To vannamei or not to vannamei …
… that is the question
Marine Cage Culture Sites
Movement of shrimps between countries within a species’ range is
okey.Borders between countries are political …
Shrimps don’t know that.
Marine Cage Culture Sites
Movement of fish outside its biological barrier is debatable! AllQuarantine new arrivals … it could
save the others!
A hypothetical “exotic shrimp transfer network”A hypothetical “exotic shrimp transfer network”
Motive for species introduction:
• When a native organism is not suitable for aquaculture
• When culture of the native stock crashes
Consequences of Movement
• when a species is introduced, it is not just individuals of that organism that travel … parasites and diseases that the organisms suffer from travel as well
• Problems arise when the exotic organisms escape from culture facilities either in the form of adults or larvae.
• Native species may be more susceptible to the exotic disease
• These exotic species can interbreed or out compete the native species and destroy the natural stocks.
Disease and diagnosis
Decreased production
Sub-clinicaldisease
Clinicaldisease
When disease is present,
only a small part of the population
usually shows clinical disease
Carriers
Knowing a Pathogen is Costly
• distribution (how contagious it is) • duration of infection (will it kill the whole stock?)• survival time outside the host (does it incubate
or hide somewhere?)• ability to multiply and remain viable in water• environmental fate • number of infectious units required to cause
infections and pathogenicity• host specificity to determine if cross species
infections or disease are likely to occur• development of immunity
Disease avoidance approaches
• No introduction
• Inspection at source
• Inspection upon entry
• Quarantine
• Introduction of stock known to be clean
Biosecurity is a problem!
The tiger is our own!
Why lose it?