Monitoring winter and summer abundance of cetaceans in the Pelagos Sanctuary (northwestern Mediterranean Sea) through aerial surveys

Systematic long-term monitoring of abundance is essential to inform conservation measures and evaluate their effectiveness. To instigate such work in the Pelagos Sanctuary in the Mediterranean, two aerial surveys were conducted in winter and summer 2009. A total of 467 (131 in winter, 336 in summer)...

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Bibliographic Details
Published in:PloS one 2011-07, Vol.6 (7), p.e22878
Main Authors: Panigada, Simone, Lauriano, Giancarlo, Burt, Louise, Pierantonio, Nino, Donovan, Greg
Format: Article
Language:English
Subjects:
Abundance
Aerial surveys
Aircraft
Animals
Biology
Cetacea
Conservation
Conservation of Natural Resources
Data Collection
Delphinus
Delphinus delphis
Dolphins
Dolphins & porpoises
Dolphins (Mammals)
Earth Sciences
Environmental Monitoring
Environmental protection
Estimates
Fin Whale
Fisheries
International agreements
Marine mammals
Marine protected areas
Mediterranean Sea
Monitoring
Population Density
Protected areas
Seasons
Ships
Stenella
Studies
Summer
Surveys
Trends
Whales
Whales & whaling
Winter
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Summary:Systematic long-term monitoring of abundance is essential to inform conservation measures and evaluate their effectiveness. To instigate such work in the Pelagos Sanctuary in the Mediterranean, two aerial surveys were conducted in winter and summer 2009. A total of 467 (131 in winter, 336 in summer) sightings of 7 species was made. Sample sizes were sufficient to estimate abundance of fin whales in summer (148; 95% CI = 87-254) and striped dolphins in winter (19,462; 95% CI = 12 939-29 273) and in summer (38 488; 95% CI = 27 447-53 968). Numbers of animals within the Sanctuary are significantly higher in summer, when human activities and thus potential population level impacts are highest. Comparisons with data from past shipboard surveys suggest an appreciable decrease in fin whales within the Sanctuary area and an appreciable increase in striped dolphins. Aerial surveys proved to be more efficient than ship surveys, allowing more robust estimates, with smaller CIs and CVs. These results provide essential baseline data for this marine protected area and continued regular surveys will allow the effectiveness of the MPA in terms of cetacean conservation to be evaluated and inform future management measures. The collected data may also be crucial in assessing whether ship strikes, one of the main causes of death for fin whales in the Mediterranean, are affecting the Mediterranean population.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0022878