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?