THE EVOLUTION OF INTEGRATED THE EVOLUTION OF INTEGRATED SEAWEEDSEAWEEDCULTIVATION IN TEMPERATE SOUTHERNCULTIVATION IN TEMPERATE SOUTHERNAFRICAAFRICA

THE EVOLUTION OF INTEGRATED THE EVOLUTION OF INTEGRATED SEAWEEDSEAWEEDCULTIVATION IN TEMPERATE SOUTHERNCULTIVATION IN TEMPERATE SOUTHERNAFRICAAFRICA

Robertson-Andersson Deborah1,5; J. J. Bolton1, M. Troell2,3, R. J. Anderson4, G. Maneveldt5, C.

Halling2, A. J. Smit6, T. Probyn7 & S. Peall8

1Botany Department, UCT2Department of Systems Ecology, Stockholm University

3Beijer Institute, Stockholm, Sweden

4Seaweed Research Unit, MCM 5Botany Department, UWC

6School of Biological and Conservation Sciences, UKZN 7Aquaculture Unit, MCM

8Hearshaw and Kinnes Laboratory, UCT

Robertson-Andersson Deborah1,5; J. J. Bolton1, M. Troell2,3, R. J. Anderson4, G. Maneveldt5, C.

Halling2, A. J. Smit6, T. Probyn7 & S. Peall8

1Botany Department, UCT2Department of Systems Ecology, Stockholm University

3Beijer Institute, Stockholm, Sweden

4Seaweed Research Unit, MCM 5Botany Department, UWC

6School of Biological and Conservation Sciences, UKZN 7Aquaculture Unit, MCM

8Hearshaw and Kinnes Laboratory, UCT

OverviewOverview

An overview on the development of seaweed aquaculture in

temperate Southern Africa.

The current drivers for integrated seaweed aquaculture.

An integrated abalone seaweed system.

Economic benefits & inter-linkages abalone farming and seaweed

cultivation.

Socio-economic effects and multiplier effects.

Seaweed utilization history: Seaweed utilization history: South AfricaSouth Africa

& Namibia& Namibia

Southern Africa has a recent history of seaweed utilization.

Beach cast harvest started in the 1940’s.

Driver - Shortages of algal based colloids caused by WWII.

Gelidium picking on South African east coast

Kelp harvesting on South African south and west coastsREFS: Isacs 1942, 1953

Anderson et al. 1989

REFS: Isacs 1942, 1953Anderson et al. 1989

Seaweed utilization history: Seaweed utilization history: NamibiaNamibia

Seaweed cultivation first started in Radford bay, Lüderitz Namibia in the

1980’s.

Cultivation of Gracilaria gracilis occurred in 4 - land based, semi-inter-tidal

ponds.

By fertilizing with urea, they obtained a 10 fold increase in production over a

90 day period.

Driver - Commercial production of Gracilaria for agar to supplement

beach cast harvests.

Pictures from Google EarthPictures from Google Earth

REFS: Rotmann 1987Anderson et al. 1989, 2003

REFS: Rotmann 1987Anderson et al. 1989, 2003

Seaweed utilization history: Seaweed utilization history: NamibiaNamibia

Moved to pump ashore ponds then…

In Lüderitz Bay, rope raft cultivation of G. gracilis was started in the 1990’s.

Production was 80 t y-1 in a 4 hectare area.

Driver - High pumping and other capital costs of pond cultivation.

G. Gracilis being threaded onto “Netlon”

Rope rafts in Lüderitz Bay Harvested using traditionalfishing boats REFS: Anderson et al. 1989, 2003

Dawes, 1985REFS: Anderson et al. 1989, 2003

Dawes, 1985

Seaweed utilization history: Seaweed utilization history: South South AfricaAfrica

Seaweed cultivation on an experimental scale first started in Saldanha Bay in the

1990’s using methods adapted from Namibia with G. gracilis.

Cultivation was successful and there was evidence of integration, with fish factory

wastes being taken up by the Gracilaria.

Driver - Disappearance of G. gracilis wash-ups due to natural and

anthropomorphic events.

Medium to small beach wash up

1970’s – 1980’s

Little to no wash up

Present dayREFS: Anderson et al. 1989, 2003REFS: Anderson et al. 1989, 2003

Seaweed utilization history: Seaweed utilization history: South South AfricaAfrica

SGR was 5 % d–1, and a yield of 39.6 t.d.wt.ha–1y–1.

Commercial production did occur twice and experimental cultivation

also occurred in St Helena bay.

Failures due to - Thermal stratification in the bay during summer resulting in a

lack of nutrients available to the seaweeds and high

temperatures.

Fouling by mussels and tunicates.

H2S killing all seaweeds following die off of algal blooms.

