Shannon Dolphin and Wildlife Foundation

Kilrush, Ireland

Shannon Dolphin and Wildlife Foundation

Kilrush, Ireland
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Acampora H.,Mayo Institute of Technology, Galway | Berrow S.,Mayo Institute of Technology, Galway | Berrow S.,Shannon Dolphin and Wildlife Foundation | Newton S.,BirdWatch Ireland | O'Connor I.,Mayo Institute of Technology, Galway
Marine Pollution Bulletin | Year: 2017

Plastic pollution has been the subject of much research in the last decade. Seabirds can mistake plastic fragments for prey, which can perforate or block the digestive tract and cause ulcers. Most commonly, seabirds accumulate this indigestible matter in their stomachs, obtaining no nutrition and may die from starvation. Certain species of seabirds however, have the ability of regurgitating indigestible matter in the form of pellets. This study aimed to investigate the ingestion of plastics by live seabirds through the examination of regurgitated pellets (n = 92) from a Great Cormorant (Phalacrocorax carbo) breeding colony and a winter roost in Ireland. Plastic prevalence was consistently 3.2% at both sites. The presence of plastic litter highlights the fact that all species of seabird are susceptible to interact with marine litter regardless of feeding habits, although at different rates. More research is needed to understand the driving factors involved in plastic ingestion among different species. © 2017 Elsevier Ltd.

Foley A.,Mayo Institute of Technology, Galway | McGrath D.,Mayo Institute of Technology, Galway | Berrow S.,Shannon Dolphin and Wildlife Foundation | Gerritsen H.,Marine Institute of Ireland
Aquatic Mammals | Year: 2010

The Shannon Estuary is home to Ireland's only known resident population of bottlenose dolphins (Tursiops truncatus) and is designated as a candidate Special Area of Conservation (cSAC) for this species. Proper conservation management of these dolphins requires an understanding of the social structure of this population. Four years of photoidentification data (2005 to 2009, excluding 2007) were used to construct sociograms that complement a cluster analysis of individually marked dolphins and their associates. The results found little evidence of social stability or group fidelity for this study's dolphin population. Analysis of dolphins observed in consecutive years showed that the probability of group members encountering an individual dolphin in the second year did not depart from a random model. The social parameters for this resident population seem to be typical for this species. Bottlenose dolphins are found to exhibit a highly fluid, dynamic social structure within which individuals change their composition and associates regularly. These dolphins in the Shannon Estuary appear to live in a fission-fusion based society.

Barker J.,Shannon Dolphin and Wildlife Foundation | Berrow S.,Shannon Dolphin and Wildlife Foundation | Berrow S.,Mayo Institute of Technology, Galway
Biology and Environment | Year: 2016

Bottlenose dolphin group size is known to be determined by food availability, social interactions and predator defence. This paper analyses data gathered over seven years from dolphin tour boats operating in the Shannon Estuary and examines whether there were any temporal or spatial trends in group size of the resident group of bottlenose dolphins in the region. Findings indicate that dolphin group size varied significantly between years (ANOVA, F = 4.55, P = 0.0001), and increased during the months of July, September and October (ANOVA, F = 8.921, P < 0.0001). Findings also reveal that group size of dolphins encountered in the middle part of the estuary was greater than the outer or inner estuary (ANOVA, F = 4.176, P < 0.001). The seasonal change in group size is thought to be primarily caused by dolphins switching to different prey species. © Royal Irish Academy.

Berrow S.,Shannon Dolphin and Wildlife Foundation | Berrow S.,Mayo Institute of Technology, Galway | O'Brien J.,Mayo Institute of Technology, Galway | Groth L.,Mayo Institute of Technology, Galway | And 2 more authors.
Aquatic Mammals | Year: 2012

An abundance assessment of bottlenose dolphins (Tursiops truncatus) in the Lower River Shannon candidate Special Area of Conservation (cSAC) was undertaken between July and October 2010 using photo-identification. European Union Member States are obliged to designate SACs for bottlenose dolphins to protect important habitats. The Lower River Shannon is the only cSAC in Ireland for this species. A cumulative total of 273 bottlenose dolphins were photographed during the 12 transects, and from these a total of 116 individual animals were identified. They were categorized as follows: 71 with Severity Grade 1 marks, 21 with Severity Grade 2 marks, and 24 with Severity Grade 3 marks. There were 50 dolphins with permanent marks (Severity Grade 1) recorded on both sides of the dorsal fin, 64 on the left hand side only, and 57 on the right hand side only. There was an overlap, with some dolphins occurring in more than one category. Estimates of abundance were calculated using left side, right side, and both side identifications. The proportion of dolphins with re-identifiable marks (Severity Grade 1 only) ranged from 0.60 to 0.63. The estimated abundance of marked individuals was elevated depending on the estimated proportion of marked individuals in the population to give a final estimate of 107 ± 12, CV = 0.12 (95% CI = 83 to 131). Previous abundance estimates for bottlenose dolphins in the Lower River Shannon cSAC ranged from 114 in 2008 to 140 in 2006; the present estimate was within this range and also within the 95% Confidence Intervals for all surveys carried out to date. This suggests that, within the power of the survey technique, the population of bottlenose dolphins in the Lower River Shannon cSAC is relatively stable.

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.

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