written by jakir zoology, RU
Ramshagar dighi not an actually sea, but also it’s a big pond known as Ramshagor dhighi. Ramshagar dighi is the largest man made pond (Dighi, Bengali meaning) sited at Tajpur village in Dinajpur. Ramshagar dighi is only 8 km south from Dinajpur Town. It bears some exceptional historical events of national heritage. Ramshagar dighi was excavated by Raja Ram Nath, who dug it in time of the eve of battle of Palashi. Raja Ram Nath begun to dig out the Tank or Dhighi on the basis of ‘Food for Work’ system. About 1.5 millions of labors work in there to excavate the biggest pond of Bangladesh. Ram Nath spends an amount of Taka 30,000 in his time. Most of the historians believe that Ramshagar dighi was created during the 1750 to 1755 AD.
The water area of Ramshagar dighi measures 1039m along north-south and 192.6m along east-west. Approximate depth of the tank is 9.14 and it is surrounded by approximately 10.75 m high wall.
Ramshagar dighi is dense with plenty of fish and wild life animals and also we can see various kinds of migratory birds during the migration season. Bangladesh Parjatan Corporation has taken many steps to beautify this famous sight. Tourists can get pleasure from huge wild life such as Spotted Deer, and other well known animals. For bird seeing, Ramshagar dighi is an ideal place. You can see various kinds of birds like Dove, Myna, and Purple Herons etc. In winter, thousands of migratory birds visit Ramshagar dighi.
Parjatan Corporation Authority who made this place so excellent. In 2001, Ramshagar dighi was declared National park by the authority. After this declaration, importance of Ramshagar dighi has been increasing sharply to the tourists.
v Depth : Maximum depth of ponds is usually recorded during August (10.90 M) and September (10.45 m). Minimum depth of ponds was usually recorded during in February (7.3 m).
Yearly mean of water depth was found as 9.10 ± 1.286.
v Air temperature: It was observed air temperature varied considerably through out the year and range of the monthly average temperature was found to vary from 33.03?C to 10.88?C during the study period. The maximum monthly average air temperature was recorded as 33.03?C in June 2011 and the minimum monthly average air temperature value was recorded as 10.88?C in January 2012.
Yearly mean of maximum air temperature was found as 29.63?C±3.93 and mean of minimum air temperature was found as 20.30?C±6.03. Yearly mean of average air temperature was found as 24.97ºC± 4.92.
v Relative humidity: During the study period highest average humidity 97.37% was recorded in December 2011 and the lowest humidity 55.63 % was February 2012 (Table-3).
Yearly mean of Maximum Relative Humidity was found as 94.73±1.51 and mean of Minimum Relative Humidity was found as 69.42±7.26. Yearly mean of average Relative Humidity was found as 82.075 ±4.14
The rainfall during the study period in Ramshagar showed a distinct seasonal trend in fluctuation. It was recorded maximum as 383.3 mm in August, 2011 and the minimum rain fall was recorded as 1.2 mm in October, 2011and No rain fall during the month of December, 2011 (Table-4). \
The total rainfall over the 11 months was found as 1534.5 mm.
Water temperature variation ranged from 9.9?C to 32.5?C during the sampling period. The water temperature was found to fluctuate from a minimum of 9.9?C at the month of January and maximum of 32.5?C at the month of June (Table-5).
Yearly mean of average water temperature was found as 24.68±4.77.
?H :The ?H value of water ranged from 6.9 to 8.3 during the sampling period. The ?H value of water was found to fluctuate from a minimum of 6.9 at the month of June and maximum of 8.3 at the month of March (Table-6).
During the study period mean of the ?H value of water was found to be 7.67±0.48.
The Dissolved oxygen value of the water ranged from 3.9 mg/l to 5.80 mg/l during the sampling period.
The highest DO was recorded 5.80 mg/l in the month of June and the lowest DO was recorded 3.90 mg/l in the month of August.
During the study period mean of the DO value of water was found to be 4.65 mg/l ±0.62.
Free CO2 value of the water ranged from 0.00 to 2.2 mg/l during the sampling period.
CO2 of the water was found to fluctuate from a minimum of nil in the month of July, August, October, January and February, and maximum of 2.2 mg/l during the month of May and December
During the study period, mean of free Carbon di-oxide value of the water was 0.85 mg/l±0.92.
Different kinds of Phytoplankton were recorded from the study area (Ramsagor) during the 11 months study period. These phytoplankton belonged to Chlorophyceae, Cyanophyceae, Bacillariophyceae, Euglenophyceae, Dinophyceae and Xanthophyceae.
. During the study period total 48 species belonging to the 36 genera phytoplankton were found. (Table-9). The most phytoplankton were found in the month of July and the low amount of phytoplankton were found during the month of March (Table-10).
