aqua park environmental impacts of cage culture
DESCRIPTION
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.TRANSCRIPT
Environmental impact
Planning and management of aquaculture parks for sustainable development of cage farms in the
Philippines
Regino R. Regpala
www.aqua-park.asia
Nutrient balance
Inputs, uptake and outputs
Less than30 % of inputs are retained by the fish. The remainder go into the environment
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
Phosphorus plume from fish cages
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
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
Environmental survey - Sual
Natural sediment Heavily impacted sediment
Corer 800 m from cage no black layer
Corer 500 m from cage 5 cm black layer
Corer 87 m from cage 13 cm black layer
Corer at cage 20 cm black layer
Modelling environmental impact3 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 colourEdge of Park
Environmental impact
Limited local Impact
Cumulative impact
Cumulative impact
WAS Istanbul - Competing Claims
• 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
Monitoring
WAS Istanbul - Competing Claims
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