Dr. S.N.Biswas* and Sri D.Basu**
To meet the increasing demand of fish food with the increasing population, possibly one of the ways might be higher growth rate of fish in the aquaculture. Many avenues have been tried in aquaculture but none have so far been observed that much effective.
In this study the effect of ultrasonic sound on the growth of fry to fingerling have been studied for the first time and found to have been highly significant in enhancing fish growth rate by 35%.
Key word:Fish growth; ultrasonic sound.
In the aquaculture practice measures are adopted so that fish remain on move, in order to keep the fishes healthy with an ultimate objective for higher growth rate and subsequent enhanced yield.
Towards this, scare netting and other different methodologies/ techniques are practiced by the farms viz. release a few nos highly carnivorous fish Boal (wallago attu), chital (Notopterus chitala) and usual practice of regular netting (drag netting). The same principle has been applied in this study as to create ultrasonic sound in the water body to keep the fish active (on move).
M/S Telenet (an electronic company working on the innovation and development of electronic equipments for fish growth), at 12, Pollock street, Kolkata-700001 approached to us, with one of their product namely ‘Fish Chaser’claimed to emit ultrasonic sound which keeps the fish active (running) and results rapid growth and ultimately gives 22 – 30% additional yield.
It looks like a cylinder, lower end conical (sound emitting zone) having dimension of 3” diameter X 17” long plastic body and is operated by 3 volt ‘D’ type dry cell (2 pieces).
Effective area for one such Fish Chaser is 1000 sq. meter of water body having 1-meter depth and battery life is 1 month.
In this study farm pond (P – 4) was selected having a water area of 0.12 ha (1200 sq. meter) and average depth 4’. The pond was prepared as per the schedule for nursery management and 6 lakhs IMC spawn (@ 5000000/ ha), produced at our FFRS hatchery, was released on 25.6.04.
On 01.7.04 the fry size measured was 0.5 cm (average) on this day i.e.; at the age of 6 days two nos ‘Tele Chaser’ was installed in the pond with the help of one each of bamboo stick (Fish Chaser was tied with the bamboo stick, fixed in the pond bottom in such a manner so that the conical end of the Chaser faces pond bottom and the other end remains just submerged). Before this 2 new dry cells were installed in each Chaser and it was made on (in operation). The Chaser was installed in the middle line of the pond water area keeping a distance of 4’ from the pond embankment.
Normal husbandry for nursery management was practiced i.e.; application of feed, netting (1/4” mesh size net on 7th to 10th day, Chatjal on 14th to 15th day etc.). And in such operation growth and health of the fry were recorded. The result may be seen in Table – 1.
Simultaneously one control was also maintained where this Fish Chaser was not installed, all other husbandry operation remain same.
The duration of this trial was 65 days.
Tele Net Fish Chaser before it is installed in the pond.
Tele net Fish Chaser being installed in the fish pond for studying growth of fish fry.
Table – 1: Growth record of fish in the pond with Fish Chaser & without Fish Chaser.
Fig-1: Diagram of Telenet Fish Chaser.
Diagram of Tele net Fish Chaser
In a time period of about one and half months the length, individual fry weight and survivality were found to be in the Experimental pond 7.2 cm, 3.2 gm and 65% respectively which in the control pond were 4.2 cm, 0.93 gm and 60% respectively.
On comparing the result obtained in this experiment it is revealed that applying similar package of practice, productivity in the experimental pond (with Telenet – Fish Chaser) is 35 times higher than the control pond.
The result shows that the Fish Chaser definitely have a positive impact on the fish growth; it enhances fish growth rate and survivality that lead to higher yield and production of healthy fish seed.
This study shows the way to work further on this line and to study the effect on the table fish production.
Dr. S. N. Biswas,
Dy. Director of Fisheries
(Fresh Water Aquaculture & Research)
Freshwater Fisheries Research Station
Kulia (Kalyani): P.O. N.S.Sanatorium: Nadia
Sri D. Basu
Asstt. Research Officer
Freshwater Fisheries Research Station
P.O. N.S.Sanatorium: Nadia