Trophic role and predatory interactions between blue crab, Callinectes sapidus, and native species in open waters of the Ebro Delta
[EN] The Ebro Delta has become a major blue crab (Callinectes sapidus) fishery area in the NW Mediterranean, but there is limited information on factors controlling the abundance of populations in open waters, a crucial habitat for ovigerous females. Here, we use a stable isotope approach (delta 15N...
| Autores: | , , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2024 |
| País: | España |
| Institución: | Universitat Politècnica de València (UPV) |
| Repositorio: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Idioma: | inglés |
| OAI Identifier: | oai:riunet.upv.es:10251/214072 |
| Acceso en línea: | https://riunet.upv.es/handle/10251/214072 |
| Access Level: | acceso abierto |
| Palabra clave: | Stable isotope analyses Isotopic niche overlap MixSiar 15N fractionation Octopus vulgaris TECNOLOGIA DEL MEDIO AMBIENTE |
| Sumario: | [EN] The Ebro Delta has become a major blue crab (Callinectes sapidus) fishery area in the NW Mediterranean, but there is limited information on factors controlling the abundance of populations in open waters, a crucial habitat for ovigerous females. Here, we use a stable isotope approach (delta 15N and delta 13C), to assess blue crab trophic position, the potential consumption of food items using mixing models, and the isotopic niche overlap with local commercial species. For Octopus vulgaris, a potential blue crab key predator, a trophic enrichment experiment was also conducted to further assess predation control in wild populations. The blue crab showed 1.6 times higher trophic position than in other habitats of the Ebro Delta, and similar to that found in the harbor crab, Liocarcinus depurator, and several predatory fish. Additionally, the isotopic niche of blue crabs showed overlaps from 46.2 to 14.9% with native predators, and mixing models also suggest even dietary contributions throughout the food web. For O. vulgaris, field results showed a trophic position of 3.93, lower than that of blue crab, and lower delta 15N signatures were also obtained in a captivity experiment drawing negative fractionation (-1.1%o). We conclude that high dietary contribution of animal prey might provide a high protein diet that could be crucial for allowing the maintenance of a large local population, but the overall functional trophic similarity could also disfavor local native species. The similarity between experimental fractionation and field differences between predator and prey (-1.6%o) suggests that predation of blue crab is possible, but further research is needed to clarify the metabolic routes involved in octopus delta 15N fractionation. |
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