4. Conditioning of ZWD system

There are several steps in conditioning of ZWD system; they are (1) microbial maturation in culture animal tanks; (2) acclimatization and stocking of shrimp or prawn; (3) feeding management; and (4) microbial manipulation that will be described in detail below.

#### 4.1. Microbial maturation in rearing tank

Rearing tank conditioning was started by adding limestone (CaCO3) and gravel at the bottom of the tank as substrate for nitrifying bacteria and then fill with disinfected seawater or freshwater (depends on cultured animal habitat). Afterward, 2% v/v of nitrifying bacteria consisted of AOB, and nitrite NOB at 10<sup>6</sup> CFU/mL is inoculated in the tank. 0.3 gr NH4Cl (approx. 1 ppm of NH<sup>þ</sup> <sup>4</sup> ) is added per tank as ammonium source. After NH<sup>þ</sup> <sup>4</sup> and NO� 2 concentration was about 0 ppm, NO� <sup>3</sup> concentration was rising. It shows that AOB and NOB activities to convert ammonium to nitrate works. About 2% v/v of microalgae, i.e., C. calcitrans at 10<sup>6</sup> cell/mL and 0.05% v/v of heterotrophic bacteria, i.e., B. megaterium at 10<sup>7</sup> CFU/mL are inoculated into each tank. After the water turns to brownish color, the tank was ready to be used.

#### 4.2. Acclimatization and stocking shrimp and prawn

After microbial maturation, we entered to the next steps or we can acclimatize shrimp or prawn in the same time with tank maturation. White shrimp PL-10 was acclimatized at room temperature (25 � 1�C), while prawn was acclimatized from PL-40. Afterward, white shrimp was usually stocked at intensive farming using stocking density of 400 ind/m3 and prawn at stock 60 ind/m2 . White shrimp and prawn were usually conducted for 90 and 60 days culture period, respectively.

#### 4.3. Feeding management

Feed management was done by creating an estimation of daily feed (blind feeding; Table 2). The amount of feed was determined according to the mean body weight, estimated survival rate, and feeding rate, where:

$$\text{Daily Feed } (gr) = \text{SD} \times \text{ABW} \times \text{FR} \times \text{SR} \tag{1}$$

Total consumption of feed and shrimp condition can be monitored via ancho based on the remaining amount of feed in the ancho. Feeding frequency was four times a day, given at 09:00,

Table 3. Strategy to measure feeding efficiency following common feeding procedures created by Shrimp Club Indonesia

Ancho Uneaten feed Results Decision

A 0 0 0 0 4/4 Add more 5–10% B 0 0 0 + 3/4 Sufficient C 0 0 + + 2/4 Subtracted 5% D 0 + + + 1/4 Subtracted 10–15% E + + + + 0/4 Subtracted 20–30%

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This stage explores the characteristic of ZWD system that is similar to green water technique. Microbial components consisted of nitrifying bacteria, microalgae, and heterotrophic bacteria are added into the system every 2 weeks. The additional of microbial components is to maintain water quality and to balance microbial cycles in the system. In addition, microbial components are also given into the tank, if the ammonium concentration significantly rises. Similar to maturation step, nitrifying bacteria, microalgae, and heterotrophic bacteria were

Monitoring is to evaluate the performance of ZWD system. Some parameters in the ZWD system that must be monitored are water quality and the growth performance of shrimp or prawn.

Maintaining water quality is important in aquaculture system because water is habitat of aquatic animal so it should be monitored periodically. Factors that affect water quality are temperature, dissolved oxygen, pH, and inorganic nitrogen concentrations. Water quality parameters are divided into two groups: psychochemical and microbiological parameters.

The optimum range of water temperature allows aquatic organisms to perform metabolism and growth. Temperature is an important water quality parameter, because it can affect the

also added in the same volume to maintain the system performance.

12:00, 16:00, and 21:00 [13].

in Lampung [personal communication].

