Rajshahi is one of the richest districts of Bangladesh in respect of its vast, divers and unique fisheries resources. There are 9 upazillas in Rajshahi district. Total pond area of Rajshahi district is 7,729 ha which is 2.53% of total pond area of Bangladesh (3,05,025 ha). Where as total fish production of ponds of Rajshahi district is 25,576 MT which is 2.96% of total fish production from ponds (8,66,049 MT) (FRSS, 2009). Now a day due to the degradation of ecological balance, natural resource of fry are destroyed. So, hatchery is the most important source of fry production. There are 18 public hatcheries, 155 private hatcheries and 990 nurseries in Rajshahi division (DoF, 2002). The public hatcheries are well established. The name of the first hatchery of Rajshahi is “Rajshahi Fish Seed Multiplication Farm or Rajshahi Matshow Beej Utpadon Khamar” and established in 1968. This is the only one public hatchery in Rajshahi City Corporation area. Others are established from the year 1989 to 2003. Most of the hatcheries are established in ninetyth decades.
All data are collected over a period of 12 months from September 2005 to August 2006 from the fin fish hatcheries of seven Upazilla of Rajshahi district through survey method with interview.
Essential components of finfish hatcheries of Rajshahi district are described under three categories such as- physical, chemical and biological components.
Physical components:
The land area of hatcheries ranged form 0.4 to 3.9 ha. Hatcheries are providing with different types of circular tanks, houses and bottles. The number and size of these tanks and houses depends on the area of hatchery, ability and choice of hatchery owner. Every hatchery has only one rectangular overhead tank. The volume and water carrying capacity per hatchery ranged form 6.07 to 254.65 cubic metre and 2000 to 90000 gallon respectively.
All hatcheries have the cemented house mainly used for condition of broods and to make hatching hapa (capsize mosquito net). The number of houses raged form 3 to 11. The minimum total volume of houses per hatchery is found as 5.19 cubic metre and maximum as 31.02 cubic metre. It is also observed that houses are not sufficient according to their basic need. The average volume of circular breeding tank is 3.32 cubic metre and the average volume of circular hatching tank is 2.38 cubic metre. The number of bottles ranged form 3 to 13 and the total volume ranged form 1.89 to 12.96 cubic metre. Bottles are widely used in all the hatcheries of Rajshahi district. Details are given in the following table-
Table 1: Physical components of the surveyed hatchery of Rajshahi district
|
Items |
N |
Min. |
Max. |
Mean±Sd |
|
Area of hatchery (dec.) |
24 |
6 |
33 |
418.58±205.56 |
|
Nursery ponds |
|
|
|
|
|
No/ hatchery |
9 |
3 |
9 |
5.22±2.33 |
|
Area (dec) |
9 |
40 |
792 |
186.33±234.85 |
|
Rearing ponds |
|
|
|
|
|
No/ hatchery |
24 |
2 |
8 |
4.13±1.62 |
|
Area (dec) |
24 |
60 |
759 |
337.83±170.73 |
|
Tanks |
|
|
|
|
|
Overhead |
|
|
|
|
|
Volume (m3) |
24 |
6.07 |
254.65 |
48.10±53.51 |
|
Water capacity (gallon) |
24 |
2000.00 |
90000.00 |
16687.50 ±18841.87 |
|
Circular breeding |
|
|
|
|
|
No./ hatchery |
15 |
1 |
5 |
1.80 ±1.32 |
|
Volume (m3) |
15 |
2.48 |
5.04 |
3.32±0.67 |
|
Circular hatching |
|
|
|
|
|
No./ hatchery |
10 |
1 |
2 |
1.20±0.42 |
|
Volume (m3) |
10 |
1.72 |
3.14 |
2.38±0.59 |
|
Bottle |
|
|
|
|
|
No./ hatchery |
24 |
3.00 |
13.00 |
7.92±3.55 |
|
Volume (m3) |
24 |
0.52 |
1.08 |
4.99±2.53 |
|
House |
|
|
|
|
|
No./ hatchery |
24 |
3.00 |
11.00 |
5.88±1.94 |
|
Volume (m3) |
24 |
1.73 |
3.93 |
16.31±6.14 |
Chemical components:
In the Rajshahi district, the private hatchery owners use two types of hormone injection like PG and HCG for induced breeding. First doses (PG) are applied both male and female of native carps at the rate of 0.5 to 4 ml per kg body weight. For Silver carp and Bighead carp, first doses (HCG) are applied both male and female 150 to 1500 IU/kg per body weight. Second doses (PG) are applied only female ranges from 4 to 8 ml per kg body weight. In case of exotic fishes, first dose (PG) are applied both male and female ranged from 1 to 4 ml per kg body weight, second doses (PG) are only used in female ranged from 4 to 11 ml per kg body weight. For cleaning or washing of hatchery equipments, different types of chemicals are used such as Potash, Bleaching powder, Formalin, Copper sulphate, Lime, Methyl blue, Potassium permanganate etc. The duration of washing of tank are ranged from 1 to 2 times per month.
Biological components:
Both native and exotic thirteen fish species are used in hatcheries, among them six are native such as Rui, Catla, Mirgel, Bata, Calbaush, Raikhor, five are exotic carp such as Silver carp, Bighead carp, Carpio, Grass carp, Thaiputi and two are exotic catfish such as African magur and Thai Pangus.
References:
- DoF, 2002. A Brief on Fisheries Resources of Bangladesh (In: Bangla). Department of Fisheries, Dhaka, Bangladesh. p.12.
- FRSS, 2009. Fisheries Statistical Year Book of Bangladesh 2007-2008. Department of Fisheries, Ministry of Fisheries and Livestock, Dhaka, Bangladesh. Volume 25, Number 1. 42pp.
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