Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Predatory Behaviour of a Snakehead Fish (channa Striatus Bloch)

M. Das
Department of Aquaculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh

R. K. Basak
Department of Aquaculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh

F. Ahmed
Department of Aquaculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh

S.C. Chakraborty
Department of Fisheries Technology, BAU, Mymensingh 2202, Bangladesh

Abstract/ Executive Summary:

The predatory behavior of a snake-head, Channa striatus (Bloch) on Labeo rohita fingerlings was studied in the laboratory. The study was conducted with six C. striatus (120 to 21 0 g and 22 to 28 cm) over 24h a day for 3 weeks. Three different sizes prey of large (2.00g and 5.8cm), medium (1.30g and 4.5cm) and small (0.72g and 3.5cm) were used for the first week and then medium size prey for 2^nd and 3rd weeks. All the predators preferred eating the small group of L. rohita although all three size groups of L. rohita offered were available: It was found that the prey fishes remained together aside of the aquarium from the predator. Predator first targeted a prey, drove fast towards it, the prey tried to escape from the predator's attack using a specific route and finally the predator grasped the prey on head first and then engulfed. The handling time ranged between 45 and 50 sec. The time of peak feeding was found in the morning and in the evening of day. When 2 or 3 predators were kept in one aquarium, they engaged in fighting, head on, followed by an attack on the mouth region by the dominant one, and subsequently on the pectoral fin and caudal fin of the defeating one. After 2-3 days they became habituated to remain together and did not involve themselves in fighting.

Keywords: Channa striatus, Labeo rohita, Predator

Location: BAU

Start Date: 00-08-1995

End Date: 00-08-1995

Program Area: Animal Health and Management

Commodity: Fish

Objectives:

To study the predatory behavior of C. striatus over 24h period of the day to provide a basis for future management programme of Indian carp culture, by offering the fingerlings of Labeo rohita as prey animal with following objectives of determining the preference of the prey size by the predator, studying the diet feeding pattern of the predator and the feeding behavior of the predator.

Methodology:

Materials and methods - The present study was conducted in the laboratory of the Department of Fisheries Technology, Bangladesh Agricultural University, Mymensingh, for 21 days in the month of August, 1995. Six glass aquaria (120cm x 60cm x 45cm) marked as aquarium No. 1, 2, 3, 4, 5 and 6, were used to conduct the experiment. The aquaria placed in a row on a table were filled with clean tap water up to the level of 40cm. Aerator (Daivo 8400) were used for aeration in the aquarium water over 24h. Experimental fish and acclimatization - The disease free predatory fish, C. striatus caught by cast net from a beel (large natural depression filled with water), were collected from a fish trader. The healthy prey fingerlings of L. rohita commonly called rui, were collected from Bangladesh Fisheries Research institute, Mymensingh. The collected predators were placed immediately into a stocking-tank in the laboratory and the saturated dissolved oxygen level in water was maintained by continuous aeration. Predators were then treated with salt (2% dip for 1 hour) and. malachite-green (1 ppm) as a prophylactic treatment. The predators were kept in the stocking-tank for seven days and one prey for each predator was given as food into the tank on the first day and the number of prey in the tank were gradually increased upto the satiation of predators for the next 6 days. On the other hand, the collected prey ( L. rohita) were· transferred into the laboratory and placed into another large stocking-tank. They were also given prophylactic treatment. Water in this tank was aerated by an aerator continuously. They were kept into the tank without supplying any food for first two days. After that supplementary food at the rate of maintenance ration (about 1% body weight) was supplied to the fingerlings. Behavior of predator - To observe the predatory behavior six C. striatus (22-28 em and 120-210 g) were selected and numbered as P1, P 2, P 3, P 4, P 5, P 6 and each fish was released into the aquarium bearing corresponding number. Each of the aquarium was provided with one predator for first 7 days; then two predators in each aquarium for another 7 days and three predators in each aquarium for the last 7 days. Prey were grouped into three as large, medium and small having mean length, weight and body depth of 5.8cm, 2.0g, 0.98cm; 4.5cm, 1.3g, 0.84cm and 3.5cm, 0.72g and 0.71 cm respectively. Thirty prey (1 0 from each size-class) were offered 11as sufficient11 to each aquarium for the first week and the medium size prey of 60 were offered to the predators in each aquarium for the next two weeks. Continuous aeration in each aquarium was maintained for dissolved oxygen. The temperature of the water ranged between 28° and 30°C. Fecal matters from the aquarium was cleaned regularly by the method of siphoning in the morning and the water inside the aquarium was then replaced (about 1/3) with fresh clean aerated tap water without disturbing the fish. Predatory behavior was observed for 24h regularly during the study period. The time and method of prey-capture were observed and recorded. At the start of the experiment total length (cm), body weight (g), jaw length (cm) and mouth gape (cm) of predators were measured and recorded. Data, on prey eaten by predators were recorded quantitatively and qualitatively. Movement pattern of the predator as well as that of the prey were observed by naked eyes over 24h period during the experiment.

Source of Information: Bangladesh J. Fish. Res., 2 (2): 127-137, 1998

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

All the predators preferred eating the small group of L. rohita although all three size groups of L. rohita offered were available: It was found that the prey fishes remained together aside of the aquarium from the predator. Predator first targeted a prey, drove fast towards it, the prey tried to escape from the predator's attack using a specific route and finally the predator grasped the prey on head first and then engulfed. The handling time ranged between 45 and 50 sec. The time of peak feeding was found in the morning and in the evening of day. When 2 or 3 predators were kept in one aquarium, they engaged in fighting, head on, followed by an attack on the mouth region by the dominant one, and subsequently on the pectoral fin and caudal fin of the defeating one. After 2-3 days they became habituated to remain together and did not involve themselves in fighting.

Knowledge Management: Journal