Cite this article as:

Raghuvanshi,  M.S.,  Patil, N.G., Daripa, A., Naitam, R.K.,   Kharbikar, H.L., Malav  L.C., and Pandey L. (2021) Seaweeds as future resource of livelihood options in India. Food and Scientific Reports. 2 (8) 26-30.

ABSTRACT

Seaweeds are renewable marine resources of coastal ecosystems, offering invaluable benefits to the human kinds. It is getting growing attention of the Government of India through its Pradhan Mantri Matsya Sampada Yojna (PMMSY) scheme for enhancing the income of seaweeds farmers. These marine plants are a wonderful source of seafood, fodder, feed, manure/ fertilizers, medicines, antioxidants. Various challenges have posed threat and unprecedented pressures on seaweeds, resulting in extinction of certain demanded species.  Intensive efforts, policy planning and broad strategies are under way towards prioritizing the seaweed cultivation and value chain addition in the support to coastal regions of the country. Scientific and policy interventions in seaweed cultivation are required to focus on its potential to improve human livelihood.

Keywords: Seaweeds, red algae, brown algae, green algae, ecosystem services

"Seaweeds" are the species of marine plants and multicellular algae with red, green and brown, growing in the sea, rivers, lakes, and other water bodies. Bluegreen algae (Cyanobacteria) has also been are also well-thought-out as seaweeds (Sims and Zandee, 1981 and James et al., 2006) that are non-flowering photosynthetic macrophytes, occupies about 71% world-wide and these natural renewable resources form the food for herbivores (Rao, et al, 2018). In world, about 20000 marine plant species have been reported (May 1988). Seaweed ecological growth depends on two environmental factors i.e. sea water and light (Kilinc et al, 2013). Seaweeds are an integral part of coastal ecosystems and offer invaluable ecosystem services supporting the life of many marine forms (Ganesan et al., 2019). These are the large, more visible plants and major resource of Indian Ocean, growing on coral, rocks and other submerged strata in the shallow tidal zones of the sea, providing home and food for sea animals. Seaweeds fulfils their nutrient requirements from sea water directly as they lack the complex rooting system. Twenty eight per cent of the Earth’s oxygen comes from rainforests and rest is produced by marine plants in the atmosphere and forms the basis for all ocean life (Martinez, 2019). Few are very tiny phytoplanktons that are found suspended in the sea water and these also provide marine food chains. Whereas kelps are large seaweeds, forms the root structures, helps attaching to hard surfaces. Kelp is rich brown seaweed which contains vitamins A, B6, B12, C, E, K, folate, thiamin, riboflavin, niacin, pantothenic acid, iodine, calcium, magnesium, iron, sodium, phosphorus, and very small quantity of zinc, copper, manganese, and selenium (Kennedy, 2020).   

 Status for seaweeds in India and abroad

There are 20000 species of marine plants world-wide (May, 1988) amongst which seaweeds are major and an excellent source of phycocolloids such as agar, alginate and carrageenan and food, fodder, feed and liquid seaweed fertilizers. Only 221 seaweeds are utilized commercially worldwide (Rao et al., 2018).  The total resources of brown and red algal by fresh weight are around 1721x10 tonnes (Michanek, 1975). The world production of commercial seaweeds has grown by 119 per cent since 1984 (Rao et al., 2018). China holds first rank in seaweed production followed by North Korea, South Korea, Japan, Philippines, Chile, Norway, Indonesia and USA (FAO, 2013). Oza & Zaidi, 2001 and Thivy, 1960 stated that the commercial production of agar and alginate was initiated around 1966. In Indian coastal states are the main hubs and Mumbai, Ratnagiri, Goa, Karwar, Pulicot and Chilka are supposed to be the better places for rich seaweed diversity. One third coastal population mainly depend on marine resources in India (Ganesan et al., 2019). Comprehensive survey made by Central Salt and Marine Chemicals Research Institute revealed the standing stock of seaweeds to the tune of 97400, 7500 and 19345 tonnes (wet weight basis) from the coasts of Tamil Nadu, Andhra Pradesh and Lakshadweep islands, respectively (Kaliaperumal and Kalimuthu, 1997). In India, it has risen to 26000 tonnes during 2010-18 and it is 15 per cent of the world seaweed farming mainly green and red species (Ranjan, 2021). Seaweed diversity of 434, 194, and 216 species of red, brown, and green seaweeds, respectively have also been reported on secondary data basis (Oza and Zaidi, 2001). 

