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Aquaponics for Conservation of Wetland Ecology, Aquatic Biodiversity

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Since the wetlands face increasing threats from pollution, habitat loss, and climate change, aquaponics presents a viable strategy to support wetland conservation and promote aquatic biodiversity… It can help in reducing pressure on natural wetlands and minimized habitat encroachment. It can provide alternative livelihoods and lessen dependence on wetland resources like fishing, hunting, and vegetation harvesting, thereby reducing overexploitation

 

Maibam Birla Singh and Rameshori Yumnam

Wetlands are among the most productive ecosystems on Earth, providing critical ecosystem services such as water filtration, flood regulation, carbon sequestration, and habitat for diverse species. They support aquatic biodiversity by serving as breeding, feeding, and nesting grounds for a variety of fish, amphibians, birds, and invertebrates. Additionally, wetlands contribute to climate resilience by absorbing and storing excess water during extreme weather events, reducing the impact of floods and droughts.

This year’s World Wetland Day theme “Protecting Wetlands for Our Common Future” emphasizes the need for protecting wetland for the future. The communities and the inhabitants surrounding wetlands are intricately dependent on these water bodies for their sustenance and livelihoods.

Wetlands provide essential resources like water, fish, and vegetation, supporting local fisheries, agriculture, and livestock rearing. Communities rely on these ecosystems for food, income, and cultural practices, while wetlands also serve as natural buffers against floods and droughts, ensuring water security.

The dependence of both aquatic and terrestrial organisms on wetlands forms a complex web of interactions, where any disturbance to the ecosystem from anthropogenic activities such as pollution, habitat degradation, or climate change, can have cascading effects on biodiversity and human well-being. It can also threaten wetland health and aquatic biodiversity. This interdependence highlights the need for conservation efforts towards maintaining ecological balance and management to sustain the health and productivity of these vital ecosystems.

To overcome the challenges involved towards wetland protection, various nature-based sustainable solutions for conservation of wetland ecology and aquatic biodiversity are suggested. At present, ‘Aquaponics’ is recognized as one of nature-based climate resilient sustainable food production system.

Aquaponics is a modern scientific adaptation of the ancient technique of food production used in natural lakes or other water bodies to produce food. It may be noted that the use of fish waste as fertilizer for crops was practiced since the ancient times.

In China, rice-cum-fish culture was practiced around 2000 years ago. It was practiced in Hanzhong and Mian Countries in Shanxi Province and in Emei country in Sichuan Province.

The fish stocked in the rice fields are common carp (Cyprinus carpio), crussian carp (Carassius auratus), and grass carp (Hypophthalmicthys molitrix). The most well-known examples of integrated farming are the “stationary islands” in shallow lakes in Aztecs, Mexico, estimated 1150–1350 BC.

An agriculture method called ‘Chinampa’ was practiced (illustrated picture of Chinampas’s farming from Chinampas in ancient Mexico, picture: http://incredibleaquagarden.co.uk/media/chinampa1.gif), where plants were raised on floating gardens and waste materials dredged from water channels or canals, and the surrounding areas were used to irrigate and grow the plants. Similar cultures around Inle Lake in Myanmar, Waru Waru agriculture of the Uru people along the shores of Lake Titicaca in Peru, Dal Lake in Kashmir, and Loktak Lake (Phumdi) in Manipur are also examples of integrated framing in water bodies.

The working principle of modern aquaponics is based on the concept of re-circulating aquaculture system (RAS) and the use of nutrient-rich aquacultural waste water as source of nitrogenous compounds for growing plants in a hydroponic culture unit, which in the process depurates the water that is returned to the aquaculture tanks, and, thereby, reducing the environmental impacts. It simply combines the advantages of RAS and hydroponic system while overcoming the individual stand-alone drawbacks.

The system results in a symbiosis between fish, microorganisms, and plants, and encourages sustainable use of water and nutrients, including their recycling. Within this synergistic interaction, the respective ecological weakness of aquaculture and hydroponics are converted into strengths. This substantially minimizes the need for input of mineral fertilizers and output of waste, unlike when run as separate systems.