The green phytoplankton constituted found in large number of phytoplankton. We were found 15 species belonging to 13 genera
The Cyanophyceae constituted were found to be the second dominant group. We were found 10 species belonging to 10 genera of this family. Of these genera,
Bacillariophyceae represents the third dominant group among the algal plankton. We were found 10 species belonging to 6 genera of this type.
The euglenophytes were found little abundance in the study area. We were found 9 species belonging to 3 genera here
The members of Dinophyceae little abundance group. We were found 3 species belonging to 3 genera
The only one member of the group Xanthophyceae (Ophiocytium capitatum) in the Ramshagar dighi.
The most zooplankton were found in the month of June and the less amount of zooplankton were found during the month of March (Table-12). The major groups were Rotifera, Cladocera, Copepoda and Crustacean larvae. A total of 21 genera, including 27 species of zooplankton were recorded
They were the dominant group that they were found 12 species belonging 9 genera during the study period
The Cladocera constituted the second dominant group they were found 7 species belonging 5 genera during the study period
The Copepoda were the third dominant group of zooplankton. 7 species belonging to 6 genera were found during the study period.
Crustacean larvae comprise mainly nauplius larvae.
Correlation between the meteorological, Physico-chemical data
Relationship between the meteorological, physico-chemical data was established. The co-efficient of correlation between different groups of plankton and physico-chemical parameters of water were calculated.
The water temperature showed positive relationship with air temperature (r=0.978), rainfall (r=0.685), Dissolved oxygen (r=0.322), CO2 (r=0.099), phytoplankton (r=0.668), Zooplankton (r=0.338) and negative relationship with Humidity (r=-0.138) and ?H (r=-0.179).
The maximum air temperature showed negative relationship with Humidity (r=-0.152), and positive relationship with rainfall (r=0.686), the minimum temperature showed positive relationship with Humidity (r=0.036) and rainfall (r=0.798), Humidity showed positive relationship with rainfall (r=0.030).
?H showed negative relationship with DO (r=-0.783), CO2 (r=-0.516), maximum air temperature (r=-0.166), minimum air temperature (r=-0.140), humidity (r=-0.303), rainfall (r=-0.064), water temperature (-0.179), phytoplankton (r=-0.126), and zooplankton (r=-0.633).
DO showed positive relationship with maximum air temperature (r=0.315), minimum air temperature (r=0.218), Humidity (r=0.043), water temperature (r=0.322), CO2 (r=0.262), phytoplankton (r=0.143), zooplankton (r=0.514) and negative relationship with rainfall (r=-0.025).
CO2 showed positive relationship with water temperature (r=0.099), maximum air temperature (r=0.006), minimum air temperature (r=0.025), rainfall (r=0.120), DO (r=0.262), zooplankton (r=0.245) and negative relationship with Humidity (r=-0.033) and phytoplankton (r=-0.303).
Phytoplankton showed positive relationship with zooplankton (r=0.391), water temperature (r=0.668), air temperature (r=0.758), humidity (r=0.402), rainfall (r=0.611), DO (r=0.143) and negative relationship with ?H (r=-0.126) and CO2 (r=-0.303).
Zooplankton showed positive relationship with phytoplankton (r=0.391), water temperature (r=0.338), air temperature (r=0.296), humidity (r=0.059), rainfall (r=0.379), DO (r=0.514), CO2 (r=0.245) and negative relationship with ?H (r=-0.633).
Fisheries items prevailing in the study area (Ramshagar dighi)
A total of 45 fisheries species have seen identified from the study dighi. The Piscine fauna including 37 species belonging 26 genera and 12 families under 7 orders (Table-13). The non-fin fisheries species comprised of 8 species belonging to Crustacean (2), Molluscan (6). Among these, 35 are self-recruiting; 6 exotic culturable and 4 native culturable.
Biological Diversity” means the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems, and the ecological complexes of which they are part; it includes diversity within species between species, and of ecosystems. Literal meaning of biodiversity is the diversity of all life forms on earth.
NATIONAL PARKS, WILDLIFE SANCTUARIES AND GAME RESERVES
Protected areas in Bangladesh cover some 2% of the country’s total area or 243 677 ha. There are eight national parks in Bangladesh as well as seven wildlife sanctuaries, five conservation sites and one game reserve.
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather
RESULTS AND OBSERVATIONS
A total of 33 species of wild life and Migratory birds belonging to 24 families and 16 orders were recorded from the study area (Ramshagar dighi). Among these, 1 order, 1 family, and 2 species belonging to Amphibian, 2 orders, 3 families and 4 species belonging to Reptilian, 11orders, 15 families and 21 species belonging to Avian fauna, Among the Avian fauna, 3 orders, 3 families and 7 species belonging to Migratory bird and 2 orders, 5 families and 6 species belonging to mammalian fauna.