Test pro-actively with prevention in mind.
At hatchery check breeders and history to align with your requirements.
At farm level look at incoming PL’s history.
Use the salinity stress testing we developed in the mid 1980’s and explained here as a practical guide in the field.
Do not believe marketing propaganda, like the one below that tells you things like :
“The most important quality factor for shrimp PL is not detectable by either visual exam or stress test. It is whether the PL are free of listed pathogens (such as WSSV, TSV, IHHNV etc).
Clean PL (i.e. SPF) can be determined two ways: 1. By PCR screening which is expensive, highly variable and therefore ultimately unreliable or 2. Buying from reputable supplier who uses certified SPF broodstock. HHA Inc.”
Clean SPF PL’s are not of any use if your culture and husbandry systems are not well managed.
SPF’s program’s failed in the case of Ecuador but of course pathogen testing is a good move at hatchery level – pretty useless at farm level as the cure is prevention and corrective action is nigh on impossible.
With bio-security, water quality, feed quality and husbandry being more important.
Forensically it is not that hard