Final harvestExperimental raftMonitoring of linesREFS: Anderson et al. 1989, 2003REFS: Anderson et al. 1989, 2003

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Abalone production WW Kelp as abalone feed WW

beach cast DW

Seaweed utilization history: Seaweed utilization history: South South AfricaAfrica

In the 1990’s abalone farming started using Haliotis midae.

Ecklonia maxima was used as a feed source for farms on the

western and South west cape coasts.

Driver for seaweed cultivation on land - Lack of and decrease in kelp

resource to feed increasing industry.

Kelp concession areas being harvested at 60 – 99 % of their MSY.

Kelp harvest vs. kelp demand as abalone feed

Position of abalone farms round coast line

Seaweed cultivation history: Seaweed cultivation history: Eastern Eastern CapeCape

From 1992 to present, 25 Masters and Honors projects looked

at land based cultivation of seaweeds. Most looked at

cultivation in flow- through systems, utilizing a variety of

species.

In 2000, 2 farms in the eastern cape built a total of 34 paddle

ponds cultivating Ulva and G. gracilis based on this research.

Driver - Food source for abalone - high seawater

temperatures cause artificial feed to ferment and bloat

abalone.

Kelp doesn’t grow in the eastern cape.

Paddle ponds on a flow through system

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Mixed diet

Rotation

Fresh Kelp

Fresh Kelp + formulated feed

Formulated feed

In 2000 research on 2 abalone farms in the western cape looked at the

use of seaweeds as biofilters and a feed source. Ultimately to develop

an integrated abalone seaweed system.

Drivers – Lack of and decrease in kelp resource to feed increasing industry.

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.

Seaweed cultivation history: Seaweed cultivation history: Western Western CapeCape

Effect of diets on abalone growth rates

Naidoo et al. 2006Naidoo et al. 2006

Seaweed cultivation history: Seaweed cultivation history: Western Western CapeCape

Effect of harvesting on regrowth of obligate epiphytes on kelp

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In 2000 research on 2 abalone farms in the western cape looked at the

use of seaweeds as biofilters and a feed source. Ultimately to develop

an integrated abalone seaweed system.

Drivers – Lack of and decrease in kelp resource to feed increasing industry.

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.

Anderson et al. 2006Anderson et al. 2006

Seaweed cultivation history: Seaweed cultivation history: Western Western CapeCape

Red tide moving towards abalone intake

In 2000 research on 2 abalone farms in the western cape looked at the

use of seaweeds as biofilters and a feed source. Ultimately to develop

an integrated abalone seaweed system.

Drivers – Lack of and decrease in kelp resource to feed increasing industry.

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.

The aims of this research were:

Characterise how seaweeds perform, specifically seaweed SGR,

nutrient absorption capacity, nutritional quality and epiphytic

assemblages.

Are the cultivated seaweeds suitable as a

food source?

What was the biofilitering capacity?

Seaweed cultivation: Seaweed cultivation: Western CapeWestern Cape

Small & medium tanks using abalone or fish effluent

Large tanks used 5 x 1 m

y = -0.4557x + 3.2565p < 0.05

0

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B-B scale of infection

SGR

(% D

ay)

BAD INFECTION

DEAD

RESULTS: RESULTS: Myrionema strangulans Myrionema strangulans (new record & range (new record & range

extension)extension)

HEALTHY

INFECTED

RESULTS: RESULTS: Tissue Nitrogen vs. Thallus Tissue Nitrogen vs. Thallus ColourColour

Seaweed tank Seaweed tank

3 KW.hr pump3 KW.hr pump

Gravity feed Gravity feed

Abalone tanksAbalone tanks

Seaweed tank Seaweed tank

25 % Recirculation 25 % Recirculation

75 % Sea water 75 % Sea water

Over flow Over flow

Pilot scale integrationPilot scale integration

5.0

7.0

9.0

11.0

13.0

incoming sea Seaw eed tanks

RESULTS: RESULTS: Dissolved oxygen (mg.LDissolved oxygen (mg.L-1-1))

15 16 20 00 04 08 12 16 20 00 04 08 12 16

5

7

9

11

13

Incoming sea 25 % Recirculation Seaw eed tanks

RESULTS: RESULTS: Dissolved oxygen (mg.L-1)Dissolved oxygen (mg.L-1)

15 16 20 00 04 08 12 16 20 00 04 08 12 16

Dissolved oxygen transfer 33 % loss from seaweeds to abalone

tanks.

