János Kepenyes
Fish Culture Research Institute
Szarvas, Hungary
1. BASIC DATA
2. PROCESSING OF BASIC DATA
3. CALCULATION OF WATER REQUIREMENT OF A FISH HATCHERY
4. TEMPERATURE REQUIREMENT OF HATCHING
5. TECHNOLOGICAL DESIGN
6. CONNECTED FACILITIES
In planning of fish hatcheries one has to start from the basic data of reproduction biology, propagation and nursing. Such data can be seen in Tables 1, 2 and 3 for the following fish species:
Common carp |
Cyprinus carpio L. |
Grass carp |
Ctenopharyngodon idella (Val.) |
Silver carp |
Hypophthalmichthys molitrix (Val.) |
Bighead carp |
Aristichthys nobilis (Rich.) |
Tench |
Tinca tinca L. |
Rapfen (Asp) |
Aspius aspius L. |
Pike |
Esox lucius L. |
Pike-perch |
Stizostedion lucioperca L. |
Sheatfish (Wels) |
Silurus glanis L. |
Sterlet |
Acipenser ruthenus L. |
Fish hatchery operations for induced breeding are shown as a function of time in Figure 1, for the propagation of common carp.
The time (in days) is on the horizontal axis. The thick horizontal lines show the occupation of different basins and tanks. Points denoted with small letters refer to different processes and manipulation according to the following:
(a), (e) |
transportation of breeders to the hatchery; in case of common carp this is carried out when the temperature of pond water reaches 18°C; |
(f) |
anaesthetizing of females (e.g. with 1:10 000 solution of MS 222), marking, hormone treatment, first injection (about 8...10 % of the total quantity of pituitary gland); |
(g) |
hormone treatment, second injection (90-92%), the total quantity is 3.5 to 4 mg of pituitary gland/kg of body weight; |
(b) |
hormone treatment of males (2 mg of pituitary gland/kg of body weight); |
(c), (h) |
anaesthetizing, stripping, mixing of sexual products (in dry condition), |
(j) |
adding the fertilizing solution (for activation of sperms and for eliminating the stickiness of eggs), swelling the eggs, tannin treatment (for the elimination of reversible stickiness), swelling, dilution with clear water, placing the eggs into the hatching jars (j); |
(d), (i) |
removal of breeders after coding; |
(k), (l) |
transfer of hatched larvae to the larval rearing tanks; |
(m) |
transportation of the larvae ready to feed. |
The duration of different operational phases (e.g. "j-k" = larval rearing) can be seen in tables of reproduction biology. The durations (a-b) and (e-f) are needed for accustoming the breeders to the ripening temperature (24°C). The period defends on water temperature difference between the ponds and the breeder tanks, in the given case it is 24 hours. Duration of hatching processes (T_{1 }= 9 days) and the intervals between the periods (T = 4 days) can be seen in Figure 1. In case of hatching consisting of several periods the total duration of time can be calculated with the following equation:
T_{n} = T_{1} + T(n - 1) |
(d) |
T_{n} = total duration of hatching, in case of n hatching periods (day)
T_{1} = length of one hatching period (day)
T = time period, e.g. interval between two transportations of larvae (day)
n = number of hatching periods
Figure 1. Hatchery production schedule
In the given case (with common carp) T_{n} = 9 days, T = 4 days; and three periods are represented (n = 3) in Figure 1, thus:
T_{3} = 9+4 (3-1) = 17 days
If we have thirty days for hatching (T_{n} = 30) the number of periods is:
_{}
If we choose n = 6 as a whole number,
T_{6} = 9+4 (6-1) = 29 days, that means 29 days are needed for the hatching.
This method can be prepared for the other fish species as well, by utilization of tables of reproduction biology.
2.2.1 After making the time-plan the next step is the determination of the most important parameters of the hatchery which are as follows:
- Number of larvae produced during one hatching period (T_{1}) and during the total hatching period (T_{n}). These numbers give the capacity of the hatchery;- Number of necessary manipulation devices and tanks, and their volume (breeder tanks', hatching jars, larval rearing tanks);
- Number of necessary brooders; proportion of males and females.
The above mentioned data can be calculated from data of reproduction and fry production (Tables 1 and 2). The method shown in Figure 3 can be applied for this calculation, too.
