1. Introduction
With the world population increasing and climatechange putting pressure on the supply of crops,
food security is increasingly threatened while
demand for fishery products is on the riseworldwide. World fishery production, however,has been hovering around 90 million tons in thelast 20 years. In particular, marine production issaid to have reached its limit. Aquaculture
production, therefore, is growing at home andabroad to compensate for the production of highdemand fishery products1. Among others, shrimp
culture, which is more feed efficient than livestock
farming (cattle, hog and poultry), is receiving
growing attention in landlocked developing
countries faced with food shortages. At the sametime, shrimps are growing in significance as asource of animal protein. World shrimp production
has been increasing in recent years (Figure 1); it
stood at about 3.8 million tons in 2010, 71.8% of
which were white shrimps2. White shrimps are theworld’s most successful species in theaquaculture industry, with 77.9% produced in Asia.

Intensive shrimp culture is common in Southeast
Asia, where fries are released into large artificialponds and fed intensively with compound feeds.
The excrement and leftovers, however, aredeteriorating the cultural environment while thewastewaterispollutingthesurroundingenvironment.
Shrimp culture has been repeatedly damaged by theprevalence of diseases. For example, EMS (EarlyMortality Syndrome), which results in the massmortality of fries3, began to become widespread in
China in 2009 and has been reported in someSoutheast Asian countries (Figure 2)4,5. In particular,
Thailand has been the hardest hit, where shrimp
production plunged from 600,000 tons in 2011 to300,000 tons in 2013. As a result, the international
market price of white shrimps at the end of 2013
almost doubled from 2012 levels, which also had an
impact on the Japanese market. Shrimp pond water
should therefore be purified with its quality stabilized
to prevent diseases like EMS and to increase theproductivity of shrimp culture.

Cultivated production（t）

4,000,000
3,500,000
3,000,000
2,500,000
2,000,000
1,500,000
1,000,000
500,000

Figure 1. World aquaculture production of shrimp

2010

2005

2000

1995

1990

1985

1980

1975

1970

1965

1960

0Figure 2. Geographical distribution of (EMS/AHPND)
in the world1

Taiheiyo Cement Corporation set up the Aqua
Business Group in the Environmental Business
Development Department in October 2012 todevelop and commercialize water treatment
materials, working on technologies to improve theaquaculture environment. This report concerns theuse of the water quality stabilizer Ceraclean for an
improved shrimp culture environment, the summaryof which is given below, along with its development
status.

2. Overview of water quality
stabilizer Ceraclean
Ceraclean (Picture 1), an artificial calcium silicate
hydrate with numerous micropores, is designed toimprove pond water quality. Consisting primarily ofa mineral called tobermorite, it stabilizes pH andalkalinity with its strong buffering capacity, withuseful bacteria growing in the pores (Picture 2).
While the excrement and leftovers accumulate on
the bottom of shrimp ponds, causing water pollution,
Ceraclean helps useful bacteria grow, which in turn
reduces the amount of sludge and purifies thewater. It’s being marketed in Taiwan for use
primarily in shrimp culture. In addition, R&D isunder way on its other properties to boost its sales
and develop new markets in Southeast Asia andother parts of the world.

