This is a presentation given at the 2009 Phycological Society of Southern Africa conference. The presentation looks at creating a debit credit account for an existing IMTA system in South Africa.

1. INTEGRATED SEAWEED/ABALONE MULTITROPHICINTEGRATED SEAWEED/ABALONE MULTITROPHIC
RECIRCULATING AQUACULTURE (IMTA) IN SOUTH AFRICA:RECIRCULATING AQUACULTURE (IMTA) IN SOUTH AFRICA:
BALANCING THE BALANCE SHEETS, ENVIROMENT ANDBALANCING THE BALANCE SHEETS, ENVIROMENT AND
COMMERCECOMMERCE
Deborah V. Robertson-Andersson1
, Ana M. Nobre2
,
Amir Neori3
, Kishan Sanker6
, Gavin Maneveldt1
, Max
Troell4,5
, Christina Halling5
and John J. Bolton6
1
The Department of Biodiversity and Conservation Biology Department,
University of the Western Cape, Bellville, South Africa.
2
IMAR, Faculty of Sciences and Technology/UNL. Caparica, Portugal.
3
Israel Oceanographic and Limnological Research, National Centre for
Mariculture, Israel.
4
Beijer Institute, Stockholm, Sweden.
5
Department of Systems Ecology, Stockholm University, Stockholm, Sweden.
6
Botany Department, University of Cape Town, South Africa.

2. How to convince an abalone farmer to also farmHow to convince an abalone farmer to also farm
seaweedsseaweeds
Deborah V. Robertson-Andersson1
, Ana M. Nobre2
,
Amir Neori3
, Kishan Sanker6
, Gavin Maneveldt1
, Max
Troell4,5
, Christina Halling5
and John J. Bolton6
1
The Department of Biodiversity and Conservation Biology Department,
University of the Western Cape, Bellville, South Africa.
2
IMAR, Faculty of Sciences and Technology/UNL. Caparica, Portugal.
3
Israel Oceanographic and Limnological Research, National Centre for
Mariculture, Israel.
4
Beijer Institute, Stockholm, Sweden.
5
Department of Systems Ecology, Stockholm University, Stockholm, Sweden.
6
Botany Department, University of Cape Town, South Africa.

3. How do you tell an economist the value of
science?

4. How do you tell an economist the value of
science?
most scientists - seem to take it for granted that scientific
knowledge is valuable for its own sake
value of science must depend exclusively upon the value
of its effects or consequences which somehow affect the
welfare or happiness of sentient beings
draw up a debit and credit account" for science
Lars Bergström Notes on the Value of Science

5. OverviewOverview
How does a phycologist draw up a credit
and debit account?

6. OverviewOverview
How does a phycologist draw up a credit
and debit account?
Ecological-economic assessment by Differential Drivers-
Pressure-State-Impact-Response (DPSIR) approach
Places an economic value on IMTA by looking at the
costs/benefits of implementation of the system
compared to a system without IMTA
The current drivers for integrated seaweed aquaculture
in South Africa.
Socio-economic, environmental and multiplier effects.

7. Differential DPSIRDifferential DPSIR
(i) Drivers - the anthropogenic activities at a given moment in time that
may have an environmental effect and is a socio-
economic component of the DPSIR.
(ii) Pressure - positive or negative direct effects of the Drivers
(iii) State - the condition of the ecosystem at a given moment in time
resulting from both anthropogenic Pressures and natural
factors.
(iv) Impact - the environmental effect of the Pressures, i.e. the
changes on the State of the ecosystem during a given
time period or between two scenarios. An environmental
Impact can be either positive or negative.
(v) Response - management actions and policies that change the
Drivers.

8. 6
8
10
12
14
16
18
20
22
24
26
28
30
A
ug-02
Sep-02
O
ct-02
N
ov-02
Dec-02
Jan-03
Feb-03
M
ar-03
A
pr-03
M
ay-03
Meanwetweight(g)
Mixed diet
Rotation
Fresh Kelp
Fresh Kelp + formulated feed
Formulated feed
Drivers
Lack of and decrease in kelp resource to feed increasing
industry.
High seawater temperatures cause artificial feed to ferment
and bloat abalone.
Mixed diets are known to give better growth
rates.
Potential over-harvesting and decrease in
epiphyte densities on kelp after harvesting.
Limited suitable coastal areas for open ocean
cultivation.
Recirculation – protection from ‘HAB’s’ = 33 %
loss in profits for 1 year.
Rational for IMTARational for IMTA
Effect of diets on
abalone growth rates
Naidoo et al. 2006

