killer disease?

In addition, researchers led by Thawatchai Chaijarasphong say that the existence of EHP is also triggered by the high density of shrimp which has been widely applied across Asian countries since the early 2000s. While Zhang adds that EHP is also triggered by blooming algae and pH fluctuation .

Prevention is always a wise action

As common as how to treat the disease in the shrimp farm, minimizing EHP is also better by preventive action. The first step can be done by ensuring the shrimp PL of the shrimp is free from EHP after PCR or microscopic testing. And then implementing strict biosecurity, best practices, and optimizing water quality are necessary.

Because EHP can be transmitted vertically, the prevention ideally should not only be carried out in grow-out ponds but should start from the broodstock maturation and spawning processes. One of the gates which EHP can enter is the fresh or live feed of broodstock such as polychaetes and bivalves. Researchers suggest that before it is used, the fresh feed must be treated with thermal shock by freezing it at -20 degrees Celsius for 48 hours. Or by heating it at high temperatures.

“However, a far better treatment would be to hold them at 70 °C for 15 min (pasteurization) since this would kill not only EHP but also the other major bacterial and viral pathogens of shrimp if present. It is probable that pas- teurization would reduce the yield of nauplii from the broodstock, but we believe that this cost is justified to remove the otherwise high risk of pathogen contamination from such feeds.” the researchers state in the journal.

Meanwhile, in the transition between the hatchery and grow-out pond, the shrimp PL should be confirmed free of EHP by PCR screening. But it’s worth noting that an EHPfree statement from the hatchery doesn’t mean the farmers no need again to check shrimp periodically after stocking into the ponds. And the sampling would be better by using molecular methods to ensure whether EHP existed or not.

If that periodic sampling shows in early EHP detection or if HPM is suspected, the manager of the pond can minimize the horizontal spread by several actions. Namely by reducing shrimp density, increasing water exchange, removing feces, then removing and burying the dead shrimp before it is eaten by another shrimp.

Besides applying common best practices, Erwin Budiman has his own way of EHP prevention. Based on his experience, he encourages fellow farmers to apply nursery or multiphase systems to minimize EHP. This method has been quite good because the seed stocked into grow-out ponds are already larger, around DOC25 or PL35, which are also relatively stronger.

THE CRUST has discussed the benefits of the nursery in minimizing EHP, particularly if using small and round tanks. This system can reduce EHP outbreaks as it can control effluent easily through shrimp toilets or central drains.

Meanwhile, from a nutritional perspective, Mr. Zhang from Haida said that there is no research so far on the use of certain ingredients or feed additives to inhibit EHP. However, good quality feed with high protein and digestibility can help the shrimp’s resistance to EHP infection.

Last but not least on how to prevent EHP, farmers can also use quicklime (CaO) during preparation. Researchers write that CaO can stimulate spore germination and inactivation to reduce infection pressure. Let alone if the pond was hit by EHP previously. Zhang says that this method is also used by farmers in China. “They will make sure the pond is free from EHP before stocking the shrimp,” Zhang says.

Markets have been quiet over the holidays. One major change has been the opening of China to the world where Chinese can once again travel without the need for approval from the government. Many have speculated that the timing for this has been rather deliberate by the Chinese government, coinciding it 2 weeks before Chinese New Year to get the peak number of cases over before then.

However, there is also a secondary effect on the market. Typically, the highest consumption of shrimp in China is during the Lunar New Year. This year’s Lunar New Year also happens to be rather early which means that stocks of shrimp arriving from Ecuador should have sailed in late October or early November at the latest. There will be no more last-minute panic buying. What has been sold should have been sold.

Hence, we are seeing prices of Ecuadorian shrimp barely move. Last week Ecuador was quoting at:

20/30 6.30USD/kg

30/40 5.59USD/kg

40/50 5.30USD/kg

50/60 4.90USD/kg

This is a bare 10 cents increase in size 30/40. Many could say however that this is just