Small Indigenous Fish (SIF): Status and Contributions in Nutrition and Livelihood Security of India: A Review

According to the Food and Agriculture Organisation (FAO) of the United Nations (1997) fish is a vital source of food for people. It is important single source of high-quality protein, providing ~16% of the animal protein consumed by the world’s population, fish constitute the major source of dietary protein after cereals and milk for human beings and are the sole source of animal protein for majority of the people. The Small Indigenous fish species are those which attain a length of about of 25 cm or 6 inches at maturity (Felts et al., 1996) and rich source of nutrients. Kongsback et al., 2008 studied the consumption of nutrient rich freshwater small indigenous fish by human beings and stated that SIFs provides better nutrition since generally eaten as whole including head, bone and eyes and thus all available nutrients including the micronutrients get utilized. These fishes are important equally well known for rich source of proteins, fatty acids, vitamins and minerals. It has been reported that some species such as mola (Amblypharyngodon mola), dhela (Osteobrama cotio cotio), darkina (Esomus danricus) and kaski (Corica soborna) contain high amount of vitamin A and other micronutrients and minerals (Thilsted et al., 1997). It is reported that vitamins and minerals available in one kg of SIFs are equal to those available in approx fifty kilograms of big fishes, such as Indian Major Carps (Mohanty 2010). In Bangladesh, it is reported that the small fish is the only source of vitamin A and calcium as dietary source for rural masses (Roos et al., 2003). SIFs play important role in preventing malnutrition due to protein deficiency and more specifically the micronutrient deficiency thereby safe guarding both nutritional as well as livelihood security of the rural population (Mohanty et al., 2013). It is well opined that the availability of self-recruiting species (SRS) in both natural and managed habitats is important for livelihood of the rural poor (Roos et al., 1999; Mazumdar and Lorenzen 1999). Extensive carp culture along with small indigenous species is certainly a source of additional income and dietary protein to the rural families, incurring no additional cost besides being environment friendly (Bayen et al., 2020). The role of SIF in providing micronutrients is very critical especially where micronutrient deficiency is a big problem (Zafari and Ahmed 1981). The aim of this review mainly focuses on the important nutritional component available in fish. Therefore, diversification of aquaculture with high valued small fish species of regional importance holds great promises in Indian economy.

To review the paper, Google Scholar search engine was the primary source to collect literature and perform sequential online searches for traditional knowledge and similar identified sections. A systematic evaluation of all the papers, reports and books on the related subject was done to document the information. The available data was categorised under different heads and presented accordingly.

Availability of different species of SIFs
 
India is endowed with a total of about 2,246 species of finfish, out of which 765 are freshwater fish recorded from inland water bodies like wetlands, ponds, rivers, ditches and paddy fields (Lakra et al., 2010). Out of recorded 765 freshwater fish species, about 450 were small Indigenous fishes (SIFs), having maximum length of 30 cms. Felts et al., 1996 enlisted 45 fish species as SIFs including 18 species of carps and minnows, 9 species catfishes, 9 species perches and others in Bangladesh. Further they sub-categorized SIS into three main groups based on the maximum length of the fish up to 7.5 cm, 15 cm and 25 cm. These species do not get any score in national statistics that are largely based on catches reported from major landing centres in high quantity and these fishes tend to be sold and consumed locally (Halwart 2008; Roos, 2007a). The high demand SIF species are identified by Sarkar and Lakra 2010.
 
Capture and culture resources
 
These fish species inhabit widely diverse natural ecosystems ranging from rivers, tributaries, streams, flood plains, wet lands, lakes, low lying paddy fields, swamps and seasonally inundated low lying areas. Maximum diversity of SIFS has been recorded from North East Region of India followed by Western Ghats and Central India. Fish-cum-paddy culture is also well known from these water rich areas. Suresh et al., 2007 studied the biology of a SIF (A. mola) from a floodplain wetland of West Bengal, India and reported as a good source of income generation for the community.  Small sized fishes are usually considered as obnoxious weed fishes and these are subject to eradication from the culture system. Kumari et al., 2021 studied the food selectivity and reproductive biology of small indigenous fish Indian river shad, Gudusia chapra in a large tropical reservoir of India and observed a new trend of reproductive pattern. The qualitative estimation of the stomach contents revealed herbi-omnivorous feeding behavior of these fish species. The absolute fecundity of the individuals ranged from 749 to 15044 and ova diameter ranged from 0.10-2.00 mm. The gonadal indices (GSI, MGSI and DI) indicated that spawning extended throughout the year with peak reproductive activity in October, March-April and July (mean absolute fecundity ranged from 4000 to 6000).
 
