A collection of 94 Vibrio isolates closely related to Vibrio harveyi, together with named reference and type strains, were investigated for phenotypic and genotypic properties. Using amplified fragment length polymorphism (AFLP), nine clusters were recognized. The largest cluster (n = 36), considered to be the bona fide V. harveyi group, contained the type strains of V. harveyi and Vibrio carchariae and most of the strains isolated from fish. The type strains of all other species, including Vibrio alginolflicus, Vibrio parahaemo/flicus, Vibrio campbellii and Vibrio natriegens, clustered outside this group. By ribotyping, V. harveyi and V. carchariae patterns were very similar, insofar as they shared most bands. The V. campbellii type strain had several bands in common with the type strains of both V. harveyi and V. carchariae, whereas the other species were clearly distinct from these three species. DNA-DNA hybridization experiments showed 88% DNA binding between the type strains of V. harveyi and V. carchariae, whereas the DNA binding between V. harveyi and V. campbellii was 40%. Although the delineation of the species V. harveyi is still uncertain, the authors propose, on the basis of a number of tests, to delineate a core of V. harveyi strains which contained the type strains of both V. harveyi and V. carchariae. It is concluded that V. camhariae is the junior synonym of V. harveyi.

In the first part of a national survey of gyrodactylid parasites, with spécial référence to Gyrodactylus salaris, funded by French administrations, two water basins harbouring Atlantic salmon were sampled : Brittany (7 rivers and 3 restocking farms) and the Adour basin in the Western Pyrénées (6 rivers and 1 restocking farm). 535 salmonids were collected and examined for G. salaris and other gyrodactylid species investigations.Identification procédure was performed by morphological examination and molecular analysis. Both methods led to the same conclusions with a high degree of consistency :Gyrodactylus salaris was declared absent from the examined samples and, therefore, can be considered absent from the sampled water basins with a high level of confidence (over 99.4 %).A new Gyrodactylus species was identified first by morphological examination and confirmed by molecular analysis. This new species is named Gyrodactylus teuchis (CUNNINGHAM et al., in prep.). This resuit has been confirmed by an independent study performed in the same time (Dr. C.O. CUNNINGHAM, personal communication). G. teuchis shares several morphological and molecular characters with G. salaris. The wrong identification of the latter in France by JOHNSTON et al. (1996)

The relative degree and duration of protection against Vibrio uriguillarurii and Pasteurellu piscicidu in sea bass vaccinated once by immersion at 1 g was compared with fish vaccinated by immersion at 1 g and revaccinated at 5 g by immersion or intraperitoneal (i.p.) injection. The vaccines used were based on V. anguilluruni (serotype 01) and P. piscicidu. The groups of fish were challenged with both pathogens separately at 7 weeks and 26 weeks post revaccination. Sea bass vaccinated by immersion at I g and again at 5 g by immersion o r injection, demonstrated a significant level of protection against V. aiiguillaruni lasting for 26 weeks post revaccination. Sea bass revaccinated by immersion were significantly protected against P. piscicidu 7 weeks post revaccination compared with nonvaccinated fish. Failure in killing nonvaccinated sea bass during the latter pasteurellosis challenge renders duration of protection against P. piscicida beyond 7 weeks post revaccination as inconclusive. No long-term protection was measured against either pathogen in the fish vaccinated at 1 g.

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