2.2.2 First one has to determine volume and type of manipulation devices to apply
a) Hatching jarsData given in Table 1 concern the 7 litre hatching jars, shown in Figure 2a. There are some other types in Figure 2. Figure 2b shows a 10 litre hatching jar; Figure 2c shows a 50 litre polyethelene hatching jar for hatching of Chinese carps (grass carp, bighead carp, silver carp). Practical data show that in one 10 litre jar one can place 200 000 eggs of common carp (calculated in dry weight). In the 50 litre polyethelene hatching jar 300 000 eggs of grass carp or silver carp or 250 000 eggs of bighead carp can be placed (also calculated in dry weight).
Table 1 Data on Hatchery Propagation
Table 2 Data on Reproduction Biology of Some Warm Water Fishes
Figure 2. Hatching jars
b) Larval rearing balloon (170 1)
Quantity of hatched larvae put into it
Common carp |
320 000 |
Grass carp |
310 000 |
Silver carp |
310 000 |
Bighead carp |
260 000 |
In our example we use 10 l hatching jars for hatching the common carp, 50 l polyethelene hatching balloons for hatching the Chinese carp (grass carp, bighead carp, silver carp) and 170 l larval rearing tanks for rearing the larvae.c) In the given example tanks of 2 m^{3} useful water volume are used for placing the breeders.
2.2.3 Basic quantities given in paragraph 2.2.1, can be calculated very simply from data of reproduction and nursing by the process shown in Figure 3.
As an example, we can calculate the necessary data for reproduction of common carp.
The characteristic quantities in the figure are written into rectangular fields denoted with "y", e.g. y_{13} is the number of hatching jars (pc), y_{9} is the quantity of stripped dry eggs (million pc = Mpc).
The value "x" drawn on the continuous line between two rectangulars express the relationship between the two quantities, (e.g. x_{9;13} = 0.2 Mpc dry eggs) pc hatching jar. The arrow on the line shows the quantity of "y" unit, which is in the numerator of the related quantity "x".
According to the above, dimensioning is carried out as follows:
a) One draws the rectangulars denoting the quantities "y", and the place of quantities remains empty, only the name and the unit are written in.e.g. "y_{13}............ pc hatching jars"b) Those "y" values for which the tables of reproduction biology give a relationship must be joined. The chosen "x" value must be written beside the joining lines taking care of the direction of the arrow.
e.g. Table 2 shows the quantity of dry eggs which can be stripped from 1 kg of a female in 100 000 ... 200 000 pc. If we choose value 160 000, thenx_{7;9} = 0.16 Mpc/kgc) Those "x" values with which closed loops can be drawn are denoted with broken line. These can be used for controlling the calculation if we know the following regularity. In a closed loop there can be several "x" values with different directions. If the "x" values are taken into account in rotation and where the direction is corresponding with the direction of rotation the "x" value is used as multiplier and where the direction is opposite the "x" value is used as divisor, the result should be 1.
e.g. If x_{9;10} - x_{9;12} - x_{12;14} - x_{14;16} - x_{16;10} gives a closed sling, then_{}
Figure 3. Process of reproduction and nursing of common carp
From it:
x_{10;16} = x_{9;10} . x_{9;12} . x_{12;14} . x_{14;16} = 0.85 .0.85 . 0.94 . 0.96 = 0.65 Mpc/kg
The x_{10;16} is the number of larvae at the age of feeding calculated from 1 kg of dry eggs. Its value is between 0.5 and 0.7 million according to Table 1, and the value calculated from it (0.65 million) is between the two end limits.
d) The next step is the calculation of "y" values that can be represented with the example as follows:The capacity of the hatchery that has to be designed is 30 000 000 larvae, where 30 days are given for the incubation. On the basis of calculation in paragraph 2.1 six successive hatchings (n = 6) can be carried out during the given time. During one hatching the hatchery has to produce
_{}
y_{16} = 5 Mpc feeding larvae
The quantity of hatched larvae:
_{}
The quantity of necessary larval rearing tanks:
_{}
Then we choose 16 pieces, etc.