5mmPicture 1. Ceraclean

3. Development history andstatus
3.1 Review of the increase in the productivityof shrimp culture
The authors, Tokyo University of Marine Scienceand Technology and Walailak University in Thailand(where shrimp culture is widely practiced), launcheda joint program in 2013 to study the effects andmechanism of Ceraclean for use in shrimp culture.
First, white shrimps were kept in tanks at Walailak
University for laboratory experiments, where tests
were conducted with four parameters on two groups– with Ceraclean (application of 60mg/L every threedays) and without Ceraclean (control). Specifically,
350 L tanks were used for 60-day feeding, with eachcontaining 20 white shrimps, to determine theaverage daily growth (hereinafter, “ADG”) andsurvival rate. Table 1 shows the growth and survival
rate of the shrimps after 60 days. The ADG, withCeraclean applied, was 0.02g higher compared tothe control, which proves its effectiveness in
improving the growth rate. Likewise, the survival
rate increased by 24.2%, resulting in a 95%
increase in the yield, which suggests the potentialfor a significant increase in the productivity. To shedlight on its mechanism, calcium eluted from
Ceraclean was measured in terms of its
concentration in the tank water; it stabilized between
300-400mg/L (see Figure 3) while the calcium
concentration in the control fluctuated significantly,
followed by a gradual decrease. Calcium is an
essential mineral that helps shrimps grow healthily
and form their shells, which could increase theirresistance to diseases and survival rates. Picture 3
shows how the tank water looked; the control turned
green while that with Ceraclean applied, turnedbrown. Microscopic examinations found the growthof green algae (such as toxic dinoflagellates) in thecontrol and of diatoms (rich in unsaturated fatty
acids, serving as nutrient sources for shrimps) in thewater containing Ceraclean. A continuous supply ofsilicate eluded from Ceraclean (an essential nutrientfor diatoms) may have contributed to the steady
growth of diatoms.
Table 1. Effect of Ceraclean on growth and survival
rate of white shrimp (60 days)

Tobermorite（ Platelet crystal ）Picture 2. SEM images of Ceraclean

Nanoporous

Parameter

Control

Ceraclean

Initial weight (g)2.37 + 0.35

2.35 + 0.38

Final weight (g)6.07 + 1.29

7.28 + 1.30

Weight gain (g)3.71 + 1.30

4.74 + 1.26

ADG

0.06 ± 0.02

0.08 ± 0.02

Survival (%)

37.5 ± 20.6

61.67 ± 17.6

2

CO2Feed（C, N）

Added
Carbohydrate

ResidualFeed
Excrement

Non Utilized

NO3

C, NH4Microbial growth

Figure 4. Scheme of Biofloc technology system
Figure 3. Effect of Ceraclean on Calcium in waterof white shrimp culture

Green algae(Nannochloropsis spp.)

ControlDiatom(Chaetoceros spp.)

Ceraclean

Picture 3. Color of water and types of algae in tanks

3.2 Effects of Ceraclean associated with
Biofloc technology
A shrimp culture technique called Biofloc technology
is gaining attention in South Korea, Thailand andother parts of Southeast Asia. Biofloc technology
involves the use of artificially flocculated bacteria(Biofloc) that reduce the amount of ammonia andnitrous acid (toxic compounds produced from theexcrement and leftovers) in the culture water.
Biofloc itself serves as a source of protein forshrimps6. Other effects for shrimp culture include:
appropriate turbidity controls that reduce stress andcannibalism; establishment of a stable biota tomaintain the water quality and prevent the intrusionof pests; and production of diatoms to feed shrimps(Figure 4).
As the results of the laboratory tests above suggestthat Ceraclean helps diatoms propagate steadily,scaled-up tests were conducted subsequently, giventhat the combination of Ceraclean and Biofloc
technology is expected to increase the productivityof shrimp culture. Specifically, the tests wereconducted with four parameters on four groups –with Ceraclean, with Biofloc, with Ceraclean andBiofloc, and the control – using 500L tanks for 60day feeding, with each containing 60 white shrimps;
Ceraclean was applied every 7 days at aconcentration of 60mg/L. Table 2 shows the growthand survival rate of the shrimps after 60 days – both
the ADG and the survival rate were highest in thegroup with Ceraclean and Biofloc, showing a 0.02g
increase and an 18% increase, respectively,compared to the control. Ceraclean, therefore,contributes to further increasing productivity whencombined with Biofloc technology.
Table 2. Effect of Ceraclean on growth and survival
rate of white shrimp (60 days)
Parameter

Control

Ceraclean

Biofloc

Ceraclaen+BioFloc

Initial weight (g)1.65 + 0.07

1.47 + 0.09

1.80 + 0.25 1.47 + 0.09

Final weight (g)6.45 + 0.10

6.87 + 0.49

7.20 + 0.70 7.52 + 0.42

Weight gain (g)4.8 + 1.30

5.4 + 0.26

5.43 + 0.70 6.05 + 0.63

ADG

0.08 ± 0.01

0.09 ± 0.01

0.09 ± 0.01 0.10 ± 0.01

Survival (%)

