aqua park environmental impacts of cage culture


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Environmental impact surveys for aquaculture parks in the Philippines. The spatial extent and level of local environmental impact caused by a fish farm is determined by natural conditions such as bottom topography, sediments and currents, in combination with the size of fish production and operational practices. A major factor in preserving environmental quality is an optimal location and operation of the farm, conforming to the existing environmental conditions.

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  • If you measure of model the dissolved nutrients in the water around a fish farm you will see a trail of nutrients coming from the farm and taken away by currents gradually becoming more diluted.
  • aqua park environmental impacts of cage culture

    1. 1. Planning and management of aquaculture parks for sustainable development of cage farms in the Philippines Regino R. Regpala Environmental impact
    2. 2. Nutrient balance
    3. 3. Inputs, uptake and outputs Less than30 % of inputs are retained by the fish. The remainder go into the environment
    4. 4. Impact on the sediments • Sustainable levels – slight build up of organic layer on the seabed • Unsustainable level - Build up of thick organic layer on the sea bed • Smothering of seagrass • Smothering of corals AquaPark Mid-term meeting - interim results
    5. 5. Phosphorus plume from fish cages
    6. 6. Impact on water column • Increasing nutrient concentration in the water • Sustainable levels lead to algae production – zooplankton production – increased wild fishery production • Unsustainable levels leads to high algae production – algal bloom – algae die off – low/no oxygen – fish kill AquaPark Mid-term meeting - interim results
    7. 7. Comparison of impacts Mariculture Park Biomass (mT) Cage size (m3) Stocking (pcs) Survival rate (%) Culture period (mos.) Feeding ratio (%) Monthly growth rate (%) FCR Ignition Loss 550oC (%) pH Dark layer (cm) Panabo 3.28 400 15,000 96.9 4.3 4.09 228.2 2.17 7.82 7.8 10.8 Sual 43.9 2,544 108,000 81.3 9 1.71 77.8 2.3 9.94 7.8 15.09
    8. 8. Environmental survey - Sual
    9. 9. Natural sediment Heavily impacted sediment
    10. 10. Corer 800 m from cage no black layer
    11. 11. Corer 500 m from cage 5 cm black layer
    12. 12. Corer 87 m from cage 13 cm black layer
    13. 13. Corer at cage 20 cm black layer
    14. 14. Modelling environmental impact 3 important aspects: 1.How severe is the impact – what is the maximum impact underneath cages? 2.How far to the boundary of the impact? (Allowable Zone of Effect) 3.How can husbandry practices be optimised to use the zone most productively? Objectives Predict if impact is SEVERE underneath cages as shown by this deposition footprint Zone colour Predict distance to boundary of MODERATE impact Zone colour Edge of Park
    15. 15. Environmental impact Limited local Impact Cumulative impact
    16. 16. Cumulative impact • Increasing disease problems • Lower survival • Poor food conversion rate Often blame • Poor fry quality • Poor food quality But the problem is usually high environmental impact WAS Istanbul - Competing Claims
    17. 17. Monitoring Monitoring of the MP is necessary • To check the level of impact on the environment • Check if the impact is getting worse, staying the same or getting better • Early warning of future problems • Oil spill contingency plan WAS Istanbul - Competing Claims