14 Shrimp Culture
Black tiger shrimp: Better or Blunder The pull for a return to its farming is the availability of SPF broodstock but a concern is competition with the large vannamei shrimp
Harvested monodon shrimp in September 2021
B
ack in 2014, Dr Manoj M Sharma, Director at Mayank Aquaculture Pte Ltd (MAPL) came to the TARS conference to explain his way to farm Penaeus vannamei, the monodon way, producing large size shrimp (40-50g) at low stocking density of 15-20 PL/m2 in Gujarat, India. This year Manoj has reverted to farming black tiger shrimp (Penaeus monodon) which became possible with the recent availability of post larvae from specific pathogen free (SPF) broodstock in India. As a longtime advocate of farming the monodon shrimp, given the right conditions, Manoj decided to test whether “bringing back the black tiger shrimp is better or a blunder” for him. During TARS 2021, he discussed his reasons for bringing back monodon shrimp production although there is concern on its export potential. SPF and domesticated monodon broodstock are now available in the region, which Robins McIntosh, CPF, Thailand referred to as the push for the successful expansion of monodon farming in China, Malaysia and Vietnam. Dr Tung Hoang, CSIRO, Australia said that Vietnam produces 250,000 tonnes of monodon shrimp annually using extensive culture models where stocking at 0.5 PL/m2 produces 100g in 90 days and stocking at 1 PL/ m2 produces >100g shrimp in >120 days.
For Manoj, farming monodon in bio-secured farms using the present vannamei model should not be a problem. However, there is a need to keep a close watch on monodon growth and survival, as the carrying capacity of farms has been severely reduced due to repeated vannamei shrimp farming. When vannamei shrimp farming began in Asia, it was supposed to occupy the smaller size (100/kg to 50/kg) shrimp market but gradually, with partial harvesting, it can now occupy all size segments. Therefore, it is essential that he and other farmers understand the market for the monodon shrimp.
History of the monodon shrimp in India
In India, shrimp farming started with its endemic monodon shrimp from 1985 to 2009, until the white spot syndrome virus (WSSV) devastated production, from its peak of 120,000 tonnes in 2005 to less than 80,000 tonnes in 2008.
November/December 2021 AQUA Culture Asia Pacific
“Back then, our biggest limitation was the quality of both broodstock and post larvae. We had repeated diseases; WSSV, loose shell, hepatopancreatic virus (HPV), poor growth and external fouling with slow growth. To reach 30 count/kg took 150-200 days. We were desperate until farming of the vannamei shrimp was allowed and the biggest highlight of this was the availability of SPF/ SPR (specific pathogen resistant), disease free and high health broodstock.” Manoj added, “Of course the attraction was the size range accepted by markets and that production can extend to 10 tonnes/ha.” In India, vannamei shrimp farming began in 2010 and since then, production has been phenomenal. In 2020, 95% of production was vannamei shrimp from 75 billion post larvae. Today, there is hardly any supply of monodon post larvae. “We reached 800,000 tonnes in 2019 and the 20% decline in 2020 was definitely due to production issues as much as the Covid-19 pandemic.”
Increasing costs of production
The problems with vannamei shrimp farming range from lower survival rate to slower growth, higher feed conversion ratio (FCR) and rampant disease outbreaks from Enterocytozoon hepatopenaei (EHP), Vibrio, atrophy of hepatopancreas, running mortality syndrome (RMS) in 5-10g shrimp, white faeces disease (WFD) and more recently, infectious myonecrosis virus (IMNV). WSSV remains the biggest threat with 50-60% of farmers reporting the disease, especially during the postmonsoon season. With the pandemic, disruptions led to drastic increases in costs. In the last three months (since May 2021), shrimp feed prices have increased 8-12%. Manoj listed issues such as high stocking density and high salinity compounded with high organic load as the recipe for disaster in shrimp farming. It was not only production versus pond carrying capacity but also production area versus water source carrying capacity (Sharma, 2019). “I call this whitewashing in shrimp farming - in summer, it is WFD and in winter and monsoon season, WSSV!”
