The impact of a permanent weir (bund) construction on the ecology and fish species diversity of Muriyad wetland is studied. As this wetland area remains 0.5-1 meter below the mean sea level, rice cultivation was carried out by dewatering the fields, after construction of temporary bunds. Permanent weirs were constructed for mitigating the risk of crop loss and to reduce the recurring expenditure for annual bund construction. It was also carried out with a view to increasing the rice production by taking an additional crop during the summer season.  However, these interventions have drastically altered the natural hydrological cycle of the wetland. 

Muriyad wetland also supported a good number of economically important fish species. The present study indicates that the species richness of the fish has come down.  Some of the once abundant species of fishes like the Wallago attu and Heteropneustes fossilis became rare at present. Increased irrigation facilities allowed the farmers to use high yielding varieties of rice. The concomitant use of large quantities of fertilizers and pesticides resulted in the contamination of water. Even though rice production increased significantly from earlier level those developmental activities have diminished several other major functions and vales of this natural wetland.

Address: Department of Zoology, Christ College Irinjalakkuda
Department of Geology Christ College Irinjalakkuda
Phone: 0488-828711  E-mail: kurishinkal@yahoo.com

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