This study describes the macroscopic and microscopic lesions in farmed rainbow trout (Oncorhynchus mykiss) naturally infected with genetically identified Aeromonas salmonicida, A. hydrophila, and A. veronii species. The genus Aeromonas includes bacteria that naturally inhabit both waterways and organisms. At least 27 Aeromonas species have been identified to date, some of which can cause significant economic losses in aquaculture. As up to 68.8% of Aeromonas isolates may be misidentified in routine biochemical and phenotypic tests, however, reported cases of Aeromonas infection in fish may be wrongly identified. Our findings confirmed that the 3 Aeromonas species studied are associated with septicemia and dermal lesions in rainbow trout.

Objective: To validate the use of radiography to determine the length of sagittal otoliths in intact bogue (Boops boops; a sparid fish [commonly called sea bream]). Sample: 52 bogue cadavers. Procedures: Weight and standard lengths (from the tip of the snout to the caudal end of the last vertebra) of fish were measured. The radiographic beam was centered over the postorbital area, and images were obtained via ventrodorsal, 30° right dorsal–left ventral oblique, and 30° left dorsal–right ventral oblique projections. Otoliths were removed from the fish; sagittae were measured directly and on radiographic images by use of a vernier caliper. The relationship between direct and radiographic measurements of sagittal otoliths was calculated. Results: Paired sagittal, lapillus, and asteriscus otoliths were identified. Sagittal otoliths were comma-shaped on ventrodorsal projections; in oblique projections, they appeared ovoid and pairs of otoliths were located in the same dorsal plane. Radiographic length of sagittal otoliths was significantly correlated with directly measured length, and radiographic measurements were not significantly different between ventrodorsal and oblique radiographic projections. Conclusions and Clinical Relevance: Radiographic examination of sagittae was useful to determine the length of sagittal otoliths and, consequently, the fish length. In ecological applications, the radiographic measurement of sagittal otolith length may be useful for studies on the aquatic diet of organisms (fish, pinnipeds, and marine birds) because it allows for quick back-calculation to the size of prey.