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Written by: Swapan Choudhury |
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Indigenous Techniques for Controlling Otter Menace |
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Otter, locally known as ‘udhbiral’/‘bhundar’, is a water- loving musteline mammal belonging to genus Lutra under the family Mustelidae.
The otter is a nocturnal animal. It hunts at night. It is a very vigilant and sly animal. It can swim very fast in water and can remain under water for relatively long durations.
It generally lives in the immediate vicinity of water- bodies and makes a passage through the banks under the root of trees. The passage has several openings and at least one of which opens under the water (Huet, 1986).
Feeding habit
It is a carnivorous animal and chiefly lives on fish (Fig.1) but supplements its diet with other aquatic animals. It eats only the best part of it’s prey and throws away the offal thus causing heavy damage to the fish crop. It does not cause any harm to the seed ponds, only stocking ponds are damaged since it preys upon larger fishes.
Control method
The best means of controlling the otter is by large sized traps. The traps are usually designed considering the general behaviour of the otters. The suitable traps are generally placed in the passages either under water or above water which they commonly follow for catching their prey and leaving the place.
Indigenous techniques
The local farmers generally adopt the following indigenous techniques to catch and control the destructive effects of otter.
Fencing the tank with large meshed gill net pieces
Old pieces of large meshed gill nets are put under water all along the margin of the tank (Fig.2). When the otter enters the tank for hunting its prey it gets gilled in the net and is subsequently caught by the farmers.
Bamboo branches in the tank
Though an otter can remain under water for a long time, yet owing to it’s air-breathing nature, it has to come out of water for breathing. Farmers utilise this characteristic of otter in preventing their crops from being damaged.
Farmers put large number of bamboo bushes/tree branches (without leaves) under water. When the otter goes for hunting in water, it cannot swim very fast due to bushes/branches and meanwhile fish takes shelter in those bushes/branches and escape from the ferocious clutches of the otter (Fig.-3). (This practice is quite common in Bangladesh :Ed).
Attracting through eggs
It is believed that otters like eating hen and duck eggs. Farmers use this as a bait for otter by providing false eggs. Empty egg-shells are filled with strong caustic lime. These false eggs are planted around the tank embankments and under shallow water of the tank margin (Fig-4). When an otter bites into those lime - filled false eggs, it’s mouth gets burnt due to the strong alkaline lime. Once, an otter experiences this, it never returns back to that particular tank for hunting fish.
Providing light on-the water surface of the tank
When light is put above water surface it makes a reflected image under water (Fig.5). Keeping this in mind, the present device has been developed.
At the time of hunting, the otter thinks there is light under water and it does not get into the water and goes back. The farmers save their fish crop from the otter.
Cultivating turmeric on the embankments of the tank
It is realised by the farmers that otter does not like the smell of turmeric. So when turmeric is cultivated on the embankments of the fish tank, generally otter does not come to hunt fish in that tank (fig.6).
It may be suggested that the embankments/ dams and nearby areas of any fish pond always need to be kept free from all kind of terrestrial weeds/undesirable trees (except cultivating turmeric). When the otter is being chased while hunting the fish, it does not get any place above ground to hide.
References:
1. Huet, M. 1986 Textbook of fish culture: Breeding and cultivation of fish. (2nd,ed,), Fishing News Books Ltd, Farnham, Surrey, England, pp.366-367.
2. Choudhury, S. 1993 Sahaj Maach Chas. Fish Farmers Development. Agency, South Tripura district,
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| Volume No. |
Honey Bee, 10(4):5-6,1999 |