4.4. Microbial manipulation

5. Monitoring ZWD system

5.1. Water quality parameter

5.1.1. Psychochemical parameters

5.1.1.1. Temperature

With: SD is the stocking density (Ind/tank), ABW is the average weight of shrimp (gr), SR is survival (%), and FR is feeding rate.

The feed was placed on the feed tray (ancho) and then checked to gain daily information of feeding accuracy (Table 3).


Table 2. Blind feeding in super intensive white shrimp cultivation at 25 � 1�C.


Table 3. Strategy to measure feeding efficiency following common feeding procedures created by Shrimp Club Indonesia in Lampung [personal communication].

Total consumption of feed and shrimp condition can be monitored via ancho based on the remaining amount of feed in the ancho. Feeding frequency was four times a day, given at 09:00, 12:00, 16:00, and 21:00 [13].

#### 4.4. Microbial manipulation

4.1. Microbial maturation in rearing tank

concentration was about 0 ppm, NO�

4.2. Acclimatization and stocking shrimp and prawn

(approx. 1 ppm of NH<sup>þ</sup>

308 Biological Resources of Water

was ready to be used.

stock 60 ind/m2

period, respectively.

4.3. Feeding management

rate, and feeding rate, where:

feeding accuracy (Table 3).

survival (%), and FR is feeding rate.

Rearing tank conditioning was started by adding limestone (CaCO3) and gravel at the bottom of the tank as substrate for nitrifying bacteria and then fill with disinfected seawater or freshwater (depends on cultured animal habitat). Afterward, 2% v/v of nitrifying bacteria consisted of AOB, and nitrite NOB at 10<sup>6</sup> CFU/mL is inoculated in the tank. 0.3 gr NH4Cl

activities to convert ammonium to nitrate works. About 2% v/v of microalgae, i.e., C. calcitrans at 10<sup>6</sup> cell/mL and 0.05% v/v of heterotrophic bacteria, i.e., B. megaterium at 10<sup>7</sup> CFU/mL are inoculated into each tank. After the water turns to brownish color, the tank

After microbial maturation, we entered to the next steps or we can acclimatize shrimp or prawn in the same time with tank maturation. White shrimp PL-10 was acclimatized at room temperature (25 � 1�C), while prawn was acclimatized from PL-40. Afterward, white shrimp was usually stocked at intensive farming using stocking density of 400 ind/m3 and prawn at

Feed management was done by creating an estimation of daily feed (blind feeding; Table 2). The amount of feed was determined according to the mean body weight, estimated survival

With: SD is the stocking density (Ind/tank), ABW is the average weight of shrimp (gr), SR is

The feed was placed on the feed tray (ancho) and then checked to gain daily information of

Average body weight (gr) Feeding rate (%) Survival rate (%) Feeding tray monitoring intervals (h)

<1 10.0 100 3.5 –3 8.0 98 3.5 –5 6.0 96 2.5 –7 5.0 94 2 –9 4.0 92 2

Table 2. Blind feeding in super intensive white shrimp cultivation at 25 � 1�C.

<sup>4</sup> ) is added per tank as ammonium source. After NH<sup>þ</sup>

. White shrimp and prawn were usually conducted for 90 and 60 days culture

Daily Feed gr ð Þ¼ SD � ABW � FR � SR (1)

<sup>3</sup> concentration was rising. It shows that AOB and NOB

<sup>4</sup> and NO�

2

This stage explores the characteristic of ZWD system that is similar to green water technique. Microbial components consisted of nitrifying bacteria, microalgae, and heterotrophic bacteria are added into the system every 2 weeks. The additional of microbial components is to maintain water quality and to balance microbial cycles in the system. In addition, microbial components are also given into the tank, if the ammonium concentration significantly rises. Similar to maturation step, nitrifying bacteria, microalgae, and heterotrophic bacteria were also added in the same volume to maintain the system performance.
