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Author Bijoy, Nandan S.
Source CUSAT-Thesis
Content type Text
Publisher The University of Waikato, Private Bag 3105, Hamilton, New Zealand
File Format PDF
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Chemistry & allied sciences ♦ Technology
Subject Keyword Coastal wetlands ♦ Backwaters Biodiversity ♦ Chemical and physical parameters ♦ Plankton ♦ Benthos ♦ Fishery ♦ Retting ♦ sustainability ♦ India
Abstract The South West (S.W.) coast of India is blessed with a series of wetland systems popularlyreferred to as backwaters covering a total area of 46128.94 ha. These backwaters areinternationally renowned for their aesthetic and scientific values including being a repositoryfor several species fish and shell fishes. This is more significant in that three wetlands(Vembanad, Sasthamcotta and Ashtamudi) have recently been designated as Ramsar sites ofinternational importance. Thirty major backwaters forming the crux of the coastal wetlandsform an abode for over 200 resident or migratory fish and shellfish species. The fishingactivities in these water bodies provide the livelihood to about 200,000 fishers and also providefull-time employment to over 50,000 fishermen. This paper describes the changes on theenvironmental and biodiversity status of selected wetlands, during 1994-2005 period. The pHwas generally near neutral to alkaline in range. The salinity values indicated mixohalinecondition ranging from 5.20-32.38 ppt. in the 12 wetlands. The productivity values weregenerally low in most of the wetlands during the study, where the gross production variedfrom 0.22 gC/m3/day in Kadinamkulam to 1.10 gC/m3/day in the Kayamkulam. The diversityof plankton and benthos was more during the pre-monsoon compared to the monsoon andpost-monsoon periods in most of the wetlands. The diversity of plankton and benthos wasmore during the pre-monsoon compared to the monsoon and post-monsoon periods in most ofthe wetlands. The average fish yield per ha. varied from 246 kg. in Valapattanam to 2747.3 kg.in Azhikode wetland. Retting of coconut husk in most of the wetlands led to acidic pHconditions with anoxia resulting in the production of high amounts of sulphide, coupled withhigh carbon dioxide values leading to drastic reduction in the incidence and abundance ofplankton, benthic fauna and the fishery resources. The major fish species recorded from theinvestigation were Etroplus suratensis, E. maculatus, Channa marulius, Labeo dussumieri, Puntiussp. Lutianus argentimaculatus, Mystus sp., Tachysurus sp. and Hemiramphus sp. The majority ofthese backwaters are highly stressed, especially during the pre monsoon period when theretting activity is at its peak. The study has clearly reflected that a more restrained and cautiousapproach is needed to manage and preserve the unique backwater ecosystems of South-westIndia
Education Level UG and PG
Learning Resource Type Article