Diseases and pathogens move across borders, and lessons from Vietnam, Nigeria, and Ecuador all carry warnings for Indonesia. By looking at the global picture, Melony Sellars, CEO of Genics, at FARM 2025 in Jakarta, urged farmers to act locally with stronger biosecurity practices.
Disease is the single greatest cause of loss in shrimp farming worldwide. From WSSV to EHP and AHPND, pathogens and the diseases they cause have become unwelcome but common players in aquaculture. What makes the issue more complicated is that Indonesia, like Brazil, faces the additional threat of IMNV, putting the country in a particularly vulnerable position with four commercially devastating pathogen agents, some of which occur as multi-factorial infections.
She explained that pathogens spread in multiple ways. Six key pathways are especially relevant in Indonesia, including infected broodstock from being fed wild-caught polychaetes, shared equipment between farms, translocation of contaminated post-larval shrimp, carryover from previous crops, water intake that is not properly treated and roaming animals. Each of these pathways may seem small in isolation, but together they represent a significant risk.
A real-world example illustrated the urgency. In Vietnam, a testing laboratory issued a negative test report on broodstock that was then exported to Nigeria. The shrimp were later found to carry infectious viruses, forcing quarantine and culling. This was the result of a false-negative test result from a PCR Laboratory in Vietnam. In this case, Melony said, biosecurity is shown to be a shared responsibility. Farmers cannot rely only on regulations or paperwork. They must demand high standards from their suppliers and ensure that every step is verified.
Melony emphasized the importance of statistically significant sampling. Too often, farmers receive pathogen-free certificates that mean little in practice because the sampling was too few of the total population. She compared it to testing only a handful of people in a crowded room for COVID. Unless the sample size is large enough, the results may suggest safety when, in fact, infection is present. For farmers in Indonesia, this means insisting on suppliers who conduct statistically significant sampling and use PCR testing that is scientifically validated to be fit for purpose. Without this, false negatives will continue to slip through, putting entire crops (and countries) at risk.
She also urged caution when interpreting wet mounts and bacterial plates. Farmers often believe they are detecting Vibrio or EHP, but these traditional methods are no longer reliable. Advanced technologies like MultiPath PCR provide far more accurate results, detecting pathogens even in the early incubation stages. For Melony, relying on outdated methods is like trying to navigate the sea with an old map that no longer reflects the currents and reefs.
Figure 1. Indonesia, like Brazil, faces the additional threat of IMNV, putting the country in a particularly vulnerable position. Credits: Melony Sellars
Smarter practices
Prevention is always more effective than cure, and biosecurity is the number one defense. At the farm level, this means controlling access, disinfecting equipment, ensuring water is properly treated, and preparing pond liners carefully between crops, said Melony. Farmers should test pond sediments and harvested shrimp to identify pathogens before restocking, adjusting pond preparation accordingly. In many cases, simple practices such as proper liming or repairing pond liners can save money and prevent major losses.
She spoke about the role of water management, noting that chlorine, UV, and ozone systems must be operated correctly to be effective. Too often, farmers install these systems but fail to maintain them or measure their effectiveness. A UV lamp that is not calibrated, or chlorine stored under the sun, becomes little more than a false sense of security. She encouraged farmers to test their systems before and after treatment, using sensitive, accurate (fit-for-purpose) PCR to confirm that pathogens have truly been eliminated.
Another major issue is the use of wild-caught polychaetes in broodstock feeding. Even when shrimp are certified pathogen-free, feeding them with infected polychaetes reintroduces the very risks farmers are trying to avoid. Melony urged farmers to demand broodstock that are raised with pathogen-free feeds, describing this as one of the biggest breaches of biosecurity in the industry.
Looking beyond the farm, she spoke about the importance of national and global cooperation. Diseases do not respect borders, and Indonesia is part of a worldwide network of shrimp production. That is why transparency, shared data, and continuous education are critical. She praised Indonesia’s supply of clean SPF broodstock and SPF post-larvae from specialized local producers in Bali, but also warned that the system must be protected from complacency.
Melony highlighted new approaches, such as nursery rearing systems that can give shrimp a head start before entering grow-out ponds. She also spoke about microbiome analysis, a modern tool that helps farmers understand the bacterial communities in their ponds and validate whether probiotics and water treatment systems are truly effective. These innovations, she said, can help farmers move from reactive to proactive management, reducing risk and improving profitability.
The key takeaway from her is that biosecurity is not a one-time checklist but a continuous process of improvement. Every farmer, hatchery, supplier, and regulator have a role to play. When a shipment is rejected or a disease spreads, the damage is shared across the industry. But when biosecurity is strengthened, the benefits are also shared, from healthier shrimp to stronger market trust.
