Abstract
The degree of conflict between otter conservation and fish farming was assessed at Sado estuary (SW Portugal), using ecological (otter visiting rates to fish farms and consumption of commercial fish) and socio-economic (past and current instruments and policies addressing the conflict and a social impact assessment, including a discourse analysis of relevant stakeholders) parameters. The study concerned 14 fish farms producing Sparus aurata, Dicentrarchus labrax, Solea senegalensis and Solea solea. Results indicate high visiting rates in most fish farms (average: 76%), although in only 29%, species stocked were the most consumed prey. Other marine species and freshwater prey were the basis of otter diet in the remaining fish farms. The conflict is quite consensual among most fish farmers, and the results indicate that the perceived conflict by fish farmers has an ecological basis, although there are large gaps between effective and perceived predation. No specific instruments exist in Portugal to address the conflict, but some not specifically targeted can have an effect (e.g. species protection legislation and aquaculture licensing), although with limitations to effectively contribute to its mitigation (e.g. lack of enforcement and supervision). Formulating and assessing solutions is the following step, using a participatory approach to the development and evaluation of mitigation/compensation strategies, capable of providing an effective reconciliation of the conflict.
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Notes
QSR Software, La Trobe University, Australia (http://www.qsr.com.au/software/n4/n4.htm).
Six percent of both total and marine fish farms in Portugal are set up in the “Lisboa e Vale do Tejo” (LVT) region. But considering only marine fish farms (i.e., excluding bottom culture and cages), the proportion of units in the LVT region rises up to 56%, meaning that the region concentrates the largest number of these type of sites in the country (58).
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Acknowledgements
This study was conducted with the financial support of the European Union (contract number EVK2-CT-2002-00142-FRAP) and the Fundação para a Ciência e Tecnologia (FCT, SFRH/BD/5163/2001). The authors wish to thank to the colleagues who helped in the fieldwork: Ana Rita Alves, Joana Caixinha and Gonçalo Trindade.
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Freitas, D., Gomes, J., Luis, T.S. et al. Otters and fish farms in the Sado estuary: ecological and socio-economic basis of a conflict. Hydrobiologia 587, 51–62 (2007). https://doi.org/10.1007/s10750-007-0693-7
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DOI: https://doi.org/10.1007/s10750-007-0693-7