Loss of SIFs
 
Freshwater aquatic environments are experiencing serious threats to both biodiversity and ecosystem stability and many strategies and priorities have been proposed to solve this crisis. The major threats to the SIF’s are as: loss of natural habitats, use of small mesh sized gears, dewatering, use of insecticides and pesticides, industrial and domestic pollution, siltation of water bodies, invasion of exotics and disease. Under several schemes announced by the Government for fisheries enhancement programme and culture based fisheries had intensified by regular stocking of water bodies with Indian Major Carps (IMC). In this process, small native fish species are being affected and their population is declining fast. Small fishes are known as weed fish in aquaculture management practices. These are mostly eradicated using rotenone and other pesticides.  Therefore, a drastic shift in the species composition and diversity is marked in favour of major carps’ at the cost of the prized native fish species (Sugunan et al., 2000). This is one of the undesirable practices which greatly affect the biodiversity of indigenous species in inland water bodies. The environmental degradation and loss of existing wetlands are also a major constraint and adversely affect SIFs in turn. Overexploitation of species by local inhabitants reduces population size and disturbances in age structure and sex composition. Damming, deforestation, diversion of water for irrigation and conversion of marshy land and small water bodies are also the reasons for physical modifications of habitat of SIFs (Tewari and Bisht 2014). This affects the breeding ground and cause gill clogging of native small fishes. Use of pesticide in paddy fields is rampant all over India. Agrochemicals, metals, acids and phenol in high concentration cause mortality and affect the breeding process of fish (Kime 1995). Ambient temperature increases due to thermal pollution and reduces dissolved oxygen concentration leading to death of some sensitive fish species. SIFs are being caught before their maturity and considered as a major constraint in loss of SIFs (Suresh, 2010).
 
Consumption pattern
 
About 250 million children worldwide are estimated to be at the risk of vitamin A deficiency and an almost the same number are at the risk of deficiencies of minerals like iron, zinc, calcium etc. SIFs form a major component of food of those living around such water resources. Local people have knowledge about the health benefits of such species, for example, mola (A. mola), commonly found in eastern and North Eastern India. Those living in urban/suburban areas often expect variety of fish in addition to only carp species availability mainly for providing formidable amount of critical food source of very high biological value in the form of fresh fish for day to day consumption and offering larger benefits in terms of nutritional security particularly provision of household nourishment with regard to micronutrient availability so vital for healthy growth of children (Mukhopadhyay  2019).
 
Marketing channels
 
It usually passes through a number of levels. Each level contains a set of middlemen who perform the functions with the intention to bring the product closer to the point of consumption (Sinha, 2020). Nurullah et al., (2005) reported that the processors in consumer market received higher marketing profit followed by the primary market and secondary market, respectively. But, the availability of SIFs in the market is far below the demand and there is no specific marketing chain. There is a great seasonal and regional variation in the supply and type of SIFs. The peak harvest season of riverine SIFs is November-December. SIFs  from  the  floodplain  comes  to  the  markets between  May  and  December  with  a  peak  in  October-December.  SIFs from other water bodies are harvested between January and April. Fish price depended on size, season, availability and quality.  Low income,  lack  of  capital,  very  poor  or  no  handling preservation and processing facilities are the  uncertainty  in  SIF marketing and pricing  system, very  poor  educational  background  and  ill  health  are also  among  the  main problems in the livelihood of SIFs retailers. Ahmed and Hossain 2000 portray a bottleneck in the livelihood approach of fish farming and marketing system due to lack of access to livelihood assets for the poorer section of the community. Retail marketing of SIFs is preferred by the fishermen. Sometimes small fishes are vending door to door by the fishermen and women.
 
