8/8/2019 A573 Super Intensive Shrimp System Provides a Look Into the Future

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Producing more than nine kilograms o Paci c White Shrimp percubic meter, a research team led by Dr. zachi Samocha at exasAgriLi e Mariculture Research Laboratory in Corpus Christi, exasis orging a path that could allow producers to thrive in spite o therazor-thin margins o the shrimp market.

he team’s super-intensive shrimpproduction system relies on precisemanagement, high biomass, andbiosecurity to stimulate outstandinggrowth and drive production costsdown rom above $5.00 per pound – thecurrent U.S. average or superintensivesystems – to approximately $2.00 perpound. he three-month grow-outperiod allows nearly our crops per tankper year. Coupling those productione iciencies with sales to high-value

resh or never- rozen regional marketscould make shrimp pro table to many growers again, says Samocha.

Samocha’s indoor, limited-discharge,super-intensive system is stocked at 530shrimp per cubic meter, a radical departure rom the conventionaloutdoor ponds raising 100 to 150 shrimp per cubic meter. But

high-intensity production demands high-intensity management,especially because the system’s dissolved oxygen (DO) levels aremarginal at best – and they drop precipitously at eeding time.

“We’re always on the borderline, pushing the envelope on DO,” saysaquaculture technician im Morris in Samocha’s lab. “When we add

eed, you can literally watch the DO drop. In 30 minutes, you’ll seeit go rom 4.5 milligrams per liter (mg/l) to 3.5, or rom 4.0 to 3.0.You ride the balance between li e and death.”

Tose rapid declines, and the slow DO recovery to sa er levelsa er eeding, demand care ul scrutiny. It is also vital to maintain

constant track o DO levels to determine whether pumped air willbe adequate to restore DO, or whether more costly liquid oxygen isnecessary. In the super-intensive system, every liter o oxygen cana ect survivability – and pro tability.

Limited-Discharge RacewaysTough they are called raceways, the our greenhouse-enclosed,40-cubic-meter tanks in Samocha’s trial are not raceways in theclassic sense, as there is no inlet or outlet. Water is retained in thesystem to avoid introducing pathogens through intake water and

Y S I Environmental

Super-Intensive Shrimp System Provides A Look Into The Future

incurring environmental costs at the discharge. Municipal wateris added to replace water lost to evaporation, approximately onepercent o the total volume per day.

Managing oxygen is the cornerstone o the operation. Each racewayis equipped with a series o eighteen 5.1cm airli pumps, six one-meter-longair di users, and a partition runningdown the centerline to keep watercirculating in the proper direction.Under the partition, a 5.1-cm PVCpipe is positioned to deliver air roma Venturi injector powered by a 2-hppump.

Remarkably, Samocha and his teamsupplied the system’s oxygen needs withatmospheric air and the Venturi injectorsuntil biomass reached approximately 7

kg/m3 on Day 73. On Day 74, the teambegan enriching atmospheric air withliquid oxygen at an average o 3.5 literper minute (lpm) or the remaining 20days o the study.

he raceways are heavily colonized with bacterial locs and

microalgae in the limited-discharge environment. Te bacteriacontribute to high solids in the water – the team’s target or totalsuspended solids ( SS) was 500 mg/l.

“Te bene ts you get rom the bacterial focs are stability o waterquality and contribution to shrimp nutrition,” says Samocha. Tebacteria assimilate nitrogen compounds that can be harm ul toshrimp, he explains. Furthermore, initial indications suggest thatthese bacteria may also be used as a source o eed or bio uel, hnotes.

Unlike algae, the bacteria constantly consume oxygen rather than

produce it. Tese bacteria do not create major daily shi s in DO,adds Morris. “With bacterial focs, you don’t see the huge diurnalfux that you see in outdoor production systems,” he explains. “Teshrimp like that. Tey can deal with these DO levels o 4.0 as longas they’re constant. In an algae-based, green-water system, DOs aretypically nice and high during the day, when the sun is out. But at4:00 every morning, they can go down to 2.0. When it does that day a er day, it’s stress ul or the shrimp.”(continued)

Application Note

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These 40-cubic-meter raceways do not discharge water during the 3-month production cycle.

Bacterial focs help stabilize water conditions,assimilate nitrogen compounds, and provide

nutrition or the shrimp. [Photo: Tzachi Samocha]

8/8/2019 A573 Super Intensive Shrimp System Provides a Look Into the Future

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Constant MonitoringTe team analyzes water samples weekly or alkalinity, settlablesolids, turbidity, algal counts, total suspended solids ( SS), volatilesuspended solids (VSS), carbonaceous biological oxygen demand(cBOD), ammonia, nitrite and nitrate-nitrogen, and reactivephosphorus.

