Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Optimum Harvest for Sustainable Yield of Fish Live Food Tubificid Worms

Anwar Hossain
Department of Fisheries, University of Dhaka, Dhaka‐1000, Bangladesh

Mohammad Shamsur Rahman
Department of Fisheries, University of Dhaka, Dhaka‐1000, Bangladesh

Mahmud Hasan
Department of Fisheries, University of Dhaka, Dhaka‐1000, Bangladesh

Abstract/ Executive Summary:

The Optimum harvest suitable for sustainable yield of tubificid worms without affecting the future yield for a period of 60 days was determined. The media ingredients used to culture the worms were 20% wheat bran, 30% soybean meal, 20% mustard oil cake, 20% cow dung and 10% sand. A harvest level of 50 mg/cm² (maximum yield; 518.93 ± 14.36 mg/cm2) at ten days interval starting from 30 days of worms’ inoculation was found suitable for sustainable yield in the later sampling durations. Results of this study have implications in increasing fish yield by producing reliable and sustainable yield of fish live foods tubificid worms.

Keywords: Tubificid worms, Live food, Optimum harvest, Sustainable yield

Location: Bangladesh Agricultural University, Mymensingh

Start Date: 00-04-2009

End Date: 00-06-2009

Program Area: Animal Health and Management

Commodity: Aquatic animal

Objectives:

To determining the suitable harvest level for sustainable yield of tubificid worms.

Methodology:

Tubificid worms were collected from different places of Mymensingh and cleaned by water flow and held in a flow?through?system. The worms were conditioned for 24 hours before inoculation into the culture culverts. The experiment was conducted between April and June, 2009 for 60 days. The worms were cultured in indoor cemented culverts (160 × 25 × 10 cm³) system to protect them from rain and sunlight or any other natural hazards. At the beginning of the experiment, the culverts were washed and cleaned with fresh water. The culverts were connected with a flow?through?system in which subsurface well water was used. Each culvert was given continuous water spray by using a horizontal porous PVC pipe (180 cm long and 1 cm² diameter). The experiment was conducted in the Department of Fisheries Biology and Genetics, Bangladesh Agricultural University, Mymensingh. A 4 × 4 factorial design was employed in triplicates to study the effects of four different harvest levels (30, 40, 50 and 60 mg/cm²) and four sampling durations (30, 40, 50 and 60 day) for the sustainable yield of tubificid worms. The ingredients wheat bran (20%), soybean meal (30%), mustard oil cake (20%), cow?dung (20%) and 10% sand were used. The ingredients were mixed with water to get wet for a period of seven days for enhanced decomposition. Successive mixing was done twice a day for better mineralization. Culture media were placed and water flow was adjusted 24 hours before inoculation of worms to the culverts. The collected tubificid worms were inoculated at the rate of 2.5 mg/cm² (i.e. 10 cg/culvert). They were spread over the media homogeneously as much as possible in each culvert. Continuous water flow was maintained which was able to keep the dissolved oxygen in suitable range (4?6 mg/cm²). The water flow rate was maintained by adjustment stop cork of PVC pipes. The periodic supply of culture media was done after 10 days of worms’ inoculation. The prepared media were introduced at the rate of 250 mg/cm² in respective culverts once in every 10 days at 10.00 a.m. before sampling. Total quantity of media was spread through out the culverts. At that time, water flow was stopped for a while. Water flow rate (L/min) was measured once in ten days. Water temperature (ºC) of the culture culverts and dissolved oxygen (mg/l) was detected with the help of a portable dissolved oxygen meter (Jenway, Model No. 9070, UK) before sampling at 10.00 a.m. once in every 10 days. Samples were drawn at 30, 40, 50 and 60 day of 60 days culture duration. Samples were collected by using a sampler (4.4 × 4.4 cm²) with water and media from five randomly selected places of each culvert. The worms were cleared by flowing water and separated with a pair of forceps and dropper from the unwanted particles. Cleaned tubificid worms were dried with blotting paper and weighed by Matler electric balance (Switzerland) graduated in 0.000 g. Data were analyzed by using ANOVA followed by Tukey’s HSD post hoc for multiple comparisons. Data have been presented as mean ± SEM and analyzed by using the statistical software SPSS version 11.5 with the level of significance at p < 0.05.

Source of Information: Dhaka Univ. J. Biol. Sci. 20(1): 57‐63, 2011 (January)[http://www.banglajol.info/index.php/DUJBS/article/view/8838/6554]

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

Highest yield was found for the overall effects of different harvest levels when the harvest level was 50 mg/cm² at a 60?day?sampling. suitability of the quantity to be harvested to maintain the post?harvest population that could be sustainable for future harvest. A little bit higher yield (852.43 mg/cm²) has been found(10) than the yield of present study by harvesting 30 mg/cm² with same harvest interval but they needed 2.67?folds longer duration which of course makes the study impractical and economically nonviable. Because cost associated with additional culture duration over 100 days has resulted only 134 mg/cm² yield which clearly demonstrates the unsuitability of this harvest level and also culture duration. the harvest levels 30 mg/cm² and 40 mg/cm² were under?harvested because their initial standing biomass was gradually increased and then reached the carrying capacity of the culture system. And just after exceeding the level of carrying capacity of the culture system, the production of both treatments dropped because of sudden death of a considerable number of tubificid worms. The death might have occurred due to oxygen depletion (2.1 mg/l). The tubificid population usually distorted after the introduction of the media when the rate of decomposition of media was comparatively high needing enormous amount of oxygen. On the other hand, the harvest levels 60 mg/cm² was over harvested because the remaining biomass decreased over the harvesting periods. Across the four treatments tested, the harvest levels 50 mg/cm² showed more sustainable condition than others. The remaining biomass was not affected in 50 mg/cm² harvest level. The result has shown that 50 mg/cm² can be considered as the optimal and balanced harvest level to get the sustainable production of tubificid worms in the future harvest.

Knowledge Management: Journal