Prospects and potentials of fisheries in the North Eastern States of India

Since this region is a hilly land• locked area, only freshwater resources are available which mainly comprise rivers (18,968 kmJ, reservoirs (8,091 hal. bheels/Lakes (14,3491 hal and tanks and ponds (42,782ha). Besides. there is a vast extent of paddy fields, lowlying areas and forests which cor.tribute additional resources of around 94.577ha in the region

Biofilm developed on plant substrates enhances growth and survival of post larvae of Macrobrachium rosenbergii

A five-week laboratory experiment was conducted to evaluate the efficacy of plant-based substrates for biofilm production and their effect on water quality as well as growth and survival of freshwater prawn Macrobrachium rosenbergii (De Man, 1879) postlarvae. The experiment consisted of three treatments with a control, each with three replicates following a completely randomized design. The substrates evaluated were dried sugarcane bagasse (T1), paddy straw (T2) and Eichhornia (T3). Tanks without substrates acted as control. Seven days after the introduction of substrates at the rate of 300 g /tank, post-larvae were stocked at 40 nos/m2. The mean initial length and weight of the post-larvae was 10.3 mm and 0.008 g, respectively. The post-larvae were fed with commercial pellet feed (30% protein) at 20% of initial biomass. Results revealed significantly higher (p<0.05) levels of total ammonia- nitrogen, nitrite-nitrogen and nitrate-nitrogen in the control tanks (0.07 ±.004 mg L-1; 0.03 ±.01 mg L-1; 1.40 ±.05 mg L-1, respectively) compared to treatment tanks. Addition of natural substrates enhanced survival and growth of post-larvae with highest growth recorded in paddy straw (0.15 ±0.05 g) followed by sugarcane bagasse (0.14±0.04 g) and Eichhornia (0.10±0.01 g) treatment. The enhancement of growth of PL in natural substrate corresponds to the heterotrophic bacteria that are using the substrate, probably as a food resource and as a probiotic. Further, there was no water exchange during the experimental period, which indicated that the presence of a biofilm reduces the necessity of water exchange and saves water during the postlarval rearing of M. rosenbergii at this density

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Not AvailableSince this region is a hilly land• locked area, only freshwater resources are available which mainly comprise rivers (18,968 kmJ), reservoirs (8,091 hal). bheels/Lakes (14,3491 hal) and tanks and ponds (42,782ha). Besides. there is a vast extent of paddy fields, lowlying areas and forests which cor.tribute additional resources of around 94.577ha in the region.Not Availabl

Not Available

Not AvailableSince this region is a hilly land• locked area, only freshwater resources are available which mainly comprise rivers (18,968 kmJ), reservoirs (8,091 hal). bheels/Lakes (14,3491 hal) and tanks and ponds (42,782ha). Besides. there is a vast extent of paddy fields, lowlying areas and forests which cor.tribute additional resources of around 94.577ha in the region.Not Availabl

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Not AvailableA five-week laboratory experiment was conductedto evaluate the efficacy of plant-based substrates forbiofilm production and their effect on water qualityas well as growth and survival of freshwater prawnMacrobrachium rosenbergii (De Man, 1879) post-larvae. The experiment consisted of three treatmentswith a control, each with three replicates followinga completely randomized design. The substratesevaluated were dried sugarcane bagasse (T1), paddystraw (T2) and Eichhornia (T3). Tanks withoutsubstrates acted as control. Seven days after theintroduction of substrates at the rate of 300 g /tank,post-larvae were stocked at 40 nos/m2. The meaninitial length and weight of the post-larvae was10.3 mm and 0.008 g, respectively. The post-larvaewere fed with commercial pellet feed (30% protein)at 20% of initial biomass. Results revealedsignificantly higher (p<0.05) levels of total ammo-nia-nitrogen, nitrite-nitrogen and nitrate-nitrogen inthe control tanks (0.07 ±.004 mg L-1; 0.03 ±.01 mgL-1; 1.40 ±.05 mg L-1, respectively) compared totreatment tanks. Addition of natural substratesenhanced survival and growth of post-larvae withhighest growth recorded in paddy straw (0.15 ±0.05g) followed by sugarcane bagasse (0.14±0.04 g) andEichhornia (0.10±0.01 g) treatment. The enhancementof growth of PL in natural substrate corresponds tothe heterotrophic bacteria that are using thesubstrate, probably as a food resource and as aprobiotic. Further, there was no water exchangeduring the experimental period, which indicatedthat the presence of a biofilm reduces the necessitiy of water exchange and saves water during the post-larval rearing of M. rosenbergii at this density.Not Availabl

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