Can genetics breathe new life into giant river prawn production?

Glen Illing and Willem van der Pijl at the Global Shrimp Forum

So says Glen Illing, partner at Aqua Woowho gave a talk on the species at the recent Global Shrimp Forum in Utrecht.

According to Illing, the reasons for the current stagnation in the giant river prawn sector include the species’ relatively low profitability compared to monodon and vannamei prawns.

“The species is grown at relatively low stocking densities, often as a secondary crop and – quite frankly – the second choice crop, favored overall by small subsistence farmers. If profitability can be improved, the Freshwater prawn farming will increase and that’s where genetics can play a role,” he said.

“Genetic improvement is synonymous with efficiency, profitability and disease resistance,” he added. “But it baffles me why it is so poorly applied to a species with so much potential as the giant freshwater prawn and yet it has been applied to other species such as the vannamei, where there have been massive leaps and improvements since the year 2000.”

This is all the more surprising since, according to Illing, the researchers have laid down some of the essential foundations.

“There have been notable events [breeding] programs and also some large research projects, but they have not been integrated into the traditional production of jumbo freshwater prawns,” he observed.

“There are woefully few breeding programs that actually apply genomics to giant freshwater prawns,” he added.

Although there have been a handful of successful breeding programs in countries like Indonesia, China, Vietnam, Thailand and India, Illing noted that the benefits from generation to generation have since slowed, in largely due to problems caused by inbreeding.

jumbo river prawns
Modern genomic techniques rarely make their way into giant river prawn breeding programs

Unmixed stocks

One development Illing sees as having great potential is the use of genomics to produce all-male and all-female stocks – the former are bred to large sizes over long cycles to compete for the lobster market, while the latter can produce three cycles per year.

“Both gender-focused programs increase profitability compared to mixed culture, and both can be used in polyculture with vannamei or with fish like tilapia,” he said.

“Relatively large proportions of freshwater shrimp farmers are starting to rear only males, especially in Thailand…on the other hand, the all-female revolution is taking longer to reach large-scale production, this technology is currently protected by a patent and developed exclusively by a company [Enzootic],” he explained.

More recently, Illing argues, the rise of gene editing “can bypass most backbreaking quantitative genetic work” and “will come much faster than people imagine.” And he highlighted a number of breakthrough technologies, including one to Ben-Gurion University who developed “specifically designed platforms to be able to edit freshwater shrimp”.

Enzootic’s all-female production

Illing then focused on Enzootic’s all-female jumbo shrimp production work. Although the company is based in Israel, it recently built a compact, vertical RAS hatchery, with the capacity to produce 450 million giant river prawns per year, near Bangkok – one of the main production areas for giant prawns. fresh water. Here they are grown to juvenile size before being shipped to farmers.

“The crux of all-female production is the ability to increase stocking rates in ponds or reservoirs at economic densities and achieve desirable market size in four months to enable three cycles per year and maximize yields of farmers. Operating at economic density is key – too high and the management challenges are insurmountable, too low yields would not economically justify the costs,” Illing observed.

Trials undertaken by the company should soon establish the best stocking densities on commercial farms. But Illing also pointed to the results of a tank test undertaken by the Asian Institute of Technology (AIT) found that optimum yields were around 24 giant river prawns per square meter, while the fastest growth rate occurred at 8 prawns per square meter – compared to the 4 per square meter favored on traditional farms.

jumbo river prawns
New research trials hope to establish best storage densities for commercial environments

© Gregg Yan

The next question Illing would like to see answered is whether the results of these pond trials are warranted in commercial all-female production pond production.

And, to speed up the process and encourage farmer buy-in, Enzootic has established a large-scale commercial farm east of Bangkok, consisting of 55 earthen ponds over 100 ha. The first harvest of these is expected soon, he noted.

The company is also pursuing its vertical integration approach by developing a branded product, which is currently being tested in the high-end retail market in Canada.

Rob Flecher

Editor-in-Chief at The Fish Site

Rob Fletcher has been writing about aquaculture since 2007, as editor of fish farmer, Fish farming specialist and The fish website. He holds an MA in History from the University of Edinburgh and an MA in Sustainable Aquaculture from the University of St Andrews. He currently lives and works in Scotland.

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