Score test in robust M-procedure

A score type test based on the M-estimation method for a linear regression model is more reliable than the parametric based-test under mild departures from model assumptions, or when dataset has outliers. An R-function is developed for the score M-test, and applied to two real datasets to illustrate the procedure. The asymptotic power function of the M-test under a sequence of (contiguous) local alternatives is derived. Through computation of power function from simulated data, the M-test is compared with its alternatives, the Student's $t$ and Wilcoxon's rank tests. Graphical illustration of the asymptotic power of the M-test is provided for randomly generated data from the normal, Laplace, Cauchy, and logistic distributions

Suitability of Duckweed (Lemna minor) as Feed for Fish in Polyculture System

In the present study, we conducted an experiment to evaluate the effects of duckweed (Lemna minor) as feed on fish production in polyculture. The experiment had 2 treatments where in treatment 1 (T1) ponds were supplied with duckweed as feed and in treatment 2 (T2) ponds were kept as control (without supply of duckweed). Average survival rates in T1 and T2 were 90 and 89%, respectively. The specific growth rates (SGR) were higher in T1. Calculated net production in T1 was 6.25 tons ha.-1 yr.-1 and in T2 was 2.84 tons ha.-1 yr.-1. The ranges of physico-chemical parameters analyzed were within the productive limit and more or less similar in all the ponds under both treatments during the experimental period. There were 24 genera of phytoplankton under 5 major groups and 10 genera of zooplankton under 3 major groups found in the experimental ponds. The net production in T1 was significantly higher than that of T2 indicated the use of duckweed as feed for fishes is economically sustainable in polyculture. DOI: http://dx.doi.org/10.3329/ijarit.v2i1.13994 Int. J. Agril. Res. Innov. & Tech. 2 (1): 42-46, June, 201

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

Plankton is an important food item of fishes and indicator for the productivity of a water body. The present study was conducted to evaluate the effects of bottom soil textural conditions on abundance of plankton in aquaculture pond. The experiment was carried out using three treatments, i.e., ponds bottom with sandy loam (T1), with loam (T2) and with clay loam (T3). The ranges of water quality parameters analyzed were suitable for the growth of plankton during the experimental period. Similarly, chemical properties of soil were also within suitable ranges and every parameter showed higher ranges in T2. A total 20 genera of phytoplankton were recorded belonged to Chlorophyceae (7), Cyanophyceae (5), Bacillariophyceae (5), Euglenophyceae (2) and Dinophyceae (1). On the other hand, total 13 genera of zooplankton were recorded belonged to Crustacea (7) and Rotifera (6). The highest ranges of phytoplankton and zooplankton densities were found in T2 where low to mediumtype bloom was observed during the study period. Consequently, the mean abundance of plankton (phytoplankton and zooplankton) density was significantly highest in T2. The highest abundance of plankton in the T2 indicated that pond bottom with loamy soil is suitable for the growth and production of plankton in aquaculture ponds. DOI: http://dx.doi.org/10.3329/ijarit.v2i1.14006 Int. J. Agril. Res. Innov. & Tech. 2 (1): 56-61, June, 201

Histopathological and environmental effects of the insecticide, sumithion on the fish, tilapia (Oreochromis niloticus) in pond condition