9. Effect of harvesting on
regrowth of obligate
epiphytes on kelp
0
0.5
1
1.5
2
2.5
3
3.5
Control harvest
gepiphytes/kgofkelp
Anderson et al. 2006
Drivers
Lack of and decrease in kelp resource to feed increasing
industry.
High seawater temperatures cause artificial feed to ferment
and bloat abalone.
Mixed diets are known to give better growth
rates.
Potential over-harvesting and decrease in
epiphyte densities on kelp after harvesting.
Limited suitable coastal areas for open ocean
cultivation.
Recirculation – protection from ‘HAB’s’ = 33 %
loss in profits for 1 year.
Rational for IMTARational for IMTA

10. Red tide moving towards
abalone intake
Drivers
Lack of and decrease in kelp resource to feed increasing
industry.
High seawater temperatures cause artificial feed to ferment
and bloat abalone.
Mixed diets are known to give better growth
rates.
Potential over-harvesting and decrease in
epiphyte densities on kelp after harvesting.
Limited suitable coastal areas for open ocean
cultivation.
Recirculation – protection from ‘HAB’s’ = 33 %
loss in profits for 1 year.
Rational for IMTARational for IMTA

11. Commercial integrated seaweed abalone system:Commercial integrated seaweed abalone system: 50 % recirculation50 % recirculation
Intake
Seaweed paddle ponds
Sump
Drum filter
Abalone tanks
Header tank
Pump
Seaweed harvest point

12. Feed savings – 120 tons of seaweed produced
Faster abalone growth rates – 6 months less spent on farm
Energy reduction – 350 MWh yr-1
Reduction in concentration and total mass of discharged nutrients
R104 per kg N removed
R48 per kg P removed
Kelp beds not being harvested
R146 per m3
Change in GHG emission
R 200 per ton CO2
Benefits of an IMTA SYSTEM:Benefits of an IMTA SYSTEM:

13. Cost to build to 1 pond in IMTA system
R 51 000
Total cost for 4 ponds
R 0.3 million (once off cost)
Labor for seaweed ponds
R140 000.yr-1
Costs of an IMTA SYSTEM:Costs of an IMTA SYSTEM:

14. Feed savings – R 235 000 yr-1
Faster abalone growth rates – R 720 000 yr-1
Energy reduction - R 56 000 yr-1
Discharged nutrients
44 % decrease in N production
23 % decrease P production
Kelp beds
2.2 ha.yr-1
not being harvested
Change in GHG emission
345 tons.yr-1
ton CO2
Impacts of an IMTA SYSTEM:Impacts of an IMTA SYSTEM:

15. ImpactsImpacts
ENVIRONMENTAL SAVINGS (82 % of the net profit)
The seaweeds take up 12 tons of CO2 y-1
An additional 333 tons of CO2 y-1
are saved by reducing the
electricity usage
92.6 % of N is removed
A 3 % reduction in the harvesting of natural kelp beds
6 % decrease in green house gas emissions by the farm
17.8 % increase in P emissions
NET PROFIT = R 62. 791 million.yr-1

16. SEAWEED PADDLE POND SYSTEM:SEAWEED PADDLE POND SYSTEM:
Costs and savingsCosts and savings
ENVIRONMENTAL SAVINGS:
49 800 Euro yr-1
of avoided costs for N removal;
1 400 Euro yr-1
estimated as the environmental costs for the
increase in the P loads;
300 Euro yr-1
of avoided costs concerning kelp bed
restoration;
4 500 Euro yr-1
of avoided costs of GHG emission offset.
The economic value = 494 200 Euro yr-1
direct benefits to the aquaculture business (estimated as
the change in the aquaculture net profit, 53 200 Euro yr-1
(ZAR 871 000 )) and
indirect environmental benefits (estimated as the value of
the externalities, 541 000 Euro yr-1
(ZAR 3839 000))
ZAR 9.495 = € 1*
*
FMI 2007 and includes purchasing power parity

17. Conclusion:Conclusion:
Nick Loubser I & J General manager
“The actual financial benefits are difficult to
determine but in ball park terms we calculate
that the seaweed contributes at least R500 000
a year to the farm in feed cost savings alone.”
Our calculations show a savings of R871 000
per year.
McVeigh, S. J.. 2007. First Green Filters for aqauculture. Fishing industry news. June 2007. pg 16 - 17.

18. THANK YOUTHANK YOU
ACKNOWLEDGEMENTS
I would like to extend special thanks to the following
organizations without whose help this project would
have
been impossible:
Swedish and South African Collaborative Program
I & J Mariculture farm
N R F
SANCOR Prestige Student travel grant