Fish Health/Disease Mortality in Aquaculture Disease Contributing Factors Natural mortality: Broodstock – age related Disease Viruses, Fungi, Bacteria and Parasites Infection vs. Disease Most are stress-mediated Disease transmission Though water – Through egg/adults –

Fish Health/Disease Mortality in Aquaculture Preventative measures (Bio-security) Proper management Early diagnosis of disease – treat early Sanitation Vaccination Treatment Isolation and Environmental Manipulation

Fish Health/Disease Proper management Observation of fish Signs of stress Unusual behavior Skin lesions Secondary infections Due to stress Ex: Channel catfish in recirculation system Average wt: 1 kg Density: 600 g/l Healthy condition Power failure occurred Resulted in: - - Costia epizootic several days later Treatment with: Disease + treatment = stress = additional disease due to other pathogens 1 week later = all fish died due to secondary infections.

Fish Health/Disease Proper management Vaccines Sanitation Disinfection of all equipment, tanks, people, etc. Restrictions on visitors Disinfect boots, waders, etc. Vaccines Injection Immersion/spray Oral (feed) Ongoing research and development Viral and bacterial diseases

Fish Health/Disease Treatment Isolation Physical environment Isolate affected animals or groups Avoid contamination with uninfected groups Physical environment Disease treatments Temperature or salinity changes Re-circulation systems Ponds Difficult to treat