Impact of abiotic factors and husbandry on saprolegniosis in salmonid farms

Oomycetes of the genus Saprolegnia are widespread in freshwater environment and among main pathogens causing economic losses salmonid aquaculture. Infections by mycotic agents fish farming generally considered to result from chronic stress poor condition associated with water quality problems, adverse environmental conditions, frequent/rough/incorrect handling, concurrent infections, physiological changes reproduction immunocompromised animals. To identify risk factors for infections trout Atlantic salmon farming, longitudinal studies were carried out different Italian, Spanish, Scottish farms. Prevalence saprolegniosis mortality monitored over time statistically analysed respect husbandry factors. Overall, statistical results production cycle (trout vs farming) country indicate that prevalence may be influenced peculiarities culture system environment. Nevertheless, a specific set parameters, including lower temperature, handling procedures increased all Particularly, farms represented an important contribution mortality, was temperature pH, density within tanks. Similarly, influencing Moreover, molecular analyses confirmed role S. parasitica as pathogenic oomycete countries. The identification introduction increase infection will allow correct design biosecurity pathogen control strategies.