RESUMO
Introduced species have a major impact on freshwater ecosystems, particularly on islands. Numerous fish species have been introduced in Corsica (Mediterranean island, southern France) as part of planned programs or clandestinely. The introduction of non-native freshwater fish species can have a range of impacts on the recipient ecosystem, including through the co-introduction of its pathogens. A sample of introduced perch Perca fluviatilis Linnaeus, 1758 from the artificial reservoir of Padula was examined following a report of parasites by an angler. The analyses revealed the occurrence of Eustrongylides sp. (Nematoda) and Clinostomum complanatum (Digenea), two zoonotic parasites in P. fluviatilis. Both parasites are reported for the first time in France. Eustrongylides sp. and C. complanatum may have been introduced with their fish intermediate hosts or through their final bird hosts. The occurrence of the two parasites raises concerns from both a veterinary and human health perspective as they can use a wide range of amphibians as intermediate hosts and can be acquired in humans through the consumption of raw or undercooked fish.
Assuntos
Doenças dos Peixes , Espécies Introduzidas , Percas , Animais , França , Doenças dos Peixes/parasitologia , Percas/parasitologia , Trematódeos/isolamento & purificação , Trematódeos/classificação , Zoonoses/parasitologia , Infecções por Trematódeos/veterinária , Infecções por Trematódeos/parasitologia , Ilhas , HumanosRESUMO
Phoxinus minnows are small freshwater fish found throughout Eurasia. The taxonomy of this genus is still under investigation, and new species are regularly described. They are frequently introduced outside their native range due to their use as live bait for angling, and such fish introductions can have diverse impacts on the recipient areas. Before the rise in interest regarding the diversity of this genus in the past 15 years, studies carried out on their biology and ecology reported their findings for the Eurasian minnow Phoxinus phoxinus Linnaeus, 1758, which was then considered ubiquitous. A parasites checklist for Phoxinus minnows has yet to be published, and the recent progress on the taxonomy of this genus has enabled us to propose a reassignment of parasite records to their proper host. The most thoroughly studied potential species were the North European species Phoxinus sp. 7 sensu Palandacic et al. 2017, Phoxinus isetensis, and P. phoxinus. We were able to highlight a gap in knowledge for numerous species that have received little-to-no attention in terms of parasitology. Systematic molecular identification of Phoxinus minnows should be conducted when studying their parasites, as a reliable identification of the host is vital in parasitology research. Future research will certainly reveal a species-specific composition of the parasitofauna occurring in Phoxinus, especially among widespread parasites such as Gyrodactylus and Diplostomum. Such specificities could even become tools for assessing the introduction routes of Phoxinus species.
RESUMO
To gain insight into the impact of bottom-up changes in the plankton community on planktivorous fish in the context of the decline of small pelagic fisheries in the Northwestern Mediterranean Sea, we have conducted an extensive year-long study. The investigation combined biochemical analyses (proteins, carbohydrates, and lipids) with C and N stable isotope analyses (SIA) to simultaneously study phytoplankton, zooplankton, and eight planktivorous fish species (Engraulis encrasicolus, Sardina pilchardus, Sardinella aurita, Sprattus sprattus, Cepola macrophthalma, Chromis chromis, Boops boops, and Spicara maena). This study is the first to analyze both stable isotope and biochemical compositions in coastal particulate organic matter (POM) size classes (0.7-2.7 µm, 2.7-20 µm, and 20-200 µm), zooplankton size classes (200-300 µm, 300-500 µm, 500-1000 µm, 1000-2000 µm, and >2000 µm), and taxonomic groups. We demonstrated that: (1) POM stable isotope compositions varied based on its spatial origin, the taxonomic composition of its biota, and its biochemical content; (2) δ15N values increased with zooplankton size classes and groups, indicating different trophic levels; (3) Phytoplankton exhibited a lipid-rich composition (â¼55%), while zooplankton and fish muscles were protein-rich (â¼61% and â¼66%, respectively). Bayesian stable isotope mixing models revealed that, on average: (1) POM from oceanic waters contributed the most to the POM in the bay (>51%), with a dominance of pico-POM (â¼43%); (2) The 200-1000 µm zooplankton primarily consumed nano-POM, the 1000-2000 µm zooplankton mostly consumed micro-POM (â¼64%), and the >2000 µm zooplankton also mostly consumed micro-POM; (3) Mesozooplankton (200-2000 µm) constituted the main portion (â¼42%) of the diet for planktivorous fish species, while macrozooplankton organisms (>2000 µm) were the primary food resource (â¼43%) for both B. boops and S. sprattus. Our study underscores the complexity of the pelagic food web and highlights the bottom-up transfer of organic matter from the smallest phytoplankton size fractions to planktivorous fish.