Nutritional value of SIFs
 
Food Security is the “adequate access to food for all people at all times for an active, healthy life” (Gross et al., 2010). Based on the ICMR-National Institute of Nutrition (Hyderabad) norm more than two-thirds of population in rural households in India was undernourished during 2009-10 (Chand and Jumrani 2013). Majority of the Indian rural women face nutritional deprivation since their childhood which is the major cause of malnutrition and under-nourishment of the women (Roy et al., 2015). Socio-cultural values are also biased against women (Anonymous, 1997) which are one of the major reasons of the malnutrition. The importance of mola (A. mola) has been highlighted as the richest source of vitamin (Alam, 1985). Consumption of these fish may be a simple and easy way to meet the vitamin-A deficiency and thus may be used as in curing the night blindness. Small fish are very rich in Zinc compared to food from other animal sources. Calcium absorption from small fish was comparable that from skimmed milk and that these fish may represent a good source of Ca (Hansen et al., 1998). The proximate biochemical composition of some small indigenous fish species were analyzed by Mazumder et al., 2008. Even the low market-value small species Esomus longimanus, contains 20.3 mg of zinc/100 g raw edible parts is commonly consumed by poor people in Cambodia, (Roos et al., 2007). SIF can serve as natural supplements for combating and preventing micronutrient deficiency as well as protein calorie malnutrition (Mahanty et al., 2014). Stansby 1954; Salam 1995 and Jacquot 1961 found variation in proximate composition of fish flesh with species variation, season, age and the feeding habit of the fish. The same observation was reported by Piska and Waghray 1989. Gopakumar 1997 studied the amino acid composition of some SIFs (Table 1). The successful linking of human nutrition and fisheries to address micronutrient deficiencies has relevance for other countries with rich fisheries resources, such as Cambodia and countries in the Lake Victoria region of Africa (Roos et al., 2007b). The nutrient content of some common SIF is mentioned in Table 2.

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Small fish as alternate livelihood
 
A livelihood comprises of capabilities and assets required for means of living. SIFs found in the vast inland water resources, provide not only nutrition but also livelihood opportunities and income to a large number of fishers. Studies in India have shown that the profit accruing to fishers is actually higher in the case of SIFs when compared to those from large cultured species. SIFs are also available in creeks, water channels, wetlands, paddy fields of coastal Sundarbans (Sinha 2017). Thus, if SIF is conserved properly, sustainable fisheries based on small indigenous fishes can provide an additional income or a source of alternate income to the people. Thus, food and nutritional security can also be ensured. SIF has the potential to increase the income of the fishermen community, which will empower the community to access education, health, nutrition and better living standards which ultimately can ensure food and nutritional security of the people. Mondal et al., 2020 recommended poly-culture of carps with mola for additional nutritional and economic benefits; field level household culture is highly suggested in Bangladeshi pond. Mola is very rich in micronutrients and high potential for polyculture with carps. It is compatible for production in all type of ponds, inundated water bodies, rice field connected ponds, beels. It also breeds in ponds and other water bodies, it is highly fecund fish species (1,000-20,000), breed several times in a year and matured at three months of age. It is not required further stocking if once stocked and conserved it properly. Saha and Barman 2020 promoted production and marketing of Mola and other Small Indigenous Species of fish in Bangladesh. They opined that many people partly or fully maintain their livelihoods through harvesting and selling of fish most importantly the SIFs by harvesting from the natural resources.
 
Integration of high priced small indigenous fish with conventional carp culture
 
SIF based aquaculture technology packages are developed for: Carp-mola polyculture, Mola-punti-carp polyculture, Carp-prawn-mola culture etc.  (Wahab et al., 2010). In an experiment it was reported that, when A. mola along with carp species was cultured has increased overall pond fish production (Roos et al., 2007). It was observed that the prices of these species were high, often higher than the prices of Indian Major Carps (Ahmed 2009), providing a source of supplementary income to rural households. Analysing the local demand for freshwater small indigenous fish species, the FAO (1999) also indicated the possibility of integration of polyculture system with such indigenous fish species. Sinha and Santra 2016 observed the better total fish production from culture of carps with mola than carps with chela. The same result was also observed by Roy et al., 2003 and Kohinoor et al., 1998. Dewan et al., 1991 and Kohinoor 2000 observed a severe competition for food between planktivorous native and exotic carps. In polyculture of carps while phytoplankton grazer mola was added, it reduced the food availability for rohu. Catla feeds in the upper layers of the water column, mainly capturing zooplankton (Miah and Siddique 1992; Jhingran and Pulin 1985). The addition of mola, puntius or chela which also grazes on phytoplankton but mainly feeds on the bottom and on detritus, indirectly reduced food availability for catla reducing algal food of zooplankton and puntius also by removing benthic stages of zooplankton (Kohinoor 2000). The addition of highly efficient grazer silver carp in Indian Major carp culture system reduced food availability for all fish grazers (Milstein 1992). The fishes living in the aquatic ecosystem have specific feeding habit and preference for the food (Ahmed et al., 2010). They have feeding interrelationship among them and therefore, the knowledge of feeding ecology of the fishes must be studied for the individual integration. Wahab et al., 2011 proved that manipulation of species composition is one of the useful tools towards improving fish yield and corresponding income. Nandi et al., 2012 opined that there is need to study the feeding ecology of SIFs to understand food partitioning and habitat preference within and between the fish species for better culture cum conservational approach.
 