Aquaponics system integrates aquaculture (fish farming) with hydroponics (soil-less plant cultivation) similar to a natural ecosystem mimicking natural wetland processes, enhancing water conservation, nutrient recycling, and ecological balance. Since the wetlands face increasing threats from pollution, habitat loss, and climate change, aquaponics presents a viable strategy to support wetland conservation and promote aquatic biodiversity.

Leveraging on the natural symbiosis between aquatic organisms and plants, aquaponics provides ecological benefits such as water purification, habitat restoration, and sustainable resource management. In terrestrial aquaponics system, by producing food in controlled environments, aquaponics reduces the need for converting wetlands into agricultural or aquacultural lands, preserving critical habitats for aquatic and terrestrial species.

Aquaponics can help in reducing pressure on natural wetlands and minimized habitat encroachment. It can provide alternative livelihoods and lessen dependence on wetland resources like fishing, hunting, and vegetation harvesting, thereby reducing overexploitation. Further, in aquaponics the aquaculture waste water is used for growing plants thereby controlling pollution and enhancing water quality through nutrient recycling.

In traditional agriculture and aquaculture, nutrient runoff from fertilizers and fish waste often pollutes adjacent wetlands, leading to eutrophication. Aquaponics recycles nutrients in a closed-loop system, reuses waste water preventing runoff and maintaining water quality. Further, unlike conventional farming, aquaponics reduces water uses by more than 90% and avoids the use of synthetic fertilizers, pesticides, ensuring that the surrounding wetlands remain free from harmful chemical contaminants, thereby reducing the chemical inputs and produce chemical free food.

In open water-bodies, integrated wetland aquaponics systems that replicate natural wetland functions and supports biodiversity can be introduced to restore degraded wetlands, and thus create a rehabilitating ecosystem services through improved water filtration and nutrient cycling, by using natural wetland vegetation and processes.

Since aquaponics utilizes aquatic plants as biofilters to remove excess nutrients and contaminants, it can improve water quality and reduce pollution impact without the need of additional cost. Wetland aquaponics system designed within wetlands can utilize artificial floating rafts or natural floating vegetation like phumdi for plant cultivation, combining food production with wetland restoration and management.

Designing aquaponic environments that provide refuge and breeding grounds for native fish and invertebrates can also provide habitat enhancement for aquatic species. By producing fish in aquaponics systems, pressure on wild threatened fish populations may be reduced, helping to prevent overfishing and allowing ecosystems to recover.

Aquaponics systems can be designed to cultivate native fish species like Bangana devi (Ngaton, Khabak) and Osteobrama belangeri (Pengba), preserving genetic diversity and reducing the risk of invasive species disrupting local ecosystems. Some aquaponics systems like the re-circulatory constructed wetland aquaponics system can simulate natural wetland habitats through habitat mimicry, offering refuge and breeding grounds for aquatic organisms, especially in areas where wetlands are degraded.

Apart from vegetables, by growing edible wetland plants such as water spinach (Ipomea Aquatica, Kolemni in Manipuri), taro (Colocasia esculenta, Yendem in Manipuri), Chinese taro (Alocasia cuculata, Sinju paan in Manipuri), water mimosa (Neptunia prostrate, Ekaithabi in Manipuri), water dropwort (Oenanthe linearis, Komprek in Manipuri) etc., can enhance food security apart from increasing habitat complexity and supporting diverse aquatic life.

The wetland plants in aquaponics systems absorb and store carbon dioxide, mitigating greenhouse gas emissions and increase carbon sequestration. Further, the constructed wetland systems can contribute to flood control by absorbing excess water and gradually releasing it, maintaining hydrological stability. Thus, aquaponics can provide nature-based solutions for the conservation of wetlands and associated aquatic biodiversity with increase climate resilience.

In conclusion, aquaponics offer sustainable pathways to balance food production with the conservation of wetland ecosystems and aquatic biodiversity. By reducing human pressure on wetlands, mitigating pollution, and restoring degraded areas, aquaponics not only ensures the health of these critical ecosystems but also contributes to global conservation and sustainability goals. Scaling up aquaponics, combined with education and supportive policies, can ensure that wetlands and their biodiversity are preserved for future generations. The authors are optimistic that aquaponics can be a practical solution in sustainable management of wetland resources.

(The authors are currently monitoring the Freshwater Ichythyology and Sustainable Aquaculture Laboratory (FISA-Lab) at the University of Manipur)

 

 

 

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