Aggregation of European storm-petrel (Hydrobates pelagicus ssp. melitensis) around cage fish farms. Do they benefit from the farmś resources?
Cage aquaculture aggregates wild fauna due to food provision. Several seabirds frequent fish farms, including the European storm-petrel (Hydrobates pelagicus melitensis). This work investigates the presence of storm-petrels around two aquaculture areas interspersed between breeding colonies in western Mediterranean Sea. Contribution of aquaculture-derived resources to their diet was assessed. Storm-petrels were mist-netted at the colonies and marked by bleaching feathers. Density around aquaculture areas was estimated through visual counts. Marks recognition was conducted visually and by photo-capture. Storm-petrel regurgitates were used as target tissue to estimate diet sources contribution. Contribution of surface zooplankton, ichthyoplankton and aquaculture wastes was estimated through Bayesian mixing modelling combining carbon and nitrogen stable isotopes and fatty acids as biomarkers. Storm-petrel density was high in open-sea aquaculture area, but not observed around near shore farms. Temporal variability of storm-petrels density during the breeding season was linked to their reproductive phenology. Within the open-sea aquaculture area, bluefin tuna farm was more attractive for storm-petrels than seabream/seabass farms. Visual identification of bleaching marks was not useful. Photo-capture showed that 8.3% of the storm-petrels watched around farms were firstly trapped in some of the nearby colonies, and 91.7% were unmarked. Qualitative evidence of aquaculture-derived wastes utilization was obtained. However, its estimated contribution was low (4.3%) when compared to ichthyoplankton (61.1%) or zooplankton (34.6%). The studied open-sea farms significantly aggregated storm-petrels along their entire breeding season. Storm-petrels got a slight profit from aquaculture resources. Nevertheless, some concerns arise regarding the cost/benefit balance of the interaction.
Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), Estación de Acuicultura Marina, Puerto de San Pedro del Pinatar, 30740, Murcia, Spain. Electronic address: felipe.aguado@carm.es.
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Aguado-Giménez
Asociación de Naturalistas del Sureste (ANSE), Plaza Pintor José María Párraga, 11, 30002, Murcia, Spain.
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Sallent-Sánchez
MENDIJOB S.L., C/. Rambla 22, El Palmar, 30120, Murcia, Spain.
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Eguía-Martínez
Asociación de Naturalistas del Sureste (ANSE), Plaza Pintor José María Párraga, 11, 30002, Murcia, Spain.
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Martínez-Ródenas
Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), Estación de Acuicultura Marina, Puerto de San Pedro del Pinatar, 30740, Murcia, Spain.
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Hernández-Llorente
Grupo Anillamiento Rodopechys., C/ Libia 3, 7J, 04009, Almería, Spain.
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Palanca-Maresca
Grupo Anillamiento Rodopechys., C/ Libia 3, 7J, 04009, Almería, Spain.
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Molina-Pardo
MENDIJOB S.L., C/. Rambla 22, El Palmar, 30120, Murcia, Spain.
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López-Pastor
Asociación de Naturalistas del Sureste (ANSE), Plaza Pintor José María Párraga, 11, 30002, Murcia, Spain.
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García-Castellanos
Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), Estación de Acuicultura Marina, Puerto de San Pedro del Pinatar, 30740, Murcia, Spain.
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Ballester-Moltó
Asociación de Naturalistas del Sureste (ANSE), Plaza Pintor José María Párraga, 11, 30002, Murcia, Spain.
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Ballesteros-Pelegrín
Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), Estación de Acuicultura Marina, Puerto de San Pedro del Pinatar, 30740, Murcia, Spain.
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García-García
Asociación de Naturalistas del Sureste (ANSE), Plaza Pintor José María Párraga, 11, 30002, Murcia, Spain; Department of Soil and Water Conservation, CSIC-CEBAS, PO Box 164, Campus Universitario, 30100, Murcia, Spain.
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Barberá
D000818:Animals; D017756:Aquaculture / Q000379:methods / Q000706:statistics & numerical data*; D001499:Bayes Theorem; D001717:Birds / Q000502:physiology*; D003362:Cost-Benefit Analysis; D008522:Mediterranean Sea
Aggregation; Bayesian mixing model; Cage aquaculture; Diet contribution; European storm-petrel; Fatty acids; Hydrobates pelagicus melitensis; Stable isotopes