In 2018, global production of seaweeds was to the tune of 32.4 million tonnes for both wild- and cultivated aquatic algae, where farmed seaweeds represented 97.1% by volume. The world production being 32386.2 thousand tonnes on wet weight basis (100%) and Asia produces 32226.3 thousand tonnes i.e. 99.51 per cent of total production of seaweeds. It has more than tripled, up from 10.6 million tonnes in 2000 to 32.4 million tonnes in 2018. India produced 5300 tonnes (wet weight basis) in 2018 i.e. 0.02 per cent (5.3 thousand tonnes) of the global production. In India, the total production of cultured and wild seaweeds is 5000 tonnes and 25000 tonnes, respectively in 2018 with a market value of Rs. 300-500 crores (Ranjan, 2021).

 Common Types of Ocean Plants

There are four groups, colours such as blue-green algae (phylum: Cyanophyta, up to 1500 species), red algae (phylum: Rhodophyta, about 6000 species), brown algae (phylum: Ochrophyta, classes: Phaeophyceae, about 1750 species) and green algae (phylum: Chlorophyta, classes: Bryopsidophyceae, Chlorophyceae, Dasycladophyceae, Prasinophyceae, and Ulvophyceae, about 1200 species), and the seaweeds are a polyphyletic group (Kilinc et al., 2013). Ocean has two categories of plants i.e. one is floating freely on the surface and second are often noted on shallow waters near the oceanfront. Kelps are the largest marine water plant growing maximum up to 250 feet long along the coastlines. While red algae grows in warm tropical waters and are also rich in protein and vitamins. Coralline algae have very fine filaments, hard as the rocks growing to support the coral reef structures. Seagrass is a shallow water rooted plant on/ near coastlines. It is also a popular food source for crabs and lobsters throughout the temperate marsh waters where it commonly grows. Sargassum is known as gulfweed or sea holly (brownish-green coloration, dense, bushy fronds, and berry-like gas-filled bladders), playing an important role at initial stages of many marine species.

Seaweeds and kelp are types of algae as marine vegetables and are incredibly nutrition rich in vitamin A, calcium, iron, zinc, and iodine. More amount of iodine consumption sometimes might negatively affect thyroid if consumed in excess. Seaweed covers red, brown, and green varieties of algae, growing in lakes, rivers, and oceans (Cohan, 2018). While kelp (also a type of seaweed and Kombu is the Japanese translation) develops only in saltwater environs, harvested near rocky ocean coastlines. It does not float (due to a root-like system called a holdfast) but stays in a single spot with continuous movement of water to get its nutrients. It stays in a single spot that anchors it to the ocean floor and allows groups of kelp to grow together. It is a primary ingredient in dashi, the broth used in many Japanese dishes.

 Table1. Wild collection of Algae in India during 1978-79 to 2002-03

Red algae

Gelidiella   acerosa, Gracilaria edulis,

G.  crassa, 

G.   folifera and 

G.   verrucosa 

Hypnea   musciformis

240 to
  1518 tons dry for agarproduction 

Brown
  algae

Sargassum

and Turbinaria

651 to
  5534 tons dry for alginate and LSF production

(Kaliaperumal et al., 2004)

In Indian agriculture, importance of seaweeds products such as bio-fertilizer and bio-stimulants is immense and that might lessen the chemical fertilizers for improving the soil fertility. There are enough opportunities to promote existing indigenous seaweed-based technology (they are Sargassum spp. Kappaphycusalvarezii and Gracilaria spp.) instead of importing. (Ganesan et al., 2019).                 Buck (2019) revealed that seaweeds decomposes after harvesting into 60% methane and 40% carbon dioxide which can generally be utilized as a biofuel stored to keep it from the atmosphere, respectively. Ocean with more seaweed if afforested could sequester 53 billion tons of CO2 annually as compared to normal annual emissions of about 40 billion tons.

 New seaweeds discovered

Marine biologists from Central University of Punjab have discovered two new native species of marine algae namely Hypneaindica from Kanyakumari in Tamil Nadu, and SomnathPathan and Sivrajpur in Gujarat and Hypneabullata from Kanyakumari and Diu island of Daman and Diu. The commercial value of Hypnea variant seaweeds have been reported to fetch good monetary value if commercially cultivated since it contains Carrageenan, a biomolecule commonly used in the food industry. Secondly it can be utilized as fertilizers if fed to livestock with seaweed for low methane emission, combat beach erosion and one of the ingredient in preparation of toothpaste, cosmetics and paints (Kamal, 2021).

