Blood-feeding polyopisthocotylean monogeneans are one of the most important group among the emerging parasites of cultured marine fish. The pathogenic effect of these parasites may be increased by adverse environmental conditions or poor zootechnical management, favouring infections and epizootics. The meagre Argyrosomus regius is a species with an increasing importance in Mediterranean aquaculture, because of its great potential for the diversification of productions. In May 2007, two groups of meagre were put together in one offshore floating cage sited in northeastern Sardinia (western Mediterranean Sea). In September 2007 the fish showed non-specific disease signs, such as lethargy, emaciation, gill anaemia and mortality. From September 2007 to January 2008, 65 specimens of meagre of both groups were sampled for parasitological and microbiological analyses. Only one single species of parasite, the microcotylid monogenean Sciaenacotyle panceri, was found on the gills. No other protozoan or metazoan parasites were found and no bacteria or viruses were isolated. The infection peaked suddenly in both groups in September and part of October 2007, with all hosts infected by several hundred of worms. In the following months prevalence remained high (60-70%) while the intensity of infection decreased noticeably to few units. After the outbreak, a total mortality rate of 5-10% was estimated for the older fish group, while no noteworthy mortality was recorded in the other fish. At histology, the parasites were observed grasping the gill lamellae with an evident traumatic effect on the tissue up to amputation of lamellae. In some cases the total “stripping” of the gill filament was observed. The presence of Sciaenacotyle panceri on Argyrosomus regius has been rarely reported. Previously it was reported only from a single specimen of this fish species in the Gulf of Tunis, while all the other reports were referred to the shi drum Umbrina cirrosa in the Mediterranean Sea and eastern Atlantic Ocean. This is the first account of Sciaenacotyle panceri on the gills of cultured meagre as causative agent of disease and mortality. The presence of this parasite points out the need for improving the control strategies of the diseases of cultured meagre, and investigating the possible transfer of microcotylids from wild to caged fish.
Sciaenacotyle panceri (Monogenea, Microcotylidae), un possibile fattore limitante per l’allevamento in gabbia dell’ombrina boccadoro (Argyrosomus regius) nel Mar Mediterraneo
GUSTINELLI, ANDREA;FIORAVANTI, MARIALETIZIA
2010
Abstract
Blood-feeding polyopisthocotylean monogeneans are one of the most important group among the emerging parasites of cultured marine fish. The pathogenic effect of these parasites may be increased by adverse environmental conditions or poor zootechnical management, favouring infections and epizootics. The meagre Argyrosomus regius is a species with an increasing importance in Mediterranean aquaculture, because of its great potential for the diversification of productions. In May 2007, two groups of meagre were put together in one offshore floating cage sited in northeastern Sardinia (western Mediterranean Sea). In September 2007 the fish showed non-specific disease signs, such as lethargy, emaciation, gill anaemia and mortality. From September 2007 to January 2008, 65 specimens of meagre of both groups were sampled for parasitological and microbiological analyses. Only one single species of parasite, the microcotylid monogenean Sciaenacotyle panceri, was found on the gills. No other protozoan or metazoan parasites were found and no bacteria or viruses were isolated. The infection peaked suddenly in both groups in September and part of October 2007, with all hosts infected by several hundred of worms. In the following months prevalence remained high (60-70%) while the intensity of infection decreased noticeably to few units. After the outbreak, a total mortality rate of 5-10% was estimated for the older fish group, while no noteworthy mortality was recorded in the other fish. At histology, the parasites were observed grasping the gill lamellae with an evident traumatic effect on the tissue up to amputation of lamellae. In some cases the total “stripping” of the gill filament was observed. The presence of Sciaenacotyle panceri on Argyrosomus regius has been rarely reported. Previously it was reported only from a single specimen of this fish species in the Gulf of Tunis, while all the other reports were referred to the shi drum Umbrina cirrosa in the Mediterranean Sea and eastern Atlantic Ocean. This is the first account of Sciaenacotyle panceri on the gills of cultured meagre as causative agent of disease and mortality. The presence of this parasite points out the need for improving the control strategies of the diseases of cultured meagre, and investigating the possible transfer of microcotylids from wild to caged fish.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
