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Estimating the impact of interactions between bottlenose dolphins and artisanal fisheries around the Balearic Islands
Article first published online: 8 NOV 2007
2007 by the Society for Marine Mammalogy
Marine Mammal Science
Volume 24, Issue 1, pages 112–127, January 2008
How to Cite
Brotons, J. M., Grau, A. M. and Rendell, L. (2008), Estimating the impact of interactions between bottlenose dolphins and artisanal fisheries around the Balearic Islands. Marine Mammal Science, 24: 112–127. doi: 10.1111/j.1748-7692.2007.00164.x
- Issue published online: 8 NOV 2007
- Article first published online: 8 NOV 2007
- Received: 29 March 2007Accepted: 31 July 2007
- fisheries interactions;
- bottlenose dolphin;
- Tursiops truncatus
Interactions between marine mammals and fisheries are a growing problem, and effective management requires assessment of the factors driving the interaction and of the impacts on fisheries. We used data from interactions between artisanal fisheries and bottlenose dolphins around the Balearic Islands to assess these factors and impacts. Observers collected data during 1,040 fishing operations over 3 yr. Location and year were important factors affecting interaction probability, with some areas showing large increases over the study period. We estimated the combined cost of catch loss and net damage as 6.5% of the total catch value (95% CI −12.3%, −1.6%), and the annual loss to be 3.4% (95% CI −6.5%, −0.1%) of the total catch by weight. This weight equates to the dietary needs of ∼12 dolphins (95% CI 0.2, 22), suggesting the fishery is not a vital food source for the dolphin population. Two dolphins died through entanglement during the observed fishing operations. We observed 3% of the total fishing activity, by weight, in 2003; scaling up this mortality directly suggests that as many as sixty dolphins may be dying in nets each year. This interaction likely has serious conservation implications for the dolphin population.