The present research work was conducted to evaluate the effects of organophosphate insecticide, sumithion on water quality parameters, density of plankton population and histological changes of kidney and liver of the fish, tilapia (Oreochromis niloticus) in aquaculture ponds during July to December 2016. The experiment was conducted with four treatments, each with two replications. Treatment T0 was used as control (no sumithion) and other three treatments with 0.025 ppm (T1), 0.050 ppm (T2) and 0.100 ppm sumithion (T3). The water quality parameters such as dissolved oxygen, free carbon dioxide, pH, total alkalinity, NO3-N and PO4-P fluctuated significantly under four treatments during the experimental period but they were not affected by sumithion application. The phytoplankton densities (×105 cells L-1) was not affected by sumithion. Six genera of phytoplankton populations were found in the experimental ponds. On the other hand, zooplankton population densities (×103 cells L-1) were significantly reduced with increasing doses of sumithion (T2 and T3) in comparison with that of control (T0). Histological changes of kidney were observed after application of sumithion. The renal corpuscle, collecting duct, hematopoietic cells and other cells of the kidney in control (T0) were normal and systematically arranged. Abnormal collecting duct, Intra-cellular space, degenerated renal corpuscle, irregular shaped blood vessel, ruptured membrane large vacuole and necrosis were found in T1, T2 and T3.Normal structure of liver cells such as hepato-pancreas, hepatic cell and blood vessel were observed in T0 (control). Sumithion exposed liver sections showed rupturedhepato-pancreas, necrosis, hemorrhage, intra-cellular space, degenerated hepatopancreas and large vacuole were found in T1, T2 and T3. Therefore, it reveals that sumithion has adverse effects on kidney and liver of the test fish. So, sumithion should not be used indiscriminately in agriculture and aquaculture practices. It may be concluded from the research finding that dissolved oxygen, free carbon dioxide, pH, total alkalinity, PO4-P, NO3-N, phytoplankton and zooplankton values under treatment, T0, are significantly different from treatments T1, T2, and T3 in most cases. Int. J. Agril. Res. Innov. & Tech. 9 (1): 84-95, June, 201

Control of euglenophyte bloom and fish production enhancement using duckweed and lime

Euglenophyte bloom is a common problem in most of the aquaculture ponds in Bangladesh. In the present study we conducted an experiment to control euglenophyte bloom for getting better fish production using duckweed (Lemna minor) and lime. The experiment was carried out using four treatments, i.e., ponds were supplied with duckweed (T1), lime treatment (T2), both duckweed and lime (T3) and without supply of duckweed and lime (T4). Rohu, catla, mrigal, silver carp and silver barb were stocked and their gut contents were analyzed monthly. The ranges of water quality parameters were analyzed within the productive limit during the experimental period. The mean abundance of euglenophyte was significantly highest in T4 (17.62 ± 1.97 × 104 cells/L), followed by T2 (2.96 ± 0.20 × 104 cells/L), T1 (1.94 ± 0.35 × 104 cells/L) and T3 (1.53 ± 0.42 × 104 cells/L). Gut content analysis revealed that considerable amount of euglenophyte were consumed by silver carp and silver barb, but not preferred by rohu, catla and mrigal. The gross yields of fish were 2133.37, 1967.76, 2816.52 and 1725.62 kg/ha/5 months in T1, T2, T3 and T4, respectively. The highest fish production in T3 and lowest fish production in T4 indicated the use of duckweed and lime is economically sustainable for controlling euglenophytes bloom, maintaining water quality and getting higher fish production

Culture of Chlorella ellipsoidea in different culture media

An experiment of algal culture was conducted in natural light and temperature conditions at a balcony of a room at the 2nd floor of Fisheries Faculty Building facing the north. The experiment was done to evaluate the growth of Chlorella ellipsoidea in four different media, viz, medium I (inorganic), medium II (organic, whole pulse powder extract), medium III (organic, whole lentil powder extract) and medium IV (organic, whole gram powder extract) under natural environment conditions during January-June, 2015. Growth rates of the algal species in four different media were found not significantly different. The alga, C. ellipsoidea attained maximum cell density of 28.89×106 cell ml-1 in the 15th day in medium I, of 30.69×106 cell ml-1 in the 13th day in medium II, of 26.18×106 cell ml-1 in the 15th day in medium III and of 21.12×106 cell ml-1 in the 13th day in medium IV. The ranges of air temperature, water temperature and light intensity were 21°C to 38°C, 23°C to 36°C and 2.28×103to 9.60×103 Lux respectively during the culture period. The average sunshine period was 5.87±2.82 hrs. Total alkalinity, free CO2, pH , NO3-N and PO4-P of algal culture media I, II, III and IV were 128, 540, 554 and 322 mgL-1; 32, 162, 102, 70 mgL-1; 7.4, 8, 7.9 and 7.9; 180, 36.6, 62.4 and 150 mgL-1, and 25.2, 48.2, 42.4 and 45.6 mgL-1, respectively. According to ANOVA of cell densities of cultures of C. ellipsoidea under treatments are not significantly different (F=1.441077). It is clear that differences between them are not significant i.e. mean algal cell densities are more or less same as differences between treatments are less than 20%.Int. J. Agril. Res. Innov. & Tech. 7 (1): 51-57, June, 201

