First record of lernaea cyprinacea (copepoda) in a native fish species from a brazilian river

• Autores: Aline Angelina Acosta, Edmir Daniel Carvalho, Reinaldo José da Silva
• Localización: The Biologist, ISSN-e 1994-9073, ISSN 1816-0719, Vol. 10, Nº. Extra 2 (julio-diciembre), 2012
• Idioma: inglés
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• Resumen

  • Lernaea cyprinacea is a lernaeid copepod usually known as anchor worm. The major harms caused by this parasite on fish hosts appear to be on the gills, triggering hemorrhage and necrosis with consequent decrease of breathing capacity. Lernaeid can also cause deep injuries in the tegument, external muscle tissue, eyes surface and even inner organs. Lernaea cyprinacea was introduced in Brazil with Cyprinus carpio, and it has currently been found in native fish species. This research aims to report the occurrence of L. cyprinacea parasitizing the native species Steindachnerina insculpta in a tributary of a Brazilian reservoir. The fish sampling was composed of 60 specimens of S. insculpta, collected during summer (October and November-2011), with half sampled in a lotic stretch and the other half in a lentic stretch of Taquari River. The fish were collected using gill nets, with mesh size ranging from 3 to 7 centimeter, set in the afternoon and removed early next morning. All samples were frozen after collecting and examined in the laboratory. Their surfaces were analyzed and the lernaeids were carefully removed from the host tissues using tweezers and needle syringes; after removing they were preserved in Alcohol Formalin Acetic Acid solution (AFA). From 60 S. insculpta analyzed, three were parasitized by L. cyprinacea showing low rate of infestation, with one parasite per host. One infested host was collected in a lentic stretch of Taquari River, and the other two in a lotic stretch. Among the lernaeids found, there were two pregnant and one non-pregnant female. One host was found with the parasite on the surface, the other attached to the muscle tissue through the cloaca, and the last one was attached to the muscle through one of the pectoral fins. Leanea cyprinacea has been found infesting native fish species in Brazil and other countries around the world. Hence, the present study is the first record of L. cyprinacea parasitizing the native S. insculpta, and further, it is the first record of this parasite in Taquari River, São Paulo State, Brazil. There are areas in this tributary that have not been influenced by damming yet, thus characterizing a natural environment. The problem of the lernaeosis found in native fishes inhabiting natural environments should be highlighted as well as the introduction of species.