63.5 ± 9.774.5 + 1.2

77.1 + 5.1

81.5 + 3.4

4. Overview
The above is a summary of the water quality
stabilizer Ceraclean and its development status.
Because of their high feed conversion efficiency,
shrimps are expected to play a crucial role indealing with the food crisis while in Southeast Asia,
where most of them are produced, the prevalence ofdiseases is threatening their production. The culture
water should thus be stabilized and purified toprevent diseases. It’s been proven that Ceraclean
maintains the chemical quality of the water,
strengthens the shells of shrimps through therelease of minerals (calcium, silicate, and so forth),
improves the survival rate with the biota stabilized
primarily by diatoms, and increases the ADG
through feeding of diatoms, which together increase
the productivity of shrimp culture (Figure 5).

3

It’s being tested at commercial shrimp ponds inThailand to demonstrate its performance andelucidate its mechanism.

Ceraclean is expected to contribute to theconservation of the water ecosystem, providing itwith silicate in a sustainable manner.

As shrimp culture is also expected to becomewidespread in Japan, Ceraclean will be tested foruse in land-based shrimp culture. In addition toshrimps, Ceraclean could be effective for othercrustaceans (crabs, and so forth) and bivalves(clams, and so forth). The role of silicon circulationin the global environment, meanwhile, isincreasingly revealed with the “silica deficiency
hypothesis” advocated7. At the same time, it’s been
pointed out that a decrease in silicate causes red
tides, having detrimental effects on ecosystems.

Ceraclean, for that matter, has the potential ofalleviating the food crisis and changes in the global
environment, going beyond its primary functions.
(“Ceraclean” is a registered brand of Taiheiyo
Cement Corporation.)

Predation
Turbidness

GrowthZoea and Young shrimp

Growth of diatom (stress relief)①Effect ofmineral Supplier

SiO42Ca2+

Enhancement of
exoskeleton②Effect of water
purification[References]

NO3pH Buffer

Mineral elution

Shrimp

Alkalescent

Ceraclean

1.NO
Nationaland Development Agency
2 NH3 ResearchExcrement
Japan Fisheries andResearch
leftover and Education
Agency,Suisan ikushu kankyo senryaku – SuisanMicrobeikushu kenkyu no kongo no susumekata nitsuite -,decomposition
March 2013
2. FAO, The state of world fisheries and aquaculture,
Improve ofsediment
3. FAO Fisheries and Aquaculture(Decrease)Report No. 1053,
Hanoi, Viet Nam, 25–27 June 2013

Microbial
2012,carrier
Rome

Figure 5. Effect of Ceraclean

4. Leaño EM, Mohan CV, Early mortality syndrome
threatens Asia’s shrimp farms, Global Aquaculture
Advocate, 2012, July/August, 38-39[References]

5. Mohammad
Jalil
Zorriehzahra,RezaBanaederakhshan, Early Mortality Syndrome(EMS) as new Emerging Threat in Shrimp
Industry, Advances in Animal and Veterinary
Sciences, March 2015, Volume 3, Special issue 2,Page 64-72

1. National Research and Development Agency
Japan Fisheries Research and Education
Agency,Suisan ikushu kankyo senryaku – Suisan
ikushu kenkyu no kongo no susumekata nitsuite -,March 2013
2. FAO, The state of world fisheries and aquaculture,
2012, Rome
3. FAO Fisheries and Aquaculture Report No. 1053,
Hanoi, Viet Nam, 25–27 June 2013
4. Leaño EM, Mohan CV, Early mortality syndrome
threatens Asia’s shrimp farms, Global Aquaculture
Advocate, 2012, July/August, 38-39

6. Avnimelech Y. (ed.), 1999, Biofloc Technology,
World Aquaculture Society, Baton Rouge, LA
7. National Institute for Environmental Studies Japan,‘Shirika kessonkasetsu’ to kaiikiseitaikei nohenshitsu, Kankyogi NIES Research Booklet,
No394