Effects of Duckweed (<i>Lemna minor</i>) as Supplementary Feed on Monoculture of Gift Strain of Tilapia (<i>Oreochromis niloticus</i>)

Abstract

An experiment was conducted for a period of 135 days on the effect of duckweed (Lemna minor) as supplementary feed on monoculture of GIFT strain of tilapia (Oreochromis niloticus). The experiment had two treatments, each with three replications. In treatment-1 ponds were supplied with duckweed as supplementary fish feed and in treatment-2 ponds were kept as control (without supply of duckweed). Ponds were stocked at a stocking density of 150 fingerlings per decimal. The ponds were fertilized fortnightly with poultry dropping at the rate of 5 kg/decimal, urea 60g/decimal and TSP 90g/decimal. Duckweeds were supplied to the ponds (treatment-1) at the rate of 60% of the total body weight (wet weight basis) of the fish. During the experimental period, the ranges of physico-chemical parameters viz, water temperature, transparency, dissolved oxygen, pH, total alkalinity, free CO2, PO4-P, and NO3-N were within the productive limit and more or less similar in all the ponds under treatments 1 and 2. There were 24 genera of phytoplankton under 5 major groups and 10 genera of zooplankton under 3 major groups were found in the experimental ponds. Mean survival rates in treatments 1 and 2 were 85.34% and 83.68% respectively. Specific growth rate (SGR, % per day) of the fish in treatments 1 and 2 were 1.90% and 1.60% respectively. Calculated net production of the fish in treatment-1 was 5.03 ton/ha/yr and in treatment-2 was 3.11 ton/ha/yr. By t test it was found that the net production of fish in treatment-1 was significantly (p&lt;0.05) higher than that of treatment-2.DOI: http://dx.doi.org/10.3329/pa.v18i2.18201 Progress. Agric. 18(2): 183 - 188, 2007

Effects of artificial feeds on growth and production of fishes in Polyculture

“…Within limit productive ranges of such water quality parameters have also been observed by a number of authors (Uddin et al, 2007;Chowdhury et al, 2008;Uddin et al, 2012;Rahman et al, 2012;Talukdar et al, 2012;Siddika et al, 2012;Nupur et al, 2013) in the aquaculture ponds of BAU area which are in conformity with those of the present study.…”

Abundance of Plankton Population Densities in Relation to Bottom Soil Textural Types in Aquaculture Ponds

“…Within limit productive ranges of such water quality parameters have also observed by a number of other authors (Wahab et al, 1995;Kohinoor et al, 1998;Haque et al, 1998;Uddin et al, 2007;Chowdhury et al, 2008). Similarly, the ranges of pH, organic carbon (%), organic matter (%), available phosphorus (ppm) and total nitrogen (%) of pond bottom-soil in the aquaculture ponds were within the suitable ranges and showed no abrupt changes during the experimental period in all the treatments (Table 2).…”

“…More or less similar numbers of genera were recorded in the plankton population by a number of authors in the ponds of Bangladesh Agricultural University campus (Dewan et al, 1991;Wahab et al, 1995;Kohinoor et al, 1998;Uddin et al, 2007 andChowdhury et al, 2008). Table 4.…”

Fish growth, yield and economics of conventional feed and weed based polyculture in ponds

“…Researches carried out on the application of weed have so far been centered on the waste water treatment (Oron 1994;Alaerts et al 1996). With a few exception of some efforts on duck weed based aquaculture (Azim and Wahab 2003;Uddin et al 2007), no comprehensive studies are done to date for the promotion of low cost and environment friendly weed based aquaculture in Bangladesh. Therefore, the present study aimed at evaluating the fish growth, yield and economics of polyculture under conventional feed and weed fed ponds.…”