ICOMSA, 2014 STUDY ON CONCOMITANT CULTURE OF MUD CRAB Scylla sp IN FIBRE GLASS TANK AND FLOATING PLASTIC CAGES: AN INTEGRATED-MULTI LAYERED AQUACULTURE APPROACH OF MUD CRAB AND SEA WEED (ULVA) 1Md. Latiful Islam, 1Md. Arif Chowdhury, 2Roshada Hashim and 1,2Khairun Yahya 1. Centre for Marine and Coastal Studies (CEMACS) University Sains Malaysia, Penang Malaysia 2. School of Biological Sciences, USM, Penang 1

Saving of productive land is world wide concern; ICOMSA, 2014 Background: Saving of productive land is world wide concern; Integrated agro-aquaculture and/or intercropping to boost up per unit production; Polyculture, technique for utilization of all niche to enhancement of yield; Semi-intensive aquaculture for booming production through vertical expansion; Integrated rice-fish-shrimp Agro-intercropping Theme of polyculture 2 Semi-intensive shrimp pond

Is semi-intensive culture technique applicable for mud crab grow out? ICOMSA, 2014 Background (cont’d): Is semi-intensive culture technique applicable for mud crab grow out? Many researcher mentioned 0.5 to 1/m2 stocking density for mud crab; Is it sufficient enough for livelihood of marginal crab farmers? Who possess only 1 to 10 decimal pond; How can per unit production be boosted up for mud crab? Marginal farmer with small pond

Use of multi layer for crab could be an option; ICOMSA, 2014 Background (cont’d): Use of multi layer for crab could be an option; Integration of symbiotic species could be helpful for production increment’ With this view study was designed for concomitant culture of mud crab in plastic boxes and tank bottom along with integration of sea weed (Ulva) Experimental tanks Floating plastic box

Methodology: Experimental design Treatment Replication ICOMSA, 2014 Methodology: Experimental design Treatment Replication Treatment details Stocking density T1 3 Mud crab grown in tank bottom, integration with sea weed T2 Mud crab in tank bottom + mud crab in floating boxes, integration with sea weed 2/m2 1/box 2/m2 * Area of each box: 30cm×25cm×15cm; *area covered: about 40% by 40 box

Methodology (Cont’d): ICOMSA, 2014 Methodology (Cont’d): Tank preparation: 1m2 sand bedX5 inch thick; Setting of Aeration, inlet and outlet; Culture duration for seaweed: 7 months Culture duration, crab: 5 months (from C3) * First month as community basis; Feeding: trash fish, @ 8-10% bw Growth monitoring: monthly (Tw; Cl; Cw) Sea weed growth monitoring: monthly (by floating box and squire frame); Water quality monitoring: monthly

Result: Water quality variables: ICOMSA, 2014 Result: Water quality variables: Variables T1 T2 Temperature (0C) 28.0-34.6 28.5-33.5 Salinity (ppt) 22-30 22.-29 DO (mg/l) 5.2-8.6 4.8-8.2 pH 7.8-8.8 7.7-8.9 TSS (mg/l) 0.03-0.05 0.05-0.08 * Remarkable is the very low TSS due to absorption by sea weed

ICOMSA, 2014 Result (cont’d): Monthly body weight increment under different treatment 1st month crabs were reared in community basis; after assigning to treatments (31.30g), growth increment in boxes was found suddenly slow down; in free areas, size variation was higher, while in boxes it was found less.

ICOMSA, 2014 Result (cont’d): Details in survival and production under different treatment Particulars Treatment-1 (T1) Treatment-2 (free) Treatment-2 (box) Body weight (g) 249.83 ±21.06a (228.50-270.60) 251.90±29.93a (220.80-280.90) 204.27±5.91b (198.60-210.40) Survival (%) 54.33±10.26b (43.00-63.00) 57.33±7.51b (50.00-65.00) 95.00±5.00a (90.00-100.00) Production (kg/tank) 1.90±0.32b (1.62-2.25) 2.03±0.42b (1.55-2.29) 7.77±0.63a (7.15-8.42) Appendages lost (%) 21.30±4.24 (16.00-24.00) 20.50±5.56 (18.00-24.00) 0.00 Sea weed (kg/tank) 28.33±5.13a (24-34) 28.0±7.47a (36.5-22.5) --

Due to incorporate of floating box in T2- ICOMSA, 2014 Due to incorporate of floating box in T2- added production of 300% to the treatment production increment was 315% over T1

Adequate feeding is therefore pre-requisite; ICOMSA, 2014 Limitations: Adequate feeding is therefore pre-requisite; At hot period, shed on the boxes may save from heat; Conclusion: This study showed way to boost up mud crab production through concomitant culture in free pond/tank area and floating boxes. Sea weed play a role to clean up water and proving hiding place during molting. Sea weed also provided additional crop; More symbiotic species could be incorporated to enhance production; which require further study.

Acknowledgement: Bangladesh Fisheries Research Institute (BFRI) for ICOMSA, 2014 Acknowledgement: Bangladesh Fisheries Research Institute (BFRI) for nomination and granting study leave. Bangladesh Agricultural Research Council (BARC) for financing under NATP-phase-1 Project. Supported by Delivering Excellence Grant 1002/PPANTAI/910331 Center for Marine and Coastal Studies (CEMACS) for available facilities with friendly environment.

ICOMSA, 2014 Sustainable production for tomorrow THANKS TO ALL