But oxygen management can’t wait a week. Duringthe early stages o production, DO and pH aremonitored at least twice daily with handheldinstruments. As the shrimp grow, water quality decreases and oxygen demand increases. At around30 days into the production cycle, Samocha’s teamdeploys YSI 5200 continuous monitors, whichthey set to log DO and temperature readings at

ve-minute intervals and trigger an urgent alarmon their computer monitors i levels drop belowchosen thresholds.

“It’s very crucial that you stay on top o things andmodi y your management accordingly,” cautionsSamocha. “I oxygen is low and you are dumpingin eed, I can guarantee within a ew minutes youwill have stressed shrimp at the sur ace. I youdon’t have this monitoring system, it is very risky

or your production.”

Morris positions the probes o the YSI 5200 monitor in ront o airli s to ensure a steady fow o water over the sensors, reducingbio ouling. In the nutrient-rich water, wiping the probes occasionally is still important to keep them clear o bio lm.

Darrin Honious o YSI in Yellow Springs, Ohio, points out that theYSI 5200 – which can simultaneously monitor temperature, DO, pH,conductivity, oxidation-reduction potential (ORP) and salinity – isdesigned speci cally or the punishing conditions o aquaculture. Inaddition to continuous monitoring and alarms through audio signals,emails and even phone alerts via a hookup with a Sensaphone®remote monitoring system, the 5200 can also be programmed tocontrol pumps, paddles, liquid oxygen valves and eed systems.

Samocha’s team uses YSI’s AquaManager M so ware to record anddisplay the data rom the 5200s. Morris says the system allows him

to not only monitor the system in real time at the lab and remotely rom his home computer, but also to track trends over hours and

days. Tat’s vital, especially because the super-intensive productiontanks periodically experience slow downward trends in DO.

“Te monitoring system allows me to act be ore something happens,rather than react to an emergency situation,” Morris says. “It takes alot o the guesswork out. We can start planning ahead.”

Honious predicts that as super-intensive shrimp systems gocommercial, producers will take even more guesswork out othe equation by utilizing the automation capabilities o the 5200,including managing DO and temperature as well as conditional

eed timing, which actors in biomass, ee

conversion ratio and environmental conditionswhen electronically engaging eeders.

Fine DetailIn act, one o the most signi cant adjustments thathas arisen rom continuous, real-time monitoring o the system is the ne-tuning o the eed regimen.

Until Day 56 in the study, the shrimp were ed ourtimes daily, at 8:30 and 11:30 am and 2:30 and 4:30pm. When biomass reaches 6 kg/m3 and DO dropstoo precipitously a er eeding, the our daytime

eedings were cut back to one-to two-thirds o thetotal ration, with the remainder metered out at nightwith belt eeders.

In the end, Samocha’s system yielded an impressiveaverage eed conversion ratio as low as 1:1.2 and aweekly gain o 1.3 g/week to produce as much as

9.23 kg o marketable-sized shrimp per cubic meter. Te closedsystem success ully prevented viral outbreaks, and mortality washeld below 0.5 percent per week.

Samocha and his team penciled out the economics o a year-round,commercial installation o the super-intensive, limited dischargesystem. Assuming the operation built eight 500m3 grow-out tanksand two nursery tanks to produce an average o 3.8 crops per yearwould cost USD$992,000, they gured. At a price o $3.27 per pound

or 21-to-25-count shrimp and production costs around $2.60, thesystem could pay itsel o in about 3.1 years and deliver an internalrate o return o more than 28 percent. And without the regulatory challenges and the cost o discharging and replacing water, the systemhas extra appeal in the tightly regulated U.S. market.

Tat paints a bright uture or super-intensive shrimp production.And with skilled operators and reliable, continuous monitoring andcontrol, it gets brighter and brighter.

For additional in ormation including YSI instrument specifcations, pleasevisit: www.ysi.com/aquaculture

Tel.+1 937 767 7241US 800 897 4151environmental@ysi.comwww.ysi.com/aquaculture

Y S I Environmental Application Note

0509 A573©2009 YSI Inc. +1 937 767 7241 Fax +1 937 767 9353 environmental@ysi.com www.ysi.com/aqu

Each raceway was equipped with a YSI 5200 continuous

monitor, logging DO and tem-perature every 5 minutes.

Pure Data for a Healthy Planet.®