Necessary size of breeder tanks is 0.56 m^{3} for the males and 1.7 m^{3} for the females. If choosing a 2 m^{3} unit we obviously need 1 pc for the males and 1 pc for the females. If the breeder tanks are of 1 m^{3} size we need one for the males and two for the females.
Further data can be read in Figure 3. As a summary we can say the following: for production of 5 000 000 feeding larvae (y_{16}) 11...12 (y_{4}) females with average body weight of 4.41 kg/fish (x_{3;4}) 5 ....... 6 (y_{5}) males with average body weight of 2.5 kg/fish (x_{5;6}) are necessary. Quantity of stripped dry eggs is 6 510 000 pc (y_{9}) quantity of stripped sperm is 85 ml (y_{n}).
3 pc of 2 m^{3} size or 3 pc of 1 m^{3} size of breeder tanks are necessary for placing the breeders.
Quantity of hatching jars is 32 pc (y_{13}), and that of larval rearing tanks is 16 pc (y_{15}).
Guiding numbers of technological water requirement of hatching are the following:
7 l size hatching jar: see Figure 1
10 l size hatching jar:
for hatching common carp 0.7 ... 2.5 l/min pc jars50 l size hatching jar:
for hatching grass carp, silver carp and bighead carp 0.4 ... 2.5 l/min pc jars170 l size larval rearing tank:
both for larvae of common carp and for larvae of Chinese carps 3 ... 9 l/min pc tanksBreeder tanks: 1 l/min . kg of breeder.
In the hatchery given in the above example the following water requirement is needed:
a) Requirement of waterFor hatching
min. water 0.7 l/min . pc . 32 pc = 22.4 l/min
max. water 2.5 l/min . pc . 32 pc = 80.0 l/minFor larval rearing
min. water 3 l/min . pc . 16 pc = 48.0 l/min
max. water 9 l/min . pc . 16 pc = 96.0 l/minFor breeders
males 14.4 kg . 1 l/min . kg = 14.4 l/min
females 50.9 kg . 1 l/min . kg = 50.9 l/min
total 14.4 + 50.9 = 65.3 l/minThe highest simultaneous water need:
80.0 + 96.0 + 65.3 = 241.3 l/min 15 m /h
b) Requirement of water volume
Water requirement is calculated to the maximum requirement of water for safety reasons. Data concern 5 million larvae.
For hatching
Duration of hatching: |
3.5 d = 84 h |
Water needs: |
8.0 l/min = 4.8 m^{3} . h |
Water requirement: |
84 h . 4.8 m^{3} . h = 403.2 m^{3} |
For larval rearing
Duration of larval rearing: |
3.5 d = 84 h |
Water needs: |
96 l/min = 5.76 m^{3} . h |
Water requirement: |
84 h . 5.76 m^{3} . h = 483.8 m^{3} |
For keeping of breeders
Males | |
Duration in the hatchery |
2.5 d = 60 h |
Water needs: |
50.9 l/min = 3.054 m^{3} . h |
Water requirement: |
72 h . 8.054 m^{3} . h = 219.9 m^{3} |
Total: 403.2 m^{3} + 483.8 m^{3} + 51.9 m^{3} + 219.9 m^{3} = 1 158.8 m^{3} |
As the calculations were made for the maximum water flow, the received number can be rounded to 1 000 m^{3}. Thus, for 1 million 3.5 days-old larvae of common carp one can calculate 200 m of water.
Optimum temperature of hatching can be seen in tables of reproduction biology. It is 20 ... 24°C in case of common carp. If the temperature of water is lower the water must be heated. During a given period of time the necessary quantity of heat for the heating of water is
Q = 1 000 V(i_{2} - i_{1}) + 4 187 . V (q _{2} - q _{1})
where
Q = necessary flow during the period of time (kJ)
V = total quantity of water utilized during the analyzed period of time (m^{3})In the given example: V = 1 000 m^{3} .6=6 000 m^{3}
i_{2} = necessary temperature of water (kJ/kg) used for ripening the breeders
i_{1} = average temperature of available water during the period of time
q _{2} = temperature of water used for ripening the breeders In the given example: 6 = 24°C
q _{1} = average temperature of available water during the period of time say q _{2} = 19°C in the example.
