Fish HealthDisease Mortality in Aquaculture Contributing Factors 1

Fish Health/Disease • Mortality in Aquaculture – Contributing Factors 1. Natural mortality: Broodstock – age related 2. 3. 4. 5. 6. • Disease 1. Viruses, Fungi, Bacteria and Parasites 2. Infection vs. Disease • • Most are stress-mediated • • Though water – Through egg/adults – 3. Disease transmission

Fish Health/Disease • Mortality in Aquaculture – Preventative measures (Bio-security) 1. Proper management – – – Early diagnosis of disease – treat early 2. Sanitation 3. Vaccination – Treatment 1. 2. 3. Isolation and Environmental Manipulation

Fish Health/Disease • Proper management – Observation of fish • Signs of stress 1. 2. Unusual behavior 3. 4. 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 – 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 • 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 –