Bionomics Of Notopterus Notopterus (Pallas, 1769)

Abstract

The bionomical study of N notopterus is carried out during January, 2005 to December, 2006. The present research findings are presented in 195 pages including 22 tables, 36 figures and I 3 plates. The relationship model equations among different body length parameters are found highly significant. The growth curve model (GCM) for summer, rainy and winter season is established as TW=0.00771 TL3·045, TW=0.00441TL3·219 and TW=0.00884 TL2998 respectively where in male, female and combined sexes it is established as TW=0.00781TL3·031, TW=0.00844TL3·022 and TW=0.00813TL3·026 respectively and found highly significant to asses the growth variation of the population. The species showed female dominating distribution including homogeneity in yearly distribution. The Fulton's, allometric and relative condition factors showed variation in different season and sex maintaining a similar pattern indicating gradual development of gonad in relation to the sexual cycle. The fish feed on a large variety of food items viz. fish and body parts (16.89%), crustaceans (20.43%), aquatic insects (20.01%), annelids (2.19%), molluscs (1.41 %), debris and mud (16.68%), semidigested mater (11.49%), plant and plant parts (9.60%) and gravel and stones (1.30%). The TL-ACL relationship model equation is established as ACL = 2.065 + 0.326 TL which was positively correlated and statistically significant. The average value of TL-ACL ratio (1 g().43) revealed carnivorous habit of the fish. The gonads are found unpaired having short ducts which originate from the left abdominal cavity beside the alimentary canal and bellow the kidney. The mean length and weight of ripe ovary are found as 4.37 ± SE0.05cm and 16.37 ± SE0.56g respectively. The ova are found larger with a mean diameter of 3.07 ± 0.02mm in ripe stage. The fish is low fecund and the absolute fecundity is ranged from 651 to 2250 with a mean of 1598.18 ± 42.47. The breeding period extend from May to September. No methodical marketing channels are observed for N notopterus; channels that have been observed comprise a few intermediaries (e. g. 'Farias', 'Beparis', 'Aratdars' and Retailers) in between fishermen and the consumers. Benefit of fishermen is correlated with the length of marketing chain. The average retail price is found to vary due to season and marketing costs. The fish is able to breed naturally in stagnant water of carp polyculture system. The sandy-loam soil of the pond, submerged vegetation and suitable water quality enhanced the breeding process though random operational activity of carp polyculture system destroys breeding grounds and hampers parental care. But the findings of two years trial conclude for strong potentiality of natural breeding of N notopterus which may play an important role in production and conservation of the species.