Chalan beel is the largest and important wetland in the north west region of Bangladesh. The area of this beel is 375 sq. km. at during flood period from July to November and 52-78 sq. km. at dry winter and summer. The average depth of more than 2 m during dry season and more than 4 m at rainy season.
It is located between 24.35 to 24.700 north latitude and 89.10 to 89.350 east longitudes. It covers an area belonging to Singra, Grudashpur and Boraigram upazila of Natore district, Chatmohar upazila of Pabna district, Tarash, Roygonj and Ullapara upazila of Sirajgonj district and Ahasanganj and Manda Upazila of Noagaon district.
Rivers and their tributaries are formed a water network over the entire chalan beel area. The rivers are Atrai, Gur, Korotoa, Boral, Mara Boral, Tulsi, Chenchma, Bhadai, Chikni, Bogomja, Khubjipur, Telkupi and their innumerable tributaries, interconnecting canals and channels.
The average rainfall is 1775 mm, atmospheric temperature is 8-40.90 c. Water temperature is recorded as 11.5-310 c, water transparency 18-55 cm, pH 7.2-8.5, Dissolve O2 5.1-9.6 mg/l, Free CO2 1.3-12.3 mg/l, Carbonate alkalinity 8.3-15 mg/l, Bicarbonate alkalinity 82-117 mg/l.
The identified species of fish is 129, annelids 8, arthropods 11, mollusces 13, amphibians 7, reptiles 17, birds 34, mammals 8 and aquatic vascular plants 52. The number of cultivable fish specie is 7 and self recruited fish species more than 50.
There are 7 main types of nets, 10-14 types of traps, 5-7 types of line, 5-7 types of wondering gears found.
The following parameters are recorded during visit in this beel at Singra area at 2002:
Air temperature 34.420c and humidity 78. Water temperature 26.44-28.520c with an average depth of 30 cm to 100 cm. Water depth 203-290 cm, transparency 51.2 cm, colour grey-greenish, source flood and rain, water duration near about 5-6 months.
The common zooplankton are Daphnia, Cyclops, Moina, Notholca, Keratell and Asplanchna; phytoplankton are Spirogyra, Volvox, Nostoc, Microcystis; aquatic vascular plants are Topa pana (Pistia stratioles), Kachuri pana (Eichhornia crassipes), Keshordam (Jussiacea repens), Kalmilata (Ipomoea aquatica), Malancha (Enhydra flucktuans), Arail (Leorsia hexandra), Shapla (Nymphaea nouchali). 20 species of terrestrial tree are available.
16 species of fin fish are very common, 14 species of small indigenes species of fish are dried by sun drying method. Mainly 4 types of fishing net are available here such as Drag net, Frame net, Gill net especially current jal (monophyletic gill net) and khepla jal. Traditional traps, gears and craft are very common and available. Large mechanized boat is usually used for transporting goods as well as traveler.
The following parameters are observed during visit in beel at Singra area at 2003:
Air temperature 29.66-32.380c. Water temperature 28.55-29.630c with an average depth of 30 cam to 100 cm. transparency 13.92-15.5 cm, colour grey-greenish, source flood and rain, water duration near about 5-6 months. Dissolve O2 4.47 mg/l, Free CO2 3 mg/l, Bicarbonate (HCO3) 31 mg/l.
The following parameters are observed during visit in beel at Grudaspur and Taras area at 2005:
Air temperature 320c. Water temperature 310c with an average depth of 30 cm to 100 cm. Water depth 203-290 cm, transparency 20 cm, colour turbid by silt, source flood and rain, water duration near about 5-6 months.
Dissolved Oxygen 4.35 mg/l, Free CO2 12 mg/l, pH 7.25, Hardness 38.5
Hossain M. A.1 2005 Fisheries resource development of Chalan beel. Key note speech of a National Seminar. Organized by North West Fisheries Resource Development and Management Project (Third Phase), Parbatipur, Dinajpur, Department of Fisheries, Bangladesh.
1 Professor of Zoology and Former Vice chancellor, university of Rajshahi, Rajshahi-6205, Bangladesh.
All Honours students of 1st, 2nd and 4th batch of the Department of Fisheries, University Rajshahi-6205, Bangladesh who help to prepare this page by giving photographs and information