Impacts of Inclusion of Column Feeder Rohu (Labeo Rohita) at Different Stocking Densities on Growth and Production in Freshwater Prawn-Finfish Polyculture System

Abstract

The research investigated the impacts of inclusion of column feeder rohu (Labeo rohita) on growth and production in freshwater prawn-carp-mola polyculture system for a period of 172 days. Four stocking densities of Rohu were maintained as 500, 1,000, 1,500 and 2,000 ha -1 in treatment R 500 , R 1000 , R 1500 and R 2000 , respectively in triplicates. All ponds each 120 m 2 were stocked with juvenile freshwater prawn (Macrobrachium rosenbergii), silver carp (Hypophthalmichthys molitrix), catla (Catla catla) and small fish mola (Amblypharyngodon mola) at the fixed stocking densities of 20,000, 1,500, 1,000 and 20,000 ha -1 , respectively. Prawns were fed with pelleted feed twice daily started with 10% and gradually reduced to 3% of body weight and continued throughout the study period. All fish were fed with mixture of soaked rice bran and mustard oilcake (2:1) at the rate of 3% of the body weight daily. All the water quality parameters and chlorophyll-a were measured. The density of rohu significantly (P<0.05) influenced the survival rate, growth and production of freshwater prawn. Catla and Mola production were affected adversely with increasing rohu density. The production of rohu increased with increasing density although the individual weight decreased. The combined production of all finfish was significantly lower in R 0 whereas, the combined production of all species including prawn did not differ significantly (P<0.05) among the treatments. The treatments R 0 and R 500 fetched higher net profit without significant difference between them. Therefore, inclusion of rohu at a density of 500 ha -1 may be recommended for prawn-carp-mola polyculture.

Seaweed,Enteromorpha intestinalis, as a Diet for Nile TilapiaOreochromis niloticusFry

“…Overall, NO 2 -N and TAN concentrations increased and DO decreased over time (Figure 1). Treatment × time interaction was significant on all measured water-quality parameters except pH (Ahsan et al 2013;Siddik et al 2014). Dissolved oxygen, pH, nitrite-N, and TAN varied over the experimental period between 5.2-6 mg l −1 , 7.6-8.2 mg l −1 , 0.02-2.5 mg l −1, and 0.01-1.2 mg l −1 , respectively.…”

Preliminary assessment of the Gut weed Ulva intestinalis as food for herbivorous fish

“…Water quality parameters Daily water temperature, dissolved oxygen, and pH over three experiments fluctuated in the ranges of 26.5-30.2°C, 4.90-5.66 mg/L, and 7.1-8.3, respectively. These factors were generally within the suitable range for tropical fish growth (Boyd 2003;Siddik et al 2014b;Ahsan et al 2013). However, the mean concentrations of dissolved inorganic nitrogen such as NO2 and TAN ranged from 0.04 to 1.85 mg/L and 0.02-0.97 mg/L, respectively.…”

Fish Community Structure of Sandha River: A Link Analysis towards Fisheries Management and Conservation

“…Margalef in the study area was ranged from 4.6 to 8.471 which indicated the river had healthy to high-quality food chains. In general, diversity indices value varied depending upon the number of species as well as a number of individuals in each fish species [11,32,41].…”

“…Thus, the river has great influence to change life pattern and sustain of riverine population community the southern coastal region of Bangladesh primarily depend on resources from the river. But at the meantime, the worthwhile aquatic resources of Sandha River are in declining trends like others water resources of Bangladesh due to both anthropogenic activities and environmental alterations [4,10,11]. Very earlier study by Hanif et al [12] identified total 26 threatened fish species from Sandha River and found environmental degradation and over-exploitation using restricted fishing gears was the important factors for threatening the ichthyofaunal community.…”