African Catfish: Is it a real threat in Nepal?

Introduction

African catfish known as Clarias gareipinus of Claridae family is a carnivorous fish with grey black appearance, which mostly lives in freshwater rivers, lakes and swamp. They are the air breathing fish, also called sharptooth catfish. They are commonly called ‘Mangur’ in the local Nepali language.

History of African Catfish Farming:

African Catfish are native to Africa and the Middle East. In the beginning they were farmed in around 1960. In 1980, it was introduced for aquaculture purposes in Brazil, Vietnam, Indonesia and India. In Nepal, it was introduced in 1996-97 by fry traders from India and Bangladesh (FAO).

Morphology

C. garipinus are grey, brown to black in color. It is broad in the anterior part and shrunken in the posterior end. Head is flattened while tail is tempered. It consists of white belly. Average length of fish is 50-70 cm and it can be harvested in 7-8 months which is about 1 kg. It has been recorded to weigh up to 60 kg in weight. Intramuscular bones are absent. Sexual dimorphism is not seen but male is larger than females.

Habitat

African catfish is a nocturnal fish mainly found in freshwater. It is bottom dweller and feeds on natural zooplanktons and other small fishes in natural habitat.

Rearing of Catfish

Catfish rearing is flourishing day by day. It can be reared in earthen ponds, cemented ponds and bioflocs. It grows fast and has a hardy nature to tolerate harsh conditions. pH of water should be ranged between 6.5-8. They are able to live in turbid water and can tolerate 8-35 C. Optimum temperature for growth is 20-30 C (Teugles 1986) . They mostly live in the bottom as they are air breathers so they come to the surface timely (Pienaar 1968). It can be raised in high density resulting in higher yield. In Nepal it is mostly reared in Terai and in some parts of hilly region. It has uplifted the socio-economic status of the farmers.

Positive attributes to farming

Fish farming has been an important sector in agriculture. In Nepal most of the fishes are imported from India. So, by farming the African catfish and promoting the fish market will benefit the economic status of both farmers and country. Investing in catfish is cheap for farmers as the fingerlings are cheap and can be farmed in a high temperature range. Large quantities can be farmed in small spaces. It can be produced 30-50 ton/ha/year (M.K Shrestha, 2015). It can be sold live in the market and fetches a higher price than Tilapia.

Market of African Catfish

Internationally C .garipinus has been produced in Nigeria, Netherland, Hungary, Mali, Brazil, Cameroon, Thailand and South East Asia. In Nepal it has a great potential in the growing fish market. Market of African Catfish was seen after 2000 A.D globally. It has been growing exponentially since then. About 2,00,000 tones were produced in 2010 and it were increased to 2,50,000 tones in 2015 and about 3,00,000 tones in 2020 (FAO). They are been preferred by the customers as they do not have muscle bones and mostly sold live in the market.

In Nepal, the market of fish depends on local and domestic markets only. It is not so systematic because it lacks marketing infrastructure, strategy and facilities. Despite these shortcomings the market is still growing. The African catfish is produced around 2500 metric tons yearly and consumed locally. There are 1681 fish shops and 69 live fish selling stalls (NFS, 2017). Farmers could gain Rs.200-300 ($2-2.5) per kg African Catfish on the wholesale market.

Benefits for the consumers

Fish meat is among the most valuable food products. Muscle of fish consists of high grade proteins. It consists of easily digestible fat, minerals, fat soluble vitamins A, D and water soluble vitamin B. The meat of African catfish possesses all essential amino acids. It also consists of a high level of mono and poly-saturated fatty acid containing linoleic acid much higher than pink salmon fish, large amounts of oleic acid which prevents cardiovascular disease and omega 3 and omega 6 fatty acid. Meat of African catfish can be classified as the full package of proteins as it contains all amino acids and compositions. (L. Shadyeua 2019).

Is it a real health threat?

In Nepal catfish is reared by feeding the slaughter house wastage. Catfish fed with chicken wastage has been found the traces of Lead (Pb). However, as the TDI (Tolerable Daily Intake) is below 1, (Singh et al ARRB: 41-58,2015) It is found to be lower risk and consumable. (article no ARRB 2015.062). So, it is concluded that it hasn’t caused any adverse health effect.

Threat of African Catfish in Nepal

African Catfish are farmed mostly in the Terai region. Ponds of terai are mostly earthen and muddy. In the days of flooding the ponds get flooded and the fish reach the rivers. It can release 4,00,000 eggs in a single season. African Catfish have tendency to grow fast and increase rapidly in all ecosystems due to its availability of producing high numbers of offspring and higher survival rate. It is highly carnivorous in nature and a threat to the ecosystem. Another effect is hybridization to the local breeds which can affect the gene pool.

Banning of African Catfish in Nepal

No, legal law and official paper has been found in Nepal for banning the African catfish. In India the High Court has implemented the ban across the country with the reason that it could pose threat to indigenous fish and aquaculture diversities.

Is it necessary to ban it in Nepal?

If the farming is done in a sustainable way maintaining ecological balance, then the farming of African Catfish can be a boon for Nepali farmers. Government should make a policy regarding the farming of African catfish. The modern systems like cemented ponds and bioflocs pose no threat to the environment. Conventional ways of farming should be improved. Then, there is no need to worry about the African catfish. As a result, many farmers can benefit greatly.

Refrences:

Shukla Gandaki Agriculture Production and Research Pvt. Ltd, (Pokhara-33, Lamgadi)

Lamgadi krishi farm Pvt.ltd (Pokhara-33, Lamgadi)

The introduction of the African catfish Clarias gariepinus (Burchell, 1822) into Brazilian inland waters: a growing threat (Gecely Rodrigues Alves Rocha, 2008)

African Catfish A boon or bane for environment: A critical analysis (Pyali Chatterjee, 2019)

An Appraisal of Introduced African Catfish Clarias garipinus (Burchell, 1822) in India: Invasion and Risks (ARRB, 2015)

https://animaldiversity.org/accounts/Clarias_gariepinus/

Charectarization of the Nutriotional Quality of meat in some species of catfish: An Overview (CAIALL-07/2011)

Effects of feed composition on the nutritional value of meat of African Catfish (L.A Ahadieva)

Forecast of the nutritional value of catfish (Clarias gariepinus) in the spawning period (l. Shadyeva 2019)

FAO Fisheries & Aquaculture – Cultured Aquatic Species Information Programme – Clarias gariepinus (Burchell, 1822)

Aquaculture Development in Nepal and Current Needs (M.K Shrestha, 2015)

M.A. Husen (2019) Int. J. Appl. Sci. Biotechnol. Vol 7(1): 1-5. DOI: 10.3126/ijasbt.v7i1.22938

Writer: Achyut Babu Acharya (Student, V Semester Nepal Polytechnic Institute, Bharatpur Nepal)