Revival of the monodon shrimp with high health post larvae

The bottom line are checks for disease-free wild broodstock and a 2-week quarantine of spawners prior to introduction into maturation tanks

There are two concurrent projects on Penaeus monodon or black tiger shrimp in India, both conducted by the Rajiv Gandhi Centre for Aquaculture (RGCA), the R&D arm of the Marine Products Export Development Authority (MPEDA). In 2005, well before the arrival of the Pacific white shrimp Penaeus vannamei in 2009, which ultimately dominates shrimp farming in India, RGCA started a domestication and breeding program of P. monodon at Kodiaghat and Amkunj in the Andaman and Nicobar Islands. The project is in its ninth generation to produce specific pathogen-free (SPF) monodon broodstock.

The other is a more recent maturation and hatchery facility in the Multispecies Aquaculture Complex (MAC) on Vallarpadam Island, Kochi, Kerala. The purpose is to produce disease-free monodon post larvae. This production uses wild caught broodstock collected from all over India. The aim of the latter project is to kickstart the revival of monodon shrimp farming, the production of which is around 50,000 tonnes/annum, as compared to almost 750,000 tonnes of the vannamei shrimp in 2019.

RGCA Project Directors, Dr S. Kandan and Dr T.G. Manojkumar, who is also the Project Manager at MAC, are excited with the recent interest shown by farmers to revive the farming of the monodon shrimp. “I am very convinced that with good quality post larvae, this shrimp can make a comeback. Here we have a capacity for only 20 million post larvae (PL12-PL20), but the current bookings have already reached 24 million post larvae,” said Kandan.

One of the major constraints in the development of specific pathogen-free (SPF) monodon shrimp in the Andamans has been the infectious IHGS (Idiopathic hyaline granuloma syndrome) and SMV (spawner mortality syndrome), which is apparently endemic to local populations (Luna, 2013). Recently it was found that with the progression of the generations some resistance to IHGS was noticed, according to Manojkumar.

Water treatment is an important prerequisite for this hatchery. Here seawater of 30-34ppt is drawn from the nearby creek. It passes through a micro sand filter before being channelled to a reservoir where chlorine (20ppm) is added, followed by 20 minutes of aeration. After 12 hours, the supernatant water is channelled to

another reservoir for de-chlorination with sodium thiosulphate. Water flows to another reservoir for ozonation, sand and carbon filtration, before passing through a one micron cartridge filter and Larval tanks finally UV treatment, before being used in the hatchery.

Strain differences of wild broodstock

At the hatchery, Manojkumar said that they collect spawners from all over India. He noted that there are strain differences between monodon shrimp caught in the east and west coasts of India. In fact, they also saw strain differences between shrimp caught in different locations in the east coast, such as in Visakhapatnam, Paradweep and Pazhayar. Similarly, differences are noted between shrimp caught in various locations in the west coast. “Dr D Lightner informed us to expect differences in shrimp from locations even 200-300km apart. Differences noticed

included growth. One family showed much slower growth and also very pale colouration. We see the growth equalising with that of other families only after 120 days as well as tolerance to IHGS.”

Disease-free-broodstock

All broodstock are quarantined and tested for 15 disease pathogens, the 7 OIE pathogens (white spot syndrome virus (WSSV), Taura syndrome virus (TSV), yellow head virus (YHV) and gill associated (GA) virus, infectious myonecrosis virus (IMNV), infectious hypodermal and haematopoietic necrosis virus (IHHNV), hepatobacter penaei (NHP-B) and acute hepatopancreatic necrosis disease (AHPND). The additional eight are Enterocytozoon hepatopenaei (EHP), covert mortality nodavirus (CMNV), monodon baculovirus (MBV), hepatopancreatic parvo virus (HPV), shrimp haemocyte iridescent virus (SHIV), Laem-singh virus (LSNV), spawner associated mortality virus (SMV) and rickettsia-like bacterial disease (RLB).

“Only when they are free of these diseases, do we bring them over to the hatchery for the maturation process and spawning. We then cross a female from one region with a male from another region. In 2018, we found some interesting results from these crosses. We will be revealing the results soon but I can tell you that some crosses have revealed fantastic results. A farmer said that in all of his 16 years of farming the monodon shrimp, he has not seen such fast growth, shrimp reaching 25-30 pieces/kg in 86 days. We attribute this to crossing different strains and elevating genetic vigour,” said Manojkumar.

The supply of high health post larvae to farmers began in February 18, 2019. Kandan said, “Our post larvae have a very good reputation. Farmers call them ‘Vallarpadam post larvae’. Our next target is to set up private hatcheries all over India. We have received requests from the state government of Gujarat and Andhra Pradesh. I am very convinced that if good quality post larvae are available, the monodon shrimp will make a comeback.”

Published in May/June 2020 AQUA Culture Asia Pacific Magazine