs for harbour porpoise in this area, to form part of the Natura 2000 network. The method used here combines spatial modelling and perimeter-to-area ratio for selecting protected areas, a methodology which is suitable for the protection of other animal species. © 2009 Elsevier Ltd. All rights reserved.
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.
Booth C.G.,University of St. Andrews |
Embling C.,University of Exeter |
Gordon J.,Marine Ecological Research Ltd. |
Calderan S.V.,Hebridean Whale and Dolphin Trust |
Hammond P.S.,University of St. Andrews
Marine Ecology Progress Series | Year: 2013
The west coast of Scotland is comprised of complex coastlines and topography, and a range of physical processes influence its coastal marine environment. The region is host to one of the highest densities of harbour porpoise Phocoena phocoena in Europe. The aim of this study was to identify habitat preferences driving the distribution of harbour porpoise, to gain a better understanding of the spatial distribution of the species in the region, as well as to assess the consistency of such patterns across time and space. Visual and acoustic line-transect surveys were conducted between 2003 and 2010. Generalised Additive Models (GAMs) with Generalised Estimating Equations (GEEs) were used to robustly determine relationships between the relative density of harbour porpoises and temporally and spatially variable oceanographic covariates. Predictive models showed that depth, slope, spring tidal range and distance to land were consistently important in explaining porpoise distribution. Consistent preferences for water depths between 50 and 150 m and highly sloped regions were observed across the temporal models. Predicted distributions revealed a consistent inshore presence for the species throughout the west coast of Scotland and confirmed that predictable oceanographic features could help inform the establishment of Special Areas of Conservation (SACs) for the species. © Inter-Research 2013.
News Article | April 3, 2016
Experts say that killer whale, also known as Dopey Dick, is living off the west coast of Scotland. The orca became famous in November 1977 when it was first seen by locals in pursuit of a salmon prior to remaining five kilometers (3 miles) upriver of Loch Foyle for two days. Marine experts are tracking orcas, as they are the UK's only known resident population of killer whales in the west coast community of whales. Since 1994, the Hebridean Whale and Dolphin Trust has been continually monitoring the behavior of the west coast population of killer whales. Part of their documentation includes four males and four females that have never reproduced since their studies began. The orcas are not noted to interact with other orcas belonging in the north-east Atlantic community. Early this year, Lulu, one of the females was stranded near Tiree where it subsequently expired. The agency expressed that the discovering Dopey Dick as part of the west coast population is an important piece of information to understand the relative age of that particular orca population. Irish Whale and Dolphin Group sightings officer Padraig Whooley said that Dopey Dick's sighting puts the west coast community at the upper limits of the expected life expectancy of male orcas. "Adult males generally live to around 30 years, but with an upper range of 50 to 60 years," Whooley said. Based on Dopey Dick's initial sighting in 1977, he is believed to be an adult male back then. This present sighting places Dopey Dick to at least 50 years or older. A killer whale expert, Andy Foote shared that a photograph posted on Facebook showed Dopey Dick's white eye patch that sloped backwards is hard to miss. "I couldn't believe it - he was already a full-grown male back in 1977, when I was just five years old," Foote added. Dr. Conor Ryan of Hebridean Whale and Dolphin Trust said that Dopey Dick's sighting puts pressure on whale biologists to conduct more studies about this particular species before time runs out. He expresses concern that species like Comet may become extinct. "Since records began in the '80s, we haven't had any new animals join the population and we haven't had new calves either," said Ryan. "The population is declining because as the older animals die, they're not being replaced." Earlier this month, marine experts lauded the decision of Seaworld to finally stop breeding of orcas in captivity. The company also said that they are no longer training the orcas but instead showcase them in their natural setting. The decision came months after a trainer was attacked by a killer whale.