e - poz 2 - Central Institute of Brackishwater Aquaculture

was reclaimed up to 1931 (KSSP, 1978). Further, 1320 ha in the Southern part ofVembanad region was reclaimed for agricultural purposes. According to Gopalanet a/. (1983) about 5100 ha. of the backwater has been converted into paddy-cumshrimpculture areas till the 1970s. During 1901 to 1985, an additional area of1500 ha was reclaimed by private ownen for agriculture, cottage industry, andhousrng. The bunding and utlisation of the lake for paddycum-shrimp culture andother activitres is being carried out even now In patches. Thus, out of 36500 ha ofbackwaters which existed till the middle of 19" century, only about 23750ha165.1 %) IS remaining now as open waters. Of this, coconut husk retting activity isesttmated to occupy an area of about 500 ha.Table 1 Rulamltm d Vmtunrd *kr ova th yun- - - - --- - - --- -- --- - -Per~od Area (ha) X 01- Purp~ered&med redmed1981.85 23 91by GCDA and Win TomFlann~ng Trust198145 11 734 11 Hou~lng Kdusbasmnut husk remng0 39 Soulhedy exlasm ofWdrtglon nia?d by GCDA0 07 Foc~hocwtt~an &Mlcpmenl0 03 Cahrn drpyafd CIFT, nwthTanker be& etcBesrdes the hortzontal shrrnkage, The lake also has becn expertcnclng drd5lrrdecltne In 11s depth S~ltatron IS a malor factor contrrbuting to gradudl rhallowrngof the backwater It 1s reported by Gopalan et a1 (1983) that the average depth ofVembanad backwater has been reduced from 6.7 m to 4 4 m between the years1920 and 1980 The sector-wrse depth reduction IS presented In Table-2 Theauthors estlmate that by 1985, the water holdtng capacrty of the lake fromArhrkode to Alappuzha has been reduced to 22 83% of what was rn the begtnnrrrg