RESULTS: RESULTS: Temperature (Temperature (ºC)ºC)

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12

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22

27

Incoming sea Seaw eed tanks 15 16 20 00 04 08 12 16 20 00 04 08 12 16

RESULTS: RESULTS: Temperature (Temperature (ºC)ºC)

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12

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27

Incoming sea 25 % Recirculation Seaw eed tanks 15 16 20 00 04 08 12 16 20 00 04 08 12 16

Temperature 4 % higher in integrated tanks over 18

month period

Results:Results: Nutrient uptakeNutrient uptakeResults:Results: Nutrient uptakeNutrient uptake

Nutrient analysis showed the system to be nitrogen limited and that the system was very efficient at removing nitrogen based wastes.

Nutrient analysis showed the system to be nitrogen limited and that the system was very efficient at removing nitrogen based wastes.

% difference in nutrient

uptake efficiency FAN TAN PO4 NO3 NO2

25 % Recirc. abalone vs. FTS abalone

54.85 38.06 0 64.8 48.8

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Other results:Other results:Other results:Other results:Seaweed SGR

Tissue nutrients

Abalone health

Bacteria

Sediments

Abalone growth rates

Mobile macro fauna

Seaweed SGR

Tissue nutrients

Abalone health

Bacteria

Sediments

Abalone growth rates

Mobile macro fauna

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25 % Recirc. FTS

No significant differencesNo significant differences

Potgieter, 2005Potgieter, 2005Lindstrom, 2006Lindstrom, 2006 Brandt, 2006Brandt, 2006Flodin, 2005Flodin, 2005Hansen, 2006Hansen, 2006Robertson-Andersson, 2003, 2007Robertson-Andersson, 2003, 2007Sankar, 2003Sankar, 2003Bredberg, 2003Bredberg, 2003

Commercial integrated seaweed abalone system:Commercial integrated seaweed abalone system: 50 % recirculation50 % recirculationCommercial integrated seaweed abalone system:Commercial integrated seaweed abalone system: 50 % recirculation50 % recirculation

Intake Intake

Seaweed paddle ponds Seaweed paddle ponds

Sump Sump

Drum filter Drum filter

Abalone

tanks

Abalone

tanks

Header tank Header tank

Pump Pump

Seaweed harvest

point

Seaweed harvest

point Outlet Outlet

FEED SAVINGS:

4 ponds produce 120 tons of feed a year at a cost of ZAR 1

100 therefore a direct rand value of ZAR 132 000.

The cost of 1 ton of kelp ranges from ZAR 950 – ZAR 1 250

per ton with a FCR of between 1: 12.5 – 17 (I & J farm data).

Cultivated Ulva has an FCR of 1: 3.6 (I & J farm data) due to its

higher protein content and this means that the

equivalent feed value is ZAR 478 500.

SEAWEED PADDLE POND SYSTEM: SEAWEED PADDLE POND SYSTEM: Costs and savingsCosts and savingsSEAWEED PADDLE POND SYSTEM: SEAWEED PADDLE POND SYSTEM: Costs and savingsCosts and savings

ZAR 360 000 to build 4 ponds

SEAWEED PADDLE POND SYSTEM:SEAWEED PADDLE POND SYSTEM: Costs and savings Costs and savings

SEAWEED PADDLE POND SYSTEM:SEAWEED PADDLE POND SYSTEM: Costs and savings Costs and savings

ZAR 360 000 to build 4 ponds

PUMPING SAVINGS:

Due to the reduced head heights when pumping the total savings

from having this system is an average of 20 KW.h-1.

Electricity costs per KVA are around 16 c per unit (bulk usage for Gansbaai

district, ESKOM, 2006).

If we assume that the power correction factor for a pump is equal

to 1, then 1 KVA is equal to 1 KW.

A 20 KW saving over a year would equal ZAR 20 032.

SEAWEED PADDLE POND SYSTEM:SEAWEED PADDLE POND SYSTEM: Costs and savings Costs and savings

SEAWEED PADDLE POND SYSTEM:SEAWEED PADDLE POND SYSTEM: Costs and savings Costs and savings

ENVIRONMENTAL SAVINGS:

The seaweeds take up 345 tons of CO2 y-1

An additional 345 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

SEAWEED PADDLE POND SYSTEM:SEAWEED PADDLE POND SYSTEM: Costs and savings Costs and savings

SEAWEED PADDLE POND SYSTEM:SEAWEED PADDLE POND SYSTEM: Costs and savings Costs 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, 541 thousand Euro yr-1) and

indirect environmental benefits (estimated as the value of the

externalities, 53,200 Euro yr-1)

ZAR 12.79 = € 1 ZAR 12.79 = € 1

SEAWEED PADDLE POND SYSTEM: SEAWEED PADDLE POND SYSTEM: NegativesNegativesSEAWEED PADDLE POND SYSTEM: SEAWEED PADDLE POND SYSTEM: NegativesNegatives

Two farms which feed