AquaPark Panabo Stakeholders meeting interim results
AquaPark – Norad funded projectPlanning and management of
aquaculture parks for sustainable development of cage farms in the
Philippines
AquaPark Panabo Stakeholders meeting interim results
TROPOMOD modelling of aquaculture zones
Chris CromeyMap and Marine Ltd
Out put from AquaPark
Aquapark Project Partners–Bureau of Fisheries and Aquatic Resources–Akvaplan-niva AS–Map and Marine Ltd
AquaPark Panabo Stakeholders meeting interim results
AquaPark Panabo Stakeholders meeting interim results
Model assumptions
AquaPark Panabo Stakeholders meeting interim results
Simulation
TROPOMOD modelling approach
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
Maintain enough spacing between cage rows so that remediation of sediments can take place – impact should be LOW between rows in each zone
Maintain enough space between cage rows to prevent reduction of currents by high aggregation of cages
Zone colour
TROPOMOD modelling Approach
Encourage careful feeding, so that there is less waste feed and less wastage of money
Encourage better quality feed: Feed digestibility is increased Less feed is needed Better quality feed also breaks up less, so more goes to growth
Distance between parks
Prevent overlap of impact by predicting the extent of the zones – e.g. 600 m between zones for this site
0 200 400 600 800Scale (m )
TROPOMOD modelling Approach
AquaPark Panabo Stakeholders meeting interim results
Panabo sediment trap model validation studies
Objective – to measure flux (deposition) of waste feed and faeces under cages and compare with model predictions – this helps us to verify the model predictions and test different scenarios
Sediment traps were deployed in Spring 2010 survey:
One transect for Milkfish (0 metres from cage, 10 m and reference)
One for Grouper (0 metres from cage, 10 m and reference)
Chris Cromey – EMMA2 project modeller using data from Akvaplan and BFAR survey teams
AquaPark Panabo Stakeholders meeting interim results
Sediment trap model validation study – method for deploying sediment traps
75 cm
H:D = 5:1 ratio
Sea bed
1. Deploy traps
2. Retrieve, filter, dry solids
3. Calculate observed flux
(total waste feed and faeces in traps = grams per m2 bed per day)
4. Compare with TROPOMOD model
Cage
Current
AquaPark Panabo Stakeholders meeting interim results
TROPOMOD model – method• Cage positions were obtained from recent
Google Earth image
• Feed ration for cages obtained from AquaPark production survey
• Production survey results summarised to include modelling of different stages of Milkfish monoculture (starter, grower and finisher), as well as other species (Milkfish-Siganid polyculture, Grouper, etc.)
AquaPark Panabo Stakeholders meeting interim results
TROPOMOD model – method• Settling velocity of feed obtained from EMMA2
project pellet break up experiments and PHILMINAQ project experiments
• Settling velocity of Milkfish faeces from PHILMINQ project
• Depth obtained from BFAR surveys
• Uneaten feed (27%), digestibiity (49%) and water content (9%) – data from PHILMINAQ project
AquaPark Panabo Stakeholders meeting interim results
TROPOMOD model – method• Current meter data from BFAR surveys used
• TROPOMOD set up with information and used to predict flux of waste feed and faeces (grams per m2 bed per day) for Panabo Aquaculture park
AquaPark Panabo Stakeholders meeting interim results
TROPOMOD predicted flux (deposition) of waste feed and faeces for Panabo
The colours show different amounts of flux
Sediment trap transects:
Grouper (traps are in 6 m depth)
Milkfish transect (traps are in 27 m depth)Reference traps
Model predictions
Higher flux and predicted impact in the inshore areas
AquaPark Panabo Stakeholders meeting interim results
Milkfish sediment trap transect
Problem – cage locations taken from recent Google Earth image and trap locations taken from survey do not match as station M0m should be at cage edge, and M10m should be 10 m from cage
Solution – make minor adjustments to cage/station positions in model so they match
Two stations (three traps at each)
Feed ration = 50 kg per cage per day
AquaPark Panabo Stakeholders meeting interim results
Grouper sediment trap transect
These cages are in shallower water and feed ration is 10 kg per cage per day, which is less than for Milkfish monoculture
Two stations (three traps at each)
AquaPark Panabo Stakeholders meeting interim results
Milkfish – comparison of observed flux and predicted
For both the 0 m and 10 m stations, the model slightly over-predicted flux
Note the variation between traps at the same station
Traps are adjusted for background sedimentation
AquaPark Panabo Stakeholders meeting interim results
Grouper – comparison of observed flux and predicted
Model predictions of flux were satisfactory for Grouper
Note the variation between traps at the same station
Traps are adjusted for background sedimentation
AquaPark Panabo Stakeholders meeting interim results
All sediment trap data collected by Cromey et al. at SAMS
Panabo measurements were less than 20 g m-2 d-1, which is at the low end of measurements taken
AquaPark Panabo Stakeholders meeting interim results
Conclusions and next steps
TROPOMOD predicted flux satisfactorily for Grouper, but over-predicted for Milkfish – we will look at this more carefully after refinements
Modelling of the whole park showed higher impact in the inshore areas, where the depth is shallower and dispersion is lower
Modelling the whole park requires care, as cage locations and feed inputs vary widely across the park depending on the source of data – for management scenarios, some randomness can be introduced to account for this
AquaPark Panabo Stakeholders meeting interim results
Conclusions and next steps
Next steps are to model the park by organising species into zones
Identify areas for oysters and seaweed
Further refinements of the modelling are needed, incorporating as much information from the Spring 2010 surveys as possible