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The histoanatomical and histonumerical Jessore and Santahar, Bangladesh. Bang. J. Fish.
analysis of the digestive system of Channa Res., 2005, 9(1), 49-50.
punctatus was made. It's digestive tract was
short in length. The digestive system includes BFRI evolved some selected aquaculture
large mouth with sharp teeth, highly distensible technologies viz. polyculture of carps in perennial
oesophagus, a large stomach, a number of ponds, monoculture of short cycled fish species
pyloric caecae and a short intestinal tract. The (BFRI super strain) in seasonal ponds and prawn
mucosal layer of the oesophagus is highly seed production through backyard hatchery system
folded, the stomach was distinct with strong have been demonstrated under Farming System
and branched villi and the intestine was short Research (FSR) component in Jessore and
with long villi. Santahar regions. Both polyculture of carps and
monoculture of short cycled fish species
587 NASER, M.N. & ZAMAN, M. (Dept. of technologies were tested in farmer's ponds in
Zoology, Dhaka University, Dhaka). Relative Kaium Kula village near Jessore town. In
Dependence on the Aerial Respiration of the polyculture trials, seven species comprising of
Indigenous Catfish, Heteropeneustes Fossilis silver carp (Hypophthalmichthys molitrix), catla
(Bloch, 1794). Bang. J. Zool., 2006, 34(2), 229- (Catla catla), rohu (Labeo rohita), grass carp
236. (Ctenopharyngodon idellus), common carp
(Cyprinus carpio), mrigal (Cirrhinus cirrhosus)
The minimum level of dissolved oxygen (DO) and and silver barb (Barbonymus gonionotus) were
other parameters in water required for the normal stocked @ 9,500 (ratio 6:2:4:2:1:5:5); 10,750
life of H. fossilis were measured. Different water (ratio 6:2:4:2:1:5:5) and 12,000 (ratio
parameters in the aquaria showed that the fish died 6:2:4:2:1:5:4) fish/ha respectively in ponds of
from PNR (point of no return) not only for low T 1, T 2 and T 3 having three replications of each.
dissolved oxygen (0.1 mg/1), but also for the The mean highest fish production was 3,148
significant change in important water parameters kg/ha in T 3, followed by 2,899 kg/ha in T 1 and
like ammonia (30.37 mg/1), carbon dioxide (374.8 2,875 kg/ha in T 2. Production of T 3 was
mg/1), water conductivity (85.5 mg/1), and total significantly different (P<0.05) than both T 1 and
hardness (148 mg/1) of water. H. fossilis survived T 2, while there was no significant differences
in an extremely low DO level of water (0.1 mg/l) (P>0.05) between the production of T 1 and T 2.
provided that the concentrations of other factors In case of trial of short cycled fish species, two
like ammonia and carbon dioxide of the water were treatments were tested: T 1 (comprising of BFRI
suitable. The fishes were survived by aerial super strain of Niletilapia, silver carp, common
respiration when the ammonia and carbon dioxide carp and silver barb; ratio 3:5:1:1) and T 2
levels were low. (having only BFRI super strain of Nile tilapia).
Slocking density in both the treatments were
588 PRAMANIK, M.W.A.; RAZZAK, M.A.; same (20,000 fish/ha). In this trial average
HUSSAIN, M.G. & MAZID, M.A. (Bangladesh production was higher in T 1 (2,743 kg/ha) than
Fisheries Research Institute, Mymensingh). that of T 2 (2,369 kg/ha) but the production figure
Demonstration of some selected aquaculture in these two treatments was not significantly
technologies under farming system research in different (P>0.05). Demonstration of backyard
prawn hatchery technology was tested at
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