Mapping of potential sea-cage farming sites through spatial modelling: Preliminary operative suggestions to aid sustainable mariculture expansion in India

Sea cage farming in marine open waters is considered as the most viable technique in Indian mariculture to enhance production. Owing to the support of the government in research and development, and policy initiatives, marine cage farming is progressing steadily in the country. Technological guidance from research institutions and financing under the ambitious “Pradhan Mantri Matsya Sampada Yojana (PMMSY)” and blue growth mission objectives have inspired stakeholders and fisheries administrators in maritime states to explore open sea cage culture. Site selection is a key parameter affecting the success of cage culture systems and, technically analysed geo-referenced demarcation of spatial information is necessary for minimising the risks. Thus, in the light of rising demand for spatial allocation of coastal areas, the present study identifies and aggregates locations within 3 km of the coastline, that have the potential for sea cage farming operations in the country. The site suitability was examined based on optimal standards required for the prospective candidate species selected for mariculture in India. The locations were vectorised in a GIS platform, and the potential areas available for sea cage installations were demarcated. An optimised site suitability schema was developed for the spatial demarcation of potential site selection.The preliminary results identified 134 sites covering a total area of 46,823.2 ha suitable for marine cage culture along Indian territorial waters. Among the coastal states, the top three states holding the maximum area suitable for sea cage farming are Andhra Pradesh (11,792 ha), Gujarat (11,572.2 ha) and Tamil Nadu (7,673 ha). It is envisaged that spatial suitability demarcation even on this pilot scale will accelerate the expansion of sea cage farming in the country

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

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

Novel decision-support system for augmenting sustainable lobster production through comparison of mariculture systems at increasing stages of technological development

In the face of depleting wild stocks of lobster globally, mariculture is widely viewed as a technology for enhancing production, resource efficiency, economics, and effective management of dwindling stocks while supporting livelihood security. We used a novel multi-stage experimental strategy followed by robust non-linear growth model simulations for establishing a Decision-Support System (DSS) to foster sustainable and cleaner production practices in lobster mariculture. The strategies explored in the first stage, which dealt with rearing lobsters in sea cages at increasing levels of technological development, significantly enhanced lobster production and thus, culture system productivity 5.9 times over unsustainable conventional systems. Growth performance, feed utilization, and survivability of lobsters were found to be significantly ameliorated in culture setup-3 (P ≤ 0.01), which was the most technologically advanced setup. In the second stage, non-linear models were fit to growth curves, and the best-fit models were used for the prediction of lobster biological metrics in the mariculture systems. These predictions were then validated using in-situ allometric traits. The DSS thus developed can effectively aid decision-making to optimize culture duration, stock condition, feed optimization, and harvest size to maximise economic returns from lobster mariculture while ensuring sustainability

Energy efficiency and economics of small-scale fisheries (SSF) in India: A VIKOR based multicriteria decision-making model for sustainable fisheries management

The present study addresses the crucial sustainability concerns in small-scale fisheries (SSF) against the backdrop of escalating anthropogenic activities and climate change impacts on marine fishery and ecosystems. Our study focused on a traditional fishery exploitation area spanning 12,646.12 km2 along the Southwestern Coast of Kerala, India, and explored four widely used fishing gears. We established an integrated decision-making VIKOR framework, and preferential modelling by incorporating techno-economic and environmental aspects to draw the optimal solutions. Leveraging 10 sustainability indicators, the boat seine emerged as the most sustainable gear, showcasing significant profitability (US$ 16,126/year−1 net profit) and remarkable energy efficiency, surpassing gillnetters, longliners, and shore seiners by 8.4, 4.9, and 3.0 times, respectively. The Fuel Use Intensity (FUI) and CO2 emissions analysis (F value = 58.37, P < 0.0001) emphasizes the ecological implications. The developed VIKOR sustainability index, introduced in this study, effectively assesses gear efficiency and sustainability. Further, the study revealed that gear selectivity, technical specifications, and operational trajectories considerably influence the index dynamics. This research aligns with the global commitment to the Voluntary Guidelines for Securing Sustainable Small-Scale Fisheries (SSF Guidelines) and contributes scientifically to Sustainable Development Goals (SDGs). By bridging empirical rigor with international frameworks, the study could aid in sustainable fisheries management and environmental stewardship, deemed essential for the global pursuit of ecological, economic, and social sustainability in small-scale fisheries

Thermal tolerance and environment adaptability of Indian pompano: Discovery of a resilient candidate species for sustainable mariculture production in a climate change scenario

Mariculture, a relatively low-carbon aquaculture sub-sector than other protein producing livestock systems is an important food-producing industry, continues to significantly expand its production at the global scale. Nevertheless, the sector's growth is vulnerable to climate change, typically driven by the temperature in the existing environment. The long-term sustained growth is contingent on the effective mitigations and adaptation to predicted temperature change and its consequences on production. In such perturbations, one of the adaptive strategies is finding a new potential candidate marine fish and documenting its thermal tolerance for adapting it as a climate-resilient species in mariculture systems. Furthermore, understanding the upper and lower thermal tolerance limits of species is of compelling necessity in the process of recommending species' suitability to diversify the mariculture sector other than their natural niche. In this context, an investigation into the thermal adaptability of Indian pompano, Trachinotus mookalee, was tested at six different acclimation temperatures (Tacc), which revealed that the CTmax of the species ranged from 37.02 °C to 43.22 °C and CTmin from 12.66 °C to 19.22 °C. The study derived the Acclimation Response Ratio (ARR) of this species for the first time, and the response was found to be resilient demonstrating the species' adaptability to varying thermal conditions. in the tested temperature range. Hence, we concluded that the species could be a promising candidate for tropical biomes for mariculture development in context of climate change. This could assist the sector to opt for an adaptation (species becoming adjusted to specific conditions) and mitigation strategy against predicted climate change impacts, especially in those regions where climate extremes prevent conventional species farming practices. Also, this study points out the need and pressing priority for estimating the thermal tolerance of cultured aquatic organisms so as to assess their potential to integrate with the projected climate change scenarios in sustainable production systems