Photo-Identification Methods Reveal Seasonal and Long-Term Site-Fidelity of Risso’s Dolphins (Grampus griseus) in Shallow Waters (Cardigan Bay, Wales)
Marijke N. de Boer, Josephine Clark, Mardik F. Leopold, Mark P. Simmonds, Peter J. H. Reijnders
Wageningen IMARES, Institute for Marine Resources and Ecosystem Studies, Den Burg, The Netherlands.
Wageningen IMARES, Institute for Marine Resources and Ecosystem Studies, Den Burg, The Netherlands; Wageningen University, Dept. Aquatic Ecology and Waterquality Management, Wageningen, The Netherlands.
Wageningen IMARES, Institute for Marine Resources and Ecosystem Studies, Den Burg, The Netherlands; Wageningen University, Dept. Aquatic Ecology and Waterquality Management, Wageningen, The Netherlands; WDC, Whale and Dolphin Conservation, Chippenham, UK.
WDC, Whale and Dolphin Conservation, Chippenham, UK.
DOI: 10.4236/ojms.2013.32A007   PDF   HTML     7,979 Downloads   11,861 Views   Citations


A photo-identification study on Risso’s dolphins was carried out off BardseyIslandinWales(July to September, 1997-2007). Their local abundance was estimated using two different analytical techniques: (1) mark-recapture of well-marked dolphins using a ‘closed-population’ model; and (2) a census technique based on the total number of identified individual dolphins sighted over the study period. The mark-recapture estimates of 121 (left sides; 64 - 178 95% CI; CV 0.24) and 145 dolphins (right sides; 78 - 213 95% CI; CV 0.24) closely matched the census technique estimates (population size of 90 - 151). It was found that the dolphins showed a degree of long-term and seasonal site-fidelity. A first long-distance match was made for Risso’s dolphins (319 km) betweenBardseyIslandandCornwall, confirming they can be wide-ranging animals. This study demonstrates that the combination of systematic and opportunistic photo-ID studies has complementary value as a population assessment tool in generating the first local abundance estimate for Risso’s dolphins inUKwaters. From the conservation perspective, these studies confirm the regular presence of Risso’s dolphins in these waters and the presence of calves shows breeding.BardseyIslandmay be part of a network of localities that are important habitats to this species where it may take advantage of prey abundance in shallow waters. As such, results of this study may provide assistance to include the Risso’s dolphin in future regional conservation strategies including the envisaged marine protected areas.

Share and Cite:

M. Boer, J. Clark, M. Leopold, M. Simmonds and P. Reijnders, "Photo-Identification Methods Reveal Seasonal and Long-Term Site-Fidelity of Risso’s Dolphins (Grampus griseus) in Shallow Waters (Cardigan Bay, Wales)," Open Journal of Marine Science, Vol. 3 No. 2A, 2013, pp. 66-75. doi: 10.4236/ojms.2013.32A007.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] J. Wharam and M. P. Simmonds, “Risso’s Dolphin Conservation Plan for Waters West of the UK,” 2008.
[2] P. Evans, P. Anderwald and M. Baines, “UK Cetacean Status Review,” 2003.
[3] J. Reid, P. Evans and S. Northridge, “Atlas of Cetacean Distribution in NW European Waters,” 2003.
[4] G. Bearzi, R. R. Reeves, E. Remonato, N. Pierantonio and S. Airoldi, “Risso’s Dolphin Grampus griseus in the Mediterranean Sea,” Mammal Biology, Vol. 76, No. 4, 2010, pp. 385-400. doi:10.1016/j.mambio.2010.06.003
[5] A. Gannier and O. Gannier, “Abundance of Grampus griseus in Northwestern Mediterranean,” European Research Cetaceans, Vol. 8, 1994, pp. 99-102.
[6] A. Gómez de Segura, E. Crespo, S. Pedraza, P. Hammond and J. Raga, “Abundance of Small Cetaceans in Waters of the Central Spanish Mediterranean,” Marine Biology, Vol. 150, 2006, pp. 149-160. doi:10.1007/s00227-006-0334-0
[7] SCANS-II, “Final Report Submitted to the European Commission,” 2008.
[8] C. R. Weir, C. Pollock, C. Cronin and S. Taylor, “Cetaceans of the Atlantic Frontier, North and West of Scotland,” Continental Shelf Research, Vol. 21, 2001, pp. 1047-1071. doi:10.1016/S0278-4343(00)00124-2
[9] P. S. Hammond, “Estimating the abundance of marine mammals,” In: L. Boyd, W. D. Bowen and S. J. Iverson, Eds., Marine Mammal Ecology and Conservation. Oxford University Press, New York, 2010, pp. 42-67.
[10] K. L. Hartman, F. Visser and A. Hendriks, “Social Structure of Risso’s Dolphins at the Azores: A Stratified Community Based on Highly Associated Social Units,” Canadian Journal of Zoology, Vol. 86, No. 4, 2008, pp. 294-306. doi:10.1139/Z07-138
[11] S. Airoldi, F. Bedninoni, A. Azzellino., V. Fadda and A. Profice, “Abundance Estimate of Risso’s Dolphins in the WESTERN Ligurian Sea through Mark-Recapture,” Proceedings of the 19th Annual Conference of the European Cetacean Society, La Rochelle, 2005, p. 109.
[12] M. N. de Boer, M. Morgan-Jenks, M. Taylor and M. P. Simmonds, “The small cetaceans of Cardigan Bay, UK,” British Wildlife, Vol. 4, 2002, pp. 246-254.
[13] M. N. de Boer, “Bardsey Island Cetacean Survey,” Conference Proceedings of Marine and Freshwater Monitoring, Cardiff, 19-20 November 2005, p. 1.
[14] T. Atkinson, A. Gill and P. G. H. Evans, “A Photo-Identification Study of Risso’s Dolphins in the Coastal Waters of the Eye Peninsula, Isle of Lewis, Scotland,” European Research Cetaceans, Vol. 11, 1997, p. 170 .
[15] M. N. de Boer, S. Eisfeld and M. P. Simmonds, “The Fine-Scale Habitat Use of Risso’s Dolphins off Bardsey Island, Cardigan Bay (UK),” Proceedings of the first European Cetacean Society workshop on Risso’s dolphin, Galway, 25 March 2012, p. 6.
[16] E. Rexstad and K. Burnham, “User’s Guide for Interactive Program CAPTURE,” Colorado State University, Fort Collins, 1991.
[17] B. Wilson, P. S. Hammond and P. S. Thompson, “Estimating Size and Assessing Trends in a Coastal Bottlenose Dolphin Population,” Ecology Applications, Vol. 9, No. 1, 1999, pp. 288-300. doi:10.1890/1051-0761(1999)009[0288:ESAATI]2.0.CO;2
[18] D. L. Otis, K. P. Burnham, G. C. White and D. R. Anderson, “Statistical Inference from Capture Data on Closed Animal Populations,” Wildlife Monographs, Vol. 62, 1978, pp. 1-35.
[19] K. H. Pollock, J. D. Nichols, C. Brownie and J. E. Hines, “Statistical Inference for Capture-Recapture Experiments,” Wildlife Monographs, Vol. 107, 1990, pp. 1-97.
[20] J. A. Williams, S. M. Dawson and E. Slooten, “The Abundance and Distribution of Bottlenosed Dolphins in Doubtful Sound, New Zealand,” Canadian Journal of Zoology, Vol. 71, No. 10, 1993, pp. 2080-2088. doi:10.1139/z93-293
[21] K. P. Burnham and W. S. Overton, “Estimation of the Size of a Closed Population When Capture Probabilities Vary among Animals,” Biometrika, Vol. 65, No. 3, 1978, pp. 625-633. doi:10.1093/biomet/65.3.625
[22] B. K. Williams, J. D. Nichols and M. J. Conroy, “Estimating Abundance for Closed Populations with MarkRecapture Methods-Analysis and Management of Animal Populations,” Academic Press, London, 2002.
[23] P. G. H. Evans and P. S. Hammond, “Monitoring Cetaceans in European Waters,” Mammal Review, Vol. 34, No. 1, 2004, pp. 131-156. doi:10.1046/j.0305-1838.2003.00027.x
[24] N. David and L. Di Méglio, “First Results of Summer Movements of Grampus griseus (Cuvier, 1812) in the N Mediterranean Sea,” European Research Cetaceans, Vol. 13, 1999, pp. 189-194.
[25] S. Airoldi, A. Azzellino, V. Fadda, S. Gaspari, B. Nani, M. Zanardelli, G. Notarbartolo di Sciara and M. Mariani, “Social Ecology of Risso’s Dolphins in the Ligurian Sea: Preliminary Results,” European Research Cetaceans, Vol. 14, 2000, pp. 213-217.
[26] A. M. Canadas and R. Sagarminaga, “Preliminary Results of Photo-Identification Studies on Risso’s Dolphins Undertaken during Surveys of Cetacean Distribution and Dynamics along the SE Coast of Spain: 1992-1995,” European Research Cetaceans, Vol. 10, 1997, pp. 222-224.
[27] R. S. Wells, C. A. Manire, L. Byrd, D. R. Smith, J. G. Gannon, D. Fauquier and K. Mullin, “Movements and dive patterns of a rehabilitated Risso’s dolphin, Grampus griseus, in the Gulf of Mexico and Atlantic Ocean,” Marine Mammal Science, Vol. 25, No. 2, 2009, pp. 420-429. doi:10.1111/j.1748-7692.2008.00251.x
[28] E. Hoyt, “Marine Protected Areas for Whales, Dolphins and Porpoises: A World Handbook for Cetacean Habitat Conservation,” Earthscan, London, 2010.

Copyright © 2023 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.