Short communication: Culture of Chlorella ellipsoidea in different inexpensive medium and used as food for production of rotifer, Brachionus calyciflorus

Rotifers are multicellular animals with body cavities that are partially lined by mesoderm. These organisms are valuable live food for larval fish and crustacean culture. Several characteristics of rotifers, including their nutritional quality, body size and relatively slow motility have contributed to their usefulness as good prey for active larvae. In general, rotifers have both nutrient content and a high rate of daily production. ... In the present study, we cultured Chlorella ellipsoidea in different media and used as food in powdered and fresh live form along with Backer’s yeast to mass production of rotifers

Effect of use of duckweed powder as a fish feed on monoculture of silver carp (Hypophthalmichthys molitrix)

An experiment on the use of duckweed powder as a fish feed on monoculture of silver carp (Hypophthalmichthys molitrix) was conducted in 6 ponds for a period of 75 days. The area of the each pond was one decimal. The experiment was carried out under two treatments, each with 3 replications. A combination of duckweed powder and rice bran at the ratio of 3:1 was supplied at the rate of 4% of total body weight in the ponds under treatment-I. On the other hand, the ponds under treatment-II were without supplying of feed. Each of the ponds under both treatments were stocked with 45 fingerlings of silver carp (H. molitrix). The average initial length and weight of the fingerlings were 14.60 cm and 33.48 g, respectively. The ponds were fertilized fortnightly with poultry droppings at the rate of 2 kg, urea 60 g and TSP 90 g decimal-1. During the experimental period the ranges of physico-chemical parameters viz. water depth (0.82 to 0.90 m), water temperature (17.80 to 26.7 °C), air temperature (19.11 to 28.29 °C), transparency (28.00 to 34.00 cm), dissolved oxygen (6.70 to 8.20 mg L-1), pH (6.70 to 8.00), total alkalinity (170 to 210 mg L-1), free CO2 (0.0 to 3.50 mg L-1), phosphate-phosphorus (1.2 to 2.9 mg L-1), and nitrate-nitrogen (3.1 to 4.5 mg L-1) were within the productive limit and more or less similar in all the ponds under treatments I and II. There were 25 genera of phytoplankton under four major groups and 10 genera of zooplankton under three major groups in the experimental ponds. Mean survival rates under treatment-I and treatment-II were 97.78% and 95.56%, respectively. The specific growth rates (SGR % per day) of the fish found under treatment-I and treatment-II were 0.98% and 0.49%. The calculated net production of the ponds under treatment-I was 1.87 ton ha-1 yr-1 and that of the ponds under treatment-II, was 0.74 ton ha-1 yr-1. By 't' test, it was found that the net fish production of treatment-I was significantly (p<0.01) higher than that of treatment-II, and cost return relationship was found that the net profit of treatment-I and treatment-II were more or less similar. Finally, it can be concluded that duckweed powder as an ingredient of fish feed had significant impacts on production of silver carp, which do not consume duckweed as fresh and raw condition. Thus, duckweed powder can be used as feed for most fishes. Int. J. Agril. Res. Innov. & Tech. 9 (1): 73-83, June, 201