Assessment of impact of aquaculture on mangrove environments in the South East Coast of India using remote sensing and geographical information system (GIS).

Abstract

Rapid development of aquaculture in coastal areas has raised worldwide concern on its potential role in mangrove habitat loss. This study is an attempt to assess the impact of shrimp aquaculture on the mangroves eco systems. The land resources used for aquaculture development were mapped from satellite data and analysed using Geographical Information System (GIS) to assess the extent of conversion from different land types to aquaculture. The digital data from Landsat -TM of 1987, IRS 1B - LISS II of 1994, IRS 1C- LISS III of 1998 and IRS - 1D LISS III of 2004 were used for the study. Aquaculture area has increased from 6.91 ha in 1987 to 386.33 ha in 2004. Change detection analysis using GIS indicated that mangroves of 4.84 ha and degraded mangroves of 6.16 ha were converted for aquaculture. Major development of aquaculture has occurred from agricul tural lands (176.99 ha) and fallow lands (234.25 ha). Forest plantation of 21.68 ha, mud flats of 23.63 ha, water bodies of 18.13 ha and sandy areas of 60.87 ha were converted for aquaculture between 1987 and 2004. The aquaculture farms of 15.03 ha, converted from agricultural lands were reconverted back to agriculture due to disease problems. The shrimp culture practiced in 109.47 ha was abandoned and lying as fallow lands. Man groves at Pichavaram were not affected due to the development of shrimp culture. The study indicated that remote sensing and GIS techniques are ideally suited to the task of assessing changes in the mangrove environments due to aquaculture and have the potential to contribute for sustainable aquaculture.