Effects Of Fertilization And Low-Cost Feed On Golda-Carp Polyculture

Abstract

A preliminary study was conducted on the effects of feed and fertilizer on growth of goldacarp polyculture in 6 (six) ponds at Khulna university campus during the period from 3 September, 2002 to 3 march, 2003. Indian major carps (Labeo rohita and Catla catla) and golda (Macrobrachium rosenbergii) were stocked with a percentage of 33.3,44.4 and 22.2 respectively. Artificial feeds were given in 3 ponds (treatment-I) and fertilization was done in other 3 ponds (treatment-2). Artificial feed consisting of rice polish (40%), soyabean cake (10%), wheat flour (15%), wheat bran (20%), mustard oil cake (5%) and snail (10%) was applied in II at the rate of 5% of the total fish biomass. Only fertilization with 200g raw cow dung/decimal/day; 7g ISP Idecimal / day; and 3g Urea Idecimal / day were given in 12. The initial weight of rohu, catla and golda were 18± 5.02 g, 11.94± 4.25 and 9.94± 3.33 g respectively in T1 whereas the fmal weight of rohu, catla and golda were 120 ± 17.17, 60.28 ± 13.23 and 58.33 ± 16.98 g respectively. In 12 the weight of rohu, catla and golda were 20± 7.17, 11.94± 3.49 and 9.78± 3.46 g respectively at the time of stocking. After 180 days of culture the final weight ofrohu, catla and golda were 97 ± 32.00, 53 ± 14.14 and 51.94± 16.73 g respectively in 12.The net gain in weight over a period of six months were found to be 101.l1, 48.33 and 48.39 g for rohu, catla and golda, respectively in II whereas the net gain in weight were 77 .50,41.39 and 42.l7 g for rohu, catla and golda respectively in T2. In T1 and 12, the average growth rates were 0.56 and 0.43 g/day for rohu, 0.27 and 0.23 g/day for catla, 0.27 and 0.23 for golda respectively. Some physico-chemical factors such as water temperature, transparency, dissolved oxygen and pH were recorded fortnightly. Except water temperature in winter, the physico-chemical condition was found to be within the range of optimum level. The growth rates of all species are seriously hampered by low temperature in December and January. The result of the study showed that the growth performance of rohu, catla and golda slightly higher in II where supplementary feed was used. But polyculture with only fertilization may acceptable for poor marginal farmer who are unable to buy feed for fish.