Potential Fishing Zones and Bathymetry — How Remote Sensing is used for Indian Fisheries resource management?
Key words: Marine fishing, INCOIS, fishing gears, pelagic fishes, pelagic gears, CPUE, sustainability, WTO, fisheries subsidy agreement
Fishing has been an ancient tradition and a vital source of livelihood for coastal communities. In recent years, India’s fisheries sector has experienced remarkable growth at 10.8% annually, becoming a key contributor to the country’s income, exports, food security and employment generation. The sector aims to increase the fisherfolk’s income through enhancement of sustainable production and productivity, improving the quality and reduction of waste.
While the marine fishing industry in many developed nations has transitioned to large-scale commercial operations, a substantial portion of India’s fisheries sector still relies on artisanal practices. Passed down through generations, these traditional methods form the backbone of livelihoods for a significant coastal population. The art of navigating the seas in search of fishing shoals is deeply ingrained in the culture and sustains economically underprivileged communities along the coast.
However, as the demand for fish continues to rise, industrialization has gradually made its mark in the Indian fisheries landscape. Modern fishing gears and large vessels have transformed the industry, bringing about commercialization and higher productivity. Industrialization of fisheries has also resulted in new challenges. Overfishing, driven by commercial interests, poses a significant threat to the economic, social, and environmental sustainability of the marine ecosystem. As large-scale operations target lucrative fish stocks, the delicate balance of the ocean is disrupted, affecting not only the fish populations but also the communities dependent on them.
Recognizing the importance of sustainable practices, India has taken steps towards aligning its fisheries industry with global goals. The recently concluded agreement on fisheries subsidies at the World Trade Organization (WTO) calls for the elimination of subsidies to fishing vessels engaged in illegal, unreported, and unregulated (IUU) fishing. It also permits subsidies to rebuild overfished stocks to biologically sustainable levels. In this complex landscape, finding a balance between industrialization and the preservation of livelihoods based on traditional practices is crucial. It requires careful management, informed decision-making, and the integration of technological advancements. Efforts are being made to leverage remote sensing and satellite technology to monitor and manage marine resources effectively.
Before going further, Let us try to briefly understand how fishes migrate and how their distribution is affected by taking few examples. The pelagic fishes (being neither close to the ocean bottom nor near the shore) tend to avoid strong ocean currents and surface winds by lodging themselves in the shelter of an underwater relief feature. Another example is of migratory patterns of tuna, mackerel and sardines where they prefer temperate and tropical waters in search of breeding grounds and abundant food sources. The migration patterns can also be due to coastal upwelling (where nutrient rich water can be found towards the western coasts during the monsoon season in India), winter migration (migration of fishes towards southern coasts of India closer to tropical warm waters), vertical migration (exhibited by tuna to regaulate its body temperature while following the vertical movement of its prey).
Modeling marine fish migration involves practical understanding of oceanic and geophysical phenomenons such as weather, ocean currents, sea surface temperature, sea salanity, moon phases, spawning (reproductive) cycles, fish migration patterns, wind speeds, wind directions and many more such parameters. Knowledge of underwater relief features is also a prime advantage in understanding the likely fish distribution in vastness of the ocean. By using remote sensing techniques and satellite imagery over oceans, researchers can identify potential fishing zones and gain insights into underwater bathymetry (ocean depth contours) and fish migration patterns. This information helps fishermen reduce searching time, fuel, and increase their CPUE (catch per unit effort).
Indian National Centre for Ocean Information Services (INCOIS), a government body has taken up the task to provide forecasts on fish congregation in the sea using Remote Sensing (RS) and Geographic Information System (GIS) Techniques. These forecasts are referred to as the Potential Fishing Zones (PFZ) advisories which would indicate the places where possible fish shoals may be present. Features like oceanic fronts, meandering patterns, eddies, rings and up-welling areas indicate the presence of fish. Presence of Chlorophyll and difference in Sea Surface Temperature (SST) are also factors which indicate the fish congregation in the sea. Satellite derived realtime information on the above two factors are used for generating PFZ forecasts. These identified potential fishing zones derived from the satellite images and transferred to navigational charts are provided as PFZ advisories. Being surface parameter based forecast, the PFZ advisories will be particularly useful for pelagic gears like purse seine, gill net and long line and it may also be useful to some extend for mid water trawls and trawlers in the shallow waters. These forecasts are disseminated with an idea to exploit the fishery resources in a sustainable manner and to bridge the gap between estimated and harvested potential.
Progressively governments have used remote sensing technology to monitor and manage the marine resources, keping in check their over exploitation and mitigating habitat degradation. Governments have called for collaborative approach to address the depleting marine resources by launching fish improvement programmes which involve collaborations between various stakeholders, including government agencies, fishery management organizations, non-governmental organizations (NGOs), seafood companies, and local communities. FIPs employ a multi-faceted approach that combines science-based management, policy reforms, and community engagement to drive positive change. Key components of Fish Improvement Programs include:
- Stock Assessment and Monitoring: FIPs involve comprehensive assessments of fish stocks, including population size, growth rates, and reproductive capacity. These assessments help determine the health of the fishery and provide valuable data for making informed management decisions.
- Conservation Measures: FIPs promote the implementation of conservation measures to protect vulnerable species, preserve habitats, and reduce bycatch. This may involve the establishment of marine protected areas, gear modifications, and the adoption of selective fishing practices.
- Traceability and Certification: FIPs emphasize the importance of traceability and certification in ensuring the sustainability and legality of seafood products. Traceability systems enable the tracking of fish from catch to consumer, reducing the risk of illegal, unreported, and unregulated (IUU) fishing.
- Capacity Building: FIPs often include initiatives to enhance the knowledge and skills of fishermen and aquaculture operators. This can involve training programs on sustainable fishing practices, responsible aquaculture techniques, and resource management.
- Collaboration and Partnerships: FIPs bring together diverse stakeholders to work collectively towards common goals. Collaboration between government agencies, NGOs, industry representatives, and local communities is crucial for implementing effective management strategies and achieving long-term sustainability.
- Market Incentives: FIPs leverage market demand for sustainable seafood by encouraging seafood companies to support and promote responsibly sourced products. This can involve partnerships between seafood buyers and producers, providing financial incentives for fishery improvements, and creating market access for certified sustainable products.
By implementing science-based management practices, promoting responsible fishing methods, and engaging stakeholders at various levels, FIPs aim to ensure the long-term viability and sustainability of fish stocks, protect marine ecosystems, and support the livelihoods of fishing communities.
In this part we have taken a brief overiew of the Indian marine fisheries landscape, tried to understand how pfz advisories are used in maximizing marine catch sustainably and how remote sensing is helpful in managing marine resources. Stay tuned for the next part..
