Biodiversity and Conservation

, 17:2323 | Cite as

Spatio-temporal analysis of cetacean strandings and bycatch in a UK fisheries hotspot

  • Ruth H. Leeney
  • Rachel Amies
  • Annette C. Broderick
  • Matthew J. Witt
  • Jan Loveridge
  • Joana Doyle
  • Brendan J. Godley
Original Paper

Abstract

Marine vertebrate strandings data can provide insights into the long-term dynamics of cetacean populations, and the threats they face. We investigate whether the spatio-temporal patterns of cetacean strandings around Cornwall, SW Britain, have changed in the past century. Analysis of strandings from 1911 to 2006 (n = 2,257) show that, since the mid-1970s, the relative frequency of strandings of common dolphins (Delphinus delphis), harbour porpoises (Phocoena phocoena) and pilot whales (Globicephala melas) has increased significantly. Seasonal peaks in strandings frequencies are apparent, between December and March for harbour porpoises and common dolphins, and between November and January for pilot whales. There were significant positive trends in the number of common dolphin and harbour porpoise strandings, as a proportion of total strandings, over time. Strandings of common dolphins, porpoises and all other species occur more frequently on the south coast of Cornwall. A total of 415 cetaceans were subject to full veterinary necropsy to determine cause of death, between 1990 and 2006, and 253 (61%) of these individuals were determined to have died due to bycatch in fishing gear. Analyses of industrialised fishing pressure in UK waters show the seas around Cornwall to be one of the most heavily fished areas of the UK. We suggest a number of factors that could be responsible for the recent increases in cetacean strandings in southwest UK waters in recent years, including survey effort, as well as abundance and range shifts that are potentially linked with climate change. Although detectable levels of bycatch rate have not increased over time, fisheries interactions are in significant part responsible for mortality patterns and are worthy of more detailed investigation.

Keywords

Cetacean communities Climate change Conservation Dolphin Porpoise Whale 

Supplementary material

10531_2008_9377_MOESM1_ESM.ppt (42 kb)
Fig. 2 suppl.(e) Bottlenose dolphins, (f) striped dolphins, (g) Risso’s dolphins, (h) minke whales. (PPT 42 KB)
10531_2008_9377_MOESM2_ESM.ppt (38 kb)
Fig. 3 suppl.(e) Bottlenose dolphins, (f) striped dolphins, (g) Risso’s dolphins, (h) minke whales. (PPT 38 KB)

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Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  • Ruth H. Leeney
    • 1
    • 2
  • Rachel Amies
    • 1
    • 3
  • Annette C. Broderick
    • 1
  • Matthew J. Witt
    • 1
  • Jan Loveridge
    • 4
  • Joana Doyle
    • 4
  • Brendan J. Godley
    • 1
  1. 1.Centre for Ecology and ConservationUniversity of ExeterCornwallUK
  2. 2.Provincetown Center for Coastal StudiesProvincetownUSA
  3. 3.School of Marine and Tropical BiologyJames Cook UniversityTownsvilleAustralia
  4. 4.Cornwall Wildlife Trust Marine Strandings NetworkCornwallUK

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