Decision-making framework for identifying best suitable mariculture sites along north east coast of Arabian Sea, India: A preliminary GIS-MCE based modelling approach

Abstract

Mariculture in open seas particularly, sea cage farming is rapidly expanding all along the territorial waters of the Indian sub-continent. Intensification of such new activities in open waters may lead to issues related to sustainability and spatial usage. Additionally, there could be escalation of ecological apprehensions and other cross sectoral conflicts. Thus, in view of the importance of sustainable and judicious utilization of open waters for mariculture development in the country, a preliminary Geographic Information System (GIS) based decision support model and a spatial framework was developed for site selection of cage farms in the territorial waters of Gujarat state, India along the Arabian Sea. The transit trajectory of 20 km sea space accounting to 23949.33 km2 area was modelled under the study. Apart from the preferable biological and oceanographic arrays for the culture system and candidate marine fish species; data on maritime aids, sewage, industrial outlets, river mouths, ecologically sensitive locations and other constraints were marked, re-classified, optimized and benchmarked for the decision-making analysis. The developed comprehensive model consisted office sub-models viz., topographic, physical, chemical and biological oceanographic and socio-infrastructural models. The model explored and demarcated suitable sea space of 12557.74 km2 (52.43% of total) for mariculture. Out of the demarcated area, 27.43% was the most suitable and 25.00% was moderately suitable for mariculture development, emphasizing the untapped potential of the available open waters of Gujarat state. The sensitivity simulation indicated that the developed systematic analytical GIS-Multi Criteria Evaluation (MCE) model was effective, stable and delivered an efficient solution for complex spatial challenges for mariculture site selection process. Further, these results demonstrated that the present spatial decision support model, in particular its methodology and framework, allowed identification of the best suitable sites for mariculture along the territorial waters of the country. The model was adaptable to all maritime states of this subcontinent and could be an effective and useful tool to resolve the complex spatial problems associated with the site selection process for mariculture in open seas. It also provides a way forward for policymakers and stakeholders to formulate strategies for mariculture expansion while governing the marine resources in a holistic, cleaner and sustainable manner.