Temperature requirement of the hatchery producing 30 million common carp larvae is
Q = 4 187 . 6 000 . (24-19) = 125 610 000 kJ
for which
_{}
fuel is needed, if the efficiency of boiler is 95% (h _{1} = 0.95) and the main waste is 80% (h _{2} = 0.80).
If the density of the fuel is 0.85 kg/l
_{}
fuel must be used.
Taking into account that the above data are given for production of 30 million larvae with 5°C difference of water temperature, it can be calculated that for production of 1 million larvae with 1°C difference of water temperature, 30 litres of water are needed.
A characteristic flow diagram is shown in Figure 4. Some parts of the installation shown in the flow diagram can be abandoned depending on local situation.
In principle the water source can be of three kinds, as follows:
- surface waters (rivers, lakes, natural beach, artificial beach);- subsurface waters (ground water, deep-seated water, cavern water, spring water, filtered at the riverside water);
- other water sources, secondary utilization (mine waste water, secondary utilization of industrial effluents, cooling water).
Surface waters are for exploitation of a high quantity of water, but they always need purification. Subsurface waters are as clear as drinking water or close to it. Energy requirement of the water intake and costs of constructions of the water intake are specifically higher in case of subsurface waters. In case of a water source containing a large quantity of silt, construction of a separate gravitation settling pond is needed (a), and for intake of subsurface water a separate temperature control pond (b) is needed.
First phase of the water purification is a filtering wall (c) constructed into the settling pond or the temperature control pond. Quantity of water flowing through the unit area of filtering wall is generally 0.15 - 0.20 m^{3}/m^{2} . h.
Sand or gravel can be used as filter media. After getting plugged the filter media can be replaced easily. The water supply of the hatchery can be ensured by gravity or by pumping. Figure 4 shows a water supply by pumping when the capacity of the pumps are calculated from the water requirement. The water needed for backflushing the filters and the social water requirement, have to be taken into account.
If it is necessary, a second filtering unit has to be installed for secondary treatment. This unit usually is a quick sand or gravel filter. The plugged filter media can be backflushed with compressed air and/or high pressure water.
A closed, pressurized quick filter can be seen in Figure 4, that is backflushed with water and compressed air. For the continuous operation two filters are available and only one operates simultaneously while the second is backflushed. The water needed for back-flushing is stored in a separate clear water tank denoted with "f" in the figure. The pumps denoted with "g" ensure the water supply for normal operation and for backflushing. A pressure chamber "h" is used in order to keep the pressure within a certain range. If the temperature of the supplying water is less than required the water has to be heated and its temperature has to be regulated. The heating and temperature control can be ensured with boiler (i), heat exchanger (j) and temperature control valve as is shown in Figure 4.
Oxygen concentration of purified and optimum temperature water generally must be at least 5 g/m^{3}. For this purpose an aeration device (k) must be constructed. If there is no heating, dilution of oxygen can be carried out in the filtering water tank as well (f).
Figure 4. A characteristic flow diagram of hatchery
Breeder tanks can be one of two shapes. The bigger ones (1-10 m^{2} footing area, 1-1.5 m depth) can be constructed of concrete, and coated with plastic material or glazed tile, the smaller tanks (0.5-2 m^{3} volume, 0.6-1.2 m depth) of plastic material or aluminium. The necessary constant water pressure needed for hatching jars (m) and for larval rearing tanks (n) is ensured by an elevated tank (p). The outflowing water from breeder tanks, hatching jars and larval rearing tanks is collected in a drainage pit, from which it is removed by a pump (r). Compressed air for aeration, or rather for backflushing of filters is ensured by a compressor (s) and a pressure tank (t).
For hypophysation and stripping at least one table of 3 × 1 m size is needed. General laboratory benches can be used for this purpose.
Inside the hatchery besides the operational rooms the following compartments are needed:
- store-room
- laboratory
- office social activities (dressing-room, shower, toilet).
Outside the hatchery the following facilities must be situated beside the above-mentioned devices of water intake and water treatment (settling pond, filter-wall) units:
- facilities for keeping the breeders (breeder ponds, wintering ponds);
- technological devices of hatcheries ensure the keeping of larvae only till the beginning of breathing or beginning of food intake.
Further rearing of fry takes place in nursing ponds; the basic calculations are in Table 3.
Table 3 Data of Fry Rearing of Some Warmwater Fishes