Environmental Microbiota Related to Bacterial Carriage in Cultivated Trout (Onchorhyncus mykiss and Salvenilus fontinalis)

The recent introduction and spreading of new pathogens, along with the global climate change, has contributed to a considerable decrease in trout production. The increase of fish production presumes the avoidance and control of limiting noxious factors (Purser and Forteath, 2003; Sedgwick, 1990; Shepherd and Bromage, 1992). The presence of potentially pathogenic bacteria in fish of different age categories (n=10/ basin) and level of bacterial contamination of culture waters (12 basins) on a commercial trout farm with mixed population of rainbow and brook trout was monitored by insemination on McConkey agar and use of ID 32 E, API 20NE and API Staph galleries. Both fish and culture waters were higly polluted with bacteria, but the highest bacterial load was found in commercial trout, suggesting the vulnerability of this age category. The pottentially pathogenic bacteria for both fish (Aeromonas hydrophila) and humans (E. coli) indicated technological failure and potential fecal polution of the waters, increasing the risk for handlers and consumers.