Food and feeding habits of for M. aral were studied by examining a total of 421 digestive tracts during August, 2008 and July, 2010. It is very important to know the feeding habits of the fish in the natural environment in order to conduct stock enhancement by releasing the seedlings, because prevention of starvation, improvements of their growth and effective management can be conducted from this knowledge. The results reveals that the lowest value of relative length of gut (RLG) was found as 0.58(±0.09) in 27-32 cm whereas the highest values as 0.62(±0.12) in 7-12 cm group. Fullness of gut was recorded as18.38% (full); 9.18% (¾ full); 11.23% (½ full); 12.54% (¼ full); 19.77% (nearly empty) and 28.9% (empty).

Abstract:Length-weight relationship of Macrognathus pancalus had been carried out from two different waterbodies of upper Assam during 2009-2011. The pool data for the co-efficient of regression (b) was recorded as 1.408 in juveniles; 2.977 in males; 3.034 in females. It reveals that females have better growth than males and juvenile. The 'b' for males was found to be minimum (1.408) in 6-9 cm and maximum (3.024) in15-18 cm whereas, for females the lowest (1.807) in 9-12 cm and highest (3.202) in >15 cm groups. In different seasons, the 'b' value ranged from 2.982 (premonsoon) to 3.253 (winter) for males while for females, from 2.825 (post-monsoon) to 3.571 (winter). It indicates that both the sexes did not follow the cube law (b=3). The higher condition factor 'K' for males (4.622) and females (4.362) were observed in 9-12 cm and lower values for males (4.128) and for females (3.961) were recorded in 12-15 cm and >15 cm length group. The maximum (4.282) and minimum (3.686) of 'K' for males were recorded in post monsoon and pre-monsoon while in female, the maximum (4.376) in monsoon and minimum (3.913) in winter. It reveals that the species were in good conditions. The 'r' values for in all cases were found to be highly correlated between length and weight.

No abstract

Abstract:The investigation has been carried out from different landing site of the Brahmaputra River at Dibrugarh, Assam, India during February, 2014 to January 2015. As a whole, the relative length of gut (RLG) value was found to be highest during pre-monsoon and lowest during winter season. Among the examined species, Trichogaster fasciata was recorded as highest RLG value (5.74) and the lowest (1.10) was recorded in Mystus tengara. The value of RLG reveals that the feeding habit shows a variation from species to species. In case of gastrosomatic index (GSI), out of the examined species, Esomus danricus was found to be the highest (6.5) during pre-monsoon and Osteobrama cotio was lowest GSI (2.32) during winter season. The feeding intensity was found to be more or less similar in all the species. Again, in relation to the growth co-efficient 'b' of all the examined species, Puntius sophore was recorded as highest 'b' value (3.31) during monsoon while Osteobrama cotio was recorded as lowest (2.50) during winter season. Further, it predicts that the examined fish species did not follow the cube law and showed the allometric growth. The highest (1.85) condition factor (K) was recorded in P. sophore and observed in monsoon. In case of its lowest (1.0) was recorded in Salmostoma bacaila and observed in winter seasons. They were found in health and well-being condition and calculation of growth coefficient. After washing the specimen were preserved in 5% formalin for further study. For the study of feeding habit, length-weight relationship and condition factor, total length of the individual fish was measured from the tip of the snout to the extended tip of the caudal fin; total body weight was measured to the nearest 0.1 gm in electronic balance. Relative length of gut (RLG)The alimentary canal of the fish specimen was dissected out, uncoiled it and cleaned off the fat body and other associated gland from the alimentary canal. The extended alimentary canal was then measured in measuring scale followed by taking the weight of the alimentary canal in the electronic weighing balance. The relative gut length is calculated by using the formula of AlHussainy (1949): RLG=GL/TL, where, GL=Gut length of the fish; TL=Total length of the fish. Gastrosomatic index (GSI)GSI is calculated by taking the ratio between gut weight and total body weight of the fish specimen and multiplied by 100 (Biswas, 1993). Length-weight relationshipThe relationship between the total length and the total weight were determined by using the formula as proposed by LeCren (1951): W=aL b where, W=weight in gram; L=Total length of the fish specimen in cm; a and b is initial growth and growth coefficient respectively. To make the relationship linear,

Exostoma kottelati, new species, is described from the Ranga River, Brahmaputra basin, in Arunachal Pradesh state, northeastern India. It differs from congeners in the Brahmaputra River basin in having a longer adipose-fin base (33.4–36.0 % SL vs. 23.4–32.9), a greater (except E. mangdechhuensis) pre-pelvic length (45.6–47.3 % SL vs. 39.3–44.6) and a greater pre-anal length (73.9–76.5 % SL vs. 62.2–70.1). It further differs from all known congeners by the following unique combination characters: the adipose fin is distinctly separated from the dorsal procurrent caudal-fin rays, pre-dorsal length 38.9–41.7% SL, adipose-fin base length 33.4–36 % SL, caudal peduncle length 18.7–21.1 % SL, caudal peduncle depth 8.8–9.5 % SL, and body depth at anus 12.5–13.5 % SL. This is the fifth species of Exostoma known from the Brahmaputra River basin.