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optimization of the stocking density and size of red tilapia in intensive polyculture of white shrimp litopenaeus vannam

2011/9/13. 2. . Aquaculture CRSPUSAID. Travel funding for this presentation was provided by Aquaculture Collaborative Research Support Program. The Aquaculture CRSP is funded in part by United States Agency for International Development (USAID) Grant No. LAG-G-00-96-90015-00 and by participating institutions. The opinions expressed herein are those of the authors and do not necessarily reflect the views of the US Agency for International Development. .

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optimization of the stocking density and size of red tilapia in intensive polyculture of white shrimp litopenaeus vannam

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    1. 9/13/2011 1 OPTIMIZATION OF THE STOCKING DENSITY AND SIZE OF RED TILAPIA IN INTENSIVE POLYCULTURE OF WHITE SHRIMP Litopenaeus vannamei AND RED TILAPIA Oreochromis spp. Yuan Derun1, Yang Yi2, Amararatne Yakupitiyage1 1. AARM, SERD, AIT 2. SHFU

    2. 2011/9/13 2

    3. 9/13/2011 3 Introduction Shrimp culture has been one of the most active and important sector in aquaculture in past two to three decades. Production increased from 87,831 metric tons (MT) in 1981 to about 2 million MT in 2005 (FAO, 2006).

    4. 9/13/2011 4 Introduction Despite the benefits, it has long been associated with environmental issues (Pruder, 1992; Phillips et al., 1993; Lin, 1995; Boyd and Clay, 1998; Fast and Menasveta, 2000; Lin, 2000).

    5. 9/13/2011 5 Introduction

    6. 9/13/2011 6 Introduction – the Problem Negative environmental impacts Economic loss of costly nutrients, thereby reducing farm profitability (Burford et al., 2001).

    7. 9/13/2011 7 Introduction Need to develop culture technology/systems with increased waste assimilating capacity: to transfer the excessive nutrients into harvestable aquatic products and to avoid uncontrolled effluent discharge.

    8. 9/13/2011 8 Introduction Polyculture: Centuries old (Lin, 1969; Lin, 1982); Worldwide practice (Hepher and Milstein, 1989). The rationale: complementary to each other, more efficient utilization of food available in the pond. A possible solution/alternative?

    9. 9/13/2011 9 Introduction Shrimp polyculture: old practice Been cultured with fish (milk fish, mullet, tilapias, other shrimp, Glacilaria seaweed, bivalves etc. Purposes: To increase overall production To earn extra income To control water quality, and To spread culture risks.

    10. 9/13/2011 10 Introduction The researches and practices were however mainly based on extensive and semi-intensive systems. Few attempts have been made to polyculture shrimp intensively.

    11. 9/13/2011 11 Introduction Akiyama and Anggawati (1999) observed two cycles of shrimp production in ponds in Ecuador and found that yields of shrimp increased when red tilapia (Oreochromis spp.) were stocked into existing shrimp ponds. It was believed that red tilapia assisted shrimp performance by improving and stabilizing the water quality, by foraging and cleaning the pond bottom and by having a probiotic type effect in the pond environment.

    12. 9/13/2011 12 Introduction A preliminary study of intensive shrimp/tilapia polyculture conducted by Yang Yi et al. (2002) in Thailand demonstrated positive specific interaction and mutual benefit between two co-cultured species. P. monodon in such an intensive polyculture system seemed to have the similar survival rates and FCR to those in monoculture controls.

    13. 9/13/2011 13 Introduction However, questions still remain: how shrimp would respond to the interaction of tilapia socking density and size at what stoking density and size tilapia should best benefit shrimp production. Furthermore, few studies done on polyculture aspect of L. vannamei, - the dominant species in shrimp culture worldwide.

    14. 9/13/2011 14 Introduction The objective was: To assess the effects of addition of red tilapia Oreochromis spp. at different densities and sizes on: shrimp growth, water quality and nutrient recovery in intensive culture of white shrimp Litopenaeus vannamei.

    15. 9/13/2011 15 MATERIALS AND METHODS

    16. 9/13/2011 16 MATERIALS AND METHODS

    17. 9/13/2011 17 RESULTS: Shrimp growth performances

    18. 9/13/2011 18 RESULTS: Growth performances of tilapia and combined

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    24. 9/13/2011 24 RESULTS N Recovery

    25. 9/13/2011 25 RESULTS P Recovery

    26. 9/13/2011 26 CONCLUSIVE SUMMARY No significant reduction of shrimp production occurred in the polyculture tanks with red tilapia of 13.8 g stocked at 0.4 to 0.8 fish m-2, or with red tilapia of 41.9 g stocked at 0.4 fish m-2. Synergistic effect in terms of improved shrimp survival rate happened in shrimp tanks with red tilapia at 0.4 fish m-2 with the stocking size at 13.8 g. The effects nearly diminished in the treatments with larger tilapia or at higher socking density as compared with the control.

    27. 9/13/2011 27 CONCLUSIVE SUMMARY Increasing tilapia stocking density from 0.4 to 1.2 fish m-2 and stocking size from 13.8 to 41.9 g in polyculture negatively affected shrimp production performances, but remarkably increased overall nutrient utilization and total production. The study demonstrated that white shrimp could be cultured intensively with red tilapia in a polyculture system. With proper stocking size and density of red tilapia, the polyculture system could achieve a similar shrimp production level comparable to that of monoculture without extra feed inputs, and produce tilapia as an additional crop.

    28. 9/13/2011 28 Thank You !!!

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