A beel thicky infested with water hyacinth

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I) Ox-bow lakes : These are cut of portion of river meanders. The basins are relatively narrow, long, deep and have either bmt or straight shapes. They derive the name from their shape, which is usually horse-shoe shaped, cmcent shaped or serpentine. They receive wata from the parent river through the old channel or neighbouring catchment areas . 11) Lake-like wetland: These are wide and shallow with irregular contours. They may be connected to the river through channels or receive wata from it during floods. During the mown season, the entire neighboring area gets flooded. turning the beel into a vast sheet of water whenas during non-monsoon seasons the water spread area shrinks to the basin proper. rlr) True tectonic dcpress~ons : 'These are created by tectonic act~vit~es l~ke canhquakes and usually resemble natural lakes with regular contours. Normally. they are not connected to riven through connecting channels but may recelve water from the latter during floods. Such tectonic wetlands are common in thc northeastern region (e. g. Chanddubi beel in Assarn) 119 Meteorite lake: These are created by the impact of fall of a meteorite on earth. Such heels have regular, nearly oval shape and abnormally high banks on all sides, which, according to geologists, can be created when the left over portion of a large meteorite h~ts the earth. The morphometric features of the brcls are similar to those of volcanic lakes. except for the fact that they are located in the plains and are very shallow. Clussiljcurton based on woler rerenrrvm I) Seasonal beels: These are shallow floodplain wetlands, which periodically pet inundated by monsoon rains and floods but completely dry up during summer months. ir) Perennial beels: Deeper and permanent beels, which retain water round the year.
Clossrjicafion based on depth i) Shallow beels: Beels having maximum depth up to 5 metres. il) Medium deep beels : Bcels. which have maximum water in the range of 5 to 10 metres. I~I) Deep beels : Beels having maximum depth of over 10 metres I) Small beels : Efl'ect~ve area less than 100 hectares i ~ ) Medium beels : Effective area I00 to 500 hectares 11i) Largc heel . Effective area more than 500 hectares Ox-bou shaped. crescenr shaped. serpentine, oval, irregular braided channels. ctc In\estlyat~ons on floodplain wetlands of West Rengal carrted out hq ClFKl for the Idst decade and A half tndlcate that water res~dence and renewal ttme as well as the extent of nlacrophvtc lntestation are the two most Imponant factors affecting thew ecology and fisheries In beels that retarn rlvenne connecttons, the continuous water exchange affects the nutnent ~npur-output ratlo While this adversely affects the btologteal productlv~ty of the ecosystem, rt helps rn delaytng eutrophtcatlon process Raptd water rtmewal also helps In breaktng the thermal stratrficalton. rf any, In deep heel. whtch IS benelicral for nutrlent recycling and gaseous exchange At the same tlme. continuous Hater flow does not allow the plankton speclcs to stahtltze. resulting in lower plankton dens~ty and pnmary productton rates tn such heels S~m~larly, aquattc macrophytes use up large chunks of plant nutrients, thus maklng them unava~lahle for the growth of phytoplankton (Phytoplankton IS a better prlmary producer than macrophytes tn heels for efficient conversion of energy) The aquallc weeds also render
Page 1: ECOLOGY AND FISHERIES OF BEELS IN A
Page 4 and 5: Ecology and fisheries of beels in A
Page 6 and 7: Project participants V-V, Sugunan 8
Page 9 and 10: INTRODUCTION lndia has extensive fl
Page 12 and 13: Importance of beels If managed alon
Page 14 and 15: 6) The standing water (Ientic compo
Page 18 and 19: operatton of fishing gear difficult
Page 20 and 21: Tabk 4. DhMbuUon of bcclr la tbe ri
Page 22: Table S ronfd. ... . .... /an& M~tr
Page 25 and 26: floodplains an flooded. Lakelike be
Page 27 and 28: heavily infested with aquatic veget
Page 29: Table 6. contd. . . ... pH &g.C Av.
Page 33 and 34: Watcr Quality In floodplain wetland
Page 35 and 36: Temp. Trmrp. PH DO CQ, TA Hudnear S
Page 37 and 38: TDS ahride SiO, CI Mg Fc PO, NO, Dl
Page 39 and 40: Table 8. contd. TDS Chloride SiO, C
Page 41 and 42: Biotic communities The abundance an
Page 43: Dbhlct Tabk 10 Planktom In differen
Page 46 and 47: l rabh 10, conki eorc.rr.os T ~ W D
Page 48 and 49: Tnhle 10 cod Morlgaoa Mon Kamrup Dm
Page 50: oligochactea and insccto. Thc bee18
Page 53 and 54: However, Samrajan north in the dist
Page 55 and 56: A beel thicky infested with water h
Page 57 and 58: Fish yield potential Fish yield pot
Page 59 and 60: FISH AND FISHERIES Fish fauna Many
Page 61 and 62: Barpeta Area Deptb Dominant fbb (ha
Page 63 and 64: view of recmitmcnUautostocking in t
Page 65 and 66: I1 Fishing operations in beel
Page 67 and 68:
1. Liming in split dosea It regular
Page 69 and 70:
whole operation is baaed on captive
Page 71 and 72:
Community metabolism Community meta
Page 73 and 74:
Fig. 5. Path- of enorgy flow Jn (Or
Page 75 and 76:
stocLtagmtc~egmwthrmteof~speckrsttt
Page 77 and 78:
Proper stocking and harvesting sckd
Page 79 and 80:
Ferrlisarion / Borrom raking Since
Page 81 and 82:
Flg. 8. Dlrgnmmatlc npnwnbSion of c
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A beel thicky infested with water hyacinth

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