Estimation of potential zones for offshore mariculture in the Indian Sea using geographical information system as a management tool

Coastal mariculture is now facing tremendous pressures, especially from the anthropogenic activities, variable environment, and multi-user conflict. Hence, offshore mariculture is envisioned to enhance the production by promoting the commercial farming (floating cages) of cobia (Rachycentron canadum) and other fin fishes. Essential environmental parameters for mariculture have been selected and converted into thematic layers using Geographical Information System (GIS) tool. Weights of relative importance were assigned to each layer and integrated together through overlay analysis to provide a final model suggesting possible offshore floating marine fish cage deployment sites. In the present study, it is estimated that from 368,009 km(2) area within 100 m depth of Indian Exclusive Economic Zone available for mariculture activities, about 161,188 km(2) area is appropriate for deploying cages. There are 76,396 km(2) of highly suitable and approximately 84,792 km(2) of suitable areas available for mariculture in India including Andaman & Nicobar and Lakshadweep Islands. Analysis of variance (ANOVA-one way) showed significant (p < 0.05) spatial variation for sea surface current, total suspended matter, and chlorophyll-a. This study is an attempt to integrate the weighing criteria and GIS to derive a suitable criterion for deployment of floating cages in the offshore environment, which could serve as a model for similar cases, particularly in the maritime nations for sustainable mariculture.