Uses

Seaweeds are a wonderful sea-food, fodder, feed, manure, medicines and antioxidants for crops besides as phytochemicals (agar, agarose, alginate and carrageenan) and were treated as delectable food between 600 to 800 BC. In India, these are consumed as sea-vegetables and salads (Caulerpa, Eucheuma and GacilaIria species) in many dishes. Seaweeds are richest source of proteins, lipids, carbohydrates, minerals, vitamins (A, B, C and st Niacin) and antioxidants as valuable food supplements of present century (Kilinc et al., 2013, Subba Rao et al., 2007). It can be integrated with food and renewable energy parks for recued cumulative footprints. Kilinc et al., (2013) stated that edible seaweeds viz. Himanthaliae longata (sea spaghetti), Bifurcaria bifurcata, Laminaria saccharina (sweet Kombu), Mastocarpus stellatus and Gigartina pistillata are rich in moisture, ash (24.9–36.4%),, protein (10.9 to 25.7%), lipids (0.3–0.9% and oil content, and fibre.

 Table 2: Utilization of seaweeds

 Forget (2019) revealed that edible seaweeds can create stable blood vessels in the body and for wound dressings. Brown seaweeds is harvested globally, is further utilized to create the Alginate product. This is very important medically, utilized as food, dental impression and for safer dermatological use (Watson, 2019).

Potential of seaweeds and Governmental schemes

Prime Minitser Sh Modi said that scientific interventions anmd technologies hold the key to improve the productivity in Indian agriculture. Coastal seaweeds have great potential for human health care and agriculture. Former President Dr Kalam said that seaweed cultivation yields fertilizer utilizaed in land-based crops. IFFCO has brought organic bio-stimulant product range out of seaweeds SAGARIKA- a seaweeds fertilizer granules which was also districbuted to the farmers of adopted village by ICAR-NBSS&LUP, Nagpur. Pradhan Mantri Matsya Sampada Yojana reveals lot of opportunities to enhance the production and income of seaweed farmers. Seaweed based biostimulants accounts for 25% of Indian biostimulants, rest 75% of the seaweeds based biostimulants rare imported from  North America and Europe and based on cold water marine algae species. Institutes involved in thes ector are CSMCRI, CMFRI and NCSCM which are soon starting pilots for clearing the pathways for its cultivation and roadmaps. India has Kappaphycus, Euchema cottonii and Gracilaria and may import Euchema Spinosium to acclimatise, study and release to the farmers. In roadpams, several points have been proposed to develop seaweed site map and pilot studies. Deep sea seaweed cultivation infrastructures have been proposed to create to encourage farmers. It has been proposed to encourage and support adoption of seaweed based nutrient in dairy, poultry and fish diets to improve immunity, reduce mortality and increase productivity. It is a far more profitable product as comapred to fishing. On the other hand, it is labour intensive process and generate employment with a Rs 500-700 per day basis (Ranjan, 2021). 

Ecosystem services provided by Seeweeds

Ecosystem services provided by seaweeds are enormous. They act as excellent nutrient scrubbers (especially dissolved nitrogen, phosphorus and carbon). The most positive part of seaweed cultivation is serving for habitat restoration and comes under the aquaculture component where it provides oxygen, while the other animal and microbial components consume oxygen, in terms of sequestering carbon dioxide and slowing down the global warming. It plays an active role in reducing coastal acidification. The Integrated Multi-Trophic Aquaculture (IMTA) diversification approach (fish, seaweeds and invertebrates) could be an economic risk mitigation and management option.

Limitations and strength in Seeweed Cultivation

Climate change is effeting the livelihood of farmers in India particularly the small and marginal farmers (Tamta et al., 2020). There are many limitations of seaweed cultivation the important ones are: automation in seaweed farming, transfer of proven technology, poor research and developments, policy guidelines, and climate change. More over aquatic ecosystem is challenged due to heavy exposure of chemicals (Bordoloi, 2021).  

 Conclusion

Seaweeds are a large and diverse group of simple, typically autotrophic organisms ranging from unicellular to multicellular forms. They are useful as basic utilities, industrial uses and ecosystem in the development of new functional ingredients. These are presently excellent sources as nutrients; animal feed supplements biofuel, and biofertilizers and growth stimulants. The Government of India also launched a scheme i.e. Pradhan Mantri Matsya Sampada Yojana aimed at enhancing production and income of seaweed farmers.

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