Relative abundance, density and distribution of the harbour porpoise ( Phocoena phocoena ) along the west coast of the UK
The harbour porpoise (Phocoena phocoena) is the most frequently sighted cetacean in the UK, yet there is a conservation need to assess both abundance and distribution for this species. During May–August, 2002–2004 a boat-based visual survey, employing effort-related line transect methodology was con...
| Published in: | Journal of the Marine Biological Association of the United Kingdom |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Cambridge University Press (CUP)
2008
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1017/s0025315408001173 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0025315408001173 |
| Summary: | The harbour porpoise (Phocoena phocoena) is the most frequently sighted cetacean in the UK, yet there is a conservation need to assess both abundance and distribution for this species. During May–August, 2002–2004 a boat-based visual survey, employing effort-related line transect methodology was conducted for specified areas of the west coast of the UK. Estimates of relative abundance were made, with full DISTANCE analysis being carried out during 2004 for each of the areas surveyed. A generalized additive model (GAM) was constructed examining porpoise presence in relation to month, position (latitude and longitude), depth and sea surface temperature for all years and for each year of the study individually. Harbour porpoise density showed a significant decrease in the South West, with an increase for West Scotland over the study period, whilst the highest numbers for both Northern Ireland and the Firth of Clyde were recorded in 2003. The porpoise population in the south-west of England was estimated at 163 (67 LCI –400 UCI ) individuals during the months of May and June, 387 (170 LCI –877 UCI ) individuals were present off Northern Ireland during July, 1645 (823 LCI –3289 UCI ) individuals around the Firth of Clyde in July and 3105 (2032 LCI –4745 UCI ) off West Scotland during August and September. The GAM demonstrated that porpoise presence increased around the 100 m depth contour. Whilst further research is required in each of the areas throughout the year, this study provides important information on the distribution and habitat use of the harbour porpoise within UK waters. |
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