The New Nation - Internet Edition

Professor Dr. Md. Idris Miah

Bangladesh is fortunate enough having an extensive and huge water scattered all over the country in the form of small ponds, beels, lakes, canals, small and large rivers and estuaries covering an area of about 4.34 million hectares (Mazid, 2002). The inland aquatic habitats of Bangladesh are rich in faunal biodiversity containing at least 265 species of finfish, 63 species of prawn, several species of turtle, tortoises, fresh water mussels and other living aquatic organisms which are commercially important (Rahman, 2005). 93% of the inland open water bodies comprise open waters and 7% closed water bodies (DOF, 2005).

Presently fish and fisheries sector contribute 63% of total animal protein intake, 4.92% GDP, 23% agricultural production and 5.77% of foreign export earnings of the nation (DOF, 2005). At present 1.4 million peoples are engaged full time and 12 million as part time in fisheries sector in the country for livelihood and trade. Another 3.08 million fish and shrimp farmers are cultivating fish and shrimp at both subsistence and commercial level (Mazid, 2002). About 13% of the rural households are implicated in this sector and it provides employment to about 7% of the population (Haque, 1996). But fish stocks are being lost due to over exploitation, indiscriminate and distinctive fishing activities, ecological imbalance, erosion, siltation, breeding ground destruction and also due to the human development activities. Recent estimates suggest that worldwide 20% of all freshwater species are extinct, endangered as vulnerable (Moyle and Leidy, 1992).

According to IUCN (2000) out of 266 fish species in Bangladesh (freshwater and brackish), 12 are critically endangered, 28 endangered and 12 are vulnerable and more are under increasing threat for sustainability (Ahmed and Wahab, 2003).

Boal is one of the endangered species. Bangladesh Agricultural University has brought a good news in this aspect. A team of Scientists led by Prof. Dr. Md. Idris Miah, Department of Fisheries Management, BAU has got the first success in induced breeding of Boal fish in Bangladesh scientifically. Prof. Dr. Md. Idris Miah, Professor Dr. Somen Dewan were assisted by Ph.D. fellow Md. Mokhlesur Rahman and S.M. Farid, M.S. student Md. Sayeed Harun, Harun Ar Rashid and Nasimul Islam and Lab Technician Azadul Islam. The project entitled, "Development of Induced Breeding Technique, Larval Rearing and Cultural Management of Wallago attu (Bloch)" funded by the Ministry of Science and Information & Communication Technology, Project Director, Prof. Dr. Md. Idris Miah and his Research Assistants achieved this success after long laborious works.

Scientific name of 'Boal' fish is Wallago attu (Bloch), and this fish belongs to the family Siluridae. In adult, male fish is smaller than female. Their body is elongated, head depressed, tail compressed. Upper and lateral part of head covered by osseous plates forming a case. Accessory dendritic branchial organs attached to second and fourth branchial arches. Cranial roaf with two fortanels are frontal commencing from between eyes in front region, other much shorter in occipital region. Mouth transverse, upper jaw slightly longer. Anterior nostrils short tubes upper lip, Posterior nostrils more or less rounded slits behind nasal barbells. Eyes small with free orbital margin.

Barbels 4 pairs, nasal pair extends to near occipital process, maxillary pair extends to the middle or end of pectoral fins, mandibular pairs shorter. Vili form teeth in a creseentic land an jaws. Dorsal and annal fins long composed entirely of soft rays. Pectoral fins rounded, its spine unindented. Caudal rounded, free from vertical fins.

Previously they were found in plenty throughout Bangladesh in the rivers, canals, beels, haors etc. But at present their abundance decreased tremendously. They breed from May to July with the approach of monsoon in shallow waters inundated paddy fields and similar bodies of water.

Project Purpose:

The research work is aimed at developing suitable technology for breeding, hatching and larval rearing of Boal (Wallago attu) that could be disseminated among the hatchery managers and nursery operators. The specific objectives are as follows-

(i) To study the complexity of breeding biology of Boal.

(ii) To successfully breed the Boal (Wallago attu) species by using pituitary gland (PG) extract and synthetic hormones as inducing agents.

(iii) To determine the fertility and hatching rate in relation to varying water temperature and time.

(iv) To study the embryonic development process of Boal.

(v) To study the effects of different natural and artificial feeds on the growth and survival of the larvae for rearing them up to the stockable size.

(vi) To study the effects of different stocking density on the growth and survival of larvae.

(vi) To assess the growth performance and yield of the Boal under monoculture system.

Breeding Technique:

On March 2008, 40 pieces of brood fish (Wallago attu) were collected from the Guzadia beel under Karimgonj thana in Kishoregonj district. Among them 22 pieces were female and 18 pieces were male. Fishes were brought in live condition and they were kept into the water containing large drum. Then they were brought by truck and water was changed several times and adequate care was taken so that no oxygen deficiency occur. Fishes were kept into the Fisheries Field Laboratory Complex pond. After acclimatization rearing was started with supply of good quality live feed, such as jat punti, tit punti, fry of silver carp and prawn as a feed of these brood fishes. Besides, brood tilapia also stocked in the pond which produced larvae, which were used as food of Boal.

A series of experiments were done with different doses of PG and H C G hormones in the trial and error basis and finally PG showed better performance.

Brood fish are rearing for the nex1 year experiments in a wide scale due to ending of breeding season in this year. In case of getting fund lately and some other practical limitations research works have been hampered in this year. We are hopeful that it is possible to overcome these problems. Growth rate was found encouraging. If we can develop low cost supplementary feed for boal fry, then monoculture of boal in ponds would be easy, popular and profitable like pangus culture in Bangladesh.

The overall goal of the proposed study is to bring socio-economic upliftment of the rural fish farmers which will be reflected in term of their increased fish production, mitigation of malnourishment problem, supply of proteinous food, increased income, creation of employment opportunity, ensuring food security and maintaining of biodiversity.

(Prof Dr. Md Idris Miah is the Project Director, Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh.)