Commercially important SIFs of ornamental value
 
The top ten groups of ornamental fishes are the livebearer fish like guppy, molly, platy, swordtail and egg layers like goldfish, catfish, gourami, tetra, loach, cichlid and the barb. Of the 30-35 species that are the favorites of aquarists, only a few are of Asian origin-Brachydanio rerio and Pethia conchonius being the most common. About 30 species of highly priced ornamental fishes were identified for culture including Pethia denisoni. The hill stream fishes belonging to the genera Balitora, Barilius, Garra, Homaloptera, Lepidocephalus, Nemacheilus and Psilorhynchus are considered to be coldwater species. Some of the other endemic species from the south are known to have an immense potential for export. Sinha (2017) could enlist small indigenous fish as exportable ornamental fish (Table 3). A few of the indigenous freshwater ornamental fish are bred in captivity.


 
Conservation
 
SIF has the potential to increase the income of the fishermen community, which will empower the community to access education, health, nutrition and better living standards which ultimately can ensure food and nutritional security of the people (Roy et al., 2020). The  loss  of  aquatic  biodiversity  due to anthropogenic activities is  continuing  at  an  alarming  rate (Moyle and Moyle, 1995). About 20 per cent of the world’s ichthyofauna is already extinct or going to be extinct (Moyle and Leidy 1992). Lakra et al., (2010) has compiled a list of 120 freshwater threatened fish species in India including 5 species of Channa and 14 species of Puntius. Dubey et al., 2014 suggested that A. mola and P.ticto can potentially be used as the candidate species for aquaculture diversification in slightly saline water of Sundarbans. The majority of SIFs are caught before their maturity. Sinha et al., 2014 reported that there is a significant reduction in availability of native small fish Amblypharyngodon mola, S. bacalia, Mystus vittatus, Puntius sarana, Nandus nandus in the water channels of Sundarbans. Patra et al., 2005 reported that SIFs like H. fossilis, A. gagora, Mystus. vittatus, P. canius, Ailia coila, Clarias batrachus are vulnerable species in Sundarbans.

In situ conservation can be done through their maintenance within natural or man-made ecosystem in which they occur. A trial was conducted for initiating in-situ conservation in Sundarbans for ensuring the community participation in conserving the small indigenous fishes and observed encouraging results (Sinha and Roy 2016).

Eco-restoration can be done by ranching of SIFs through active people’s participation in the fresh water canals or water channels.  Enforcement of laws and regulation to protect SIFs particularly in breeding, regulation of small meshed nets, selection of water bodies as sanctuaries, intensive aquaculture and introduction of exotic fishes must be reduced, mass awareness generation about nutritional benefit of SIF, institutional mechanism to popularize SIF for nutritional security as well as alternative livelihood needs attention.
 
Awareness and capacity building
 
Sensitizing the community to include SIFs in their diet attracts small scale entrepreneurs to culture SIF for their nutritional security and livelihood was attempted by Sinha et al., 2017. Awareness and capacity building programme are the need to contribute in developing policies and legislative measures to ensure the conservation and promotion of SIFs, both in capture and culture systems, as well as access of disadvantaged groups, particularly women. It is important to mention that traditional conservation ethics could still protect much of the country’s valuable biodiversity, if local community actively involve themselves in such measure with a share in financial benefit (Deb and Malhotra 2001). Public awareness is the necessity of conservation of indigenous fish diversity and wise management of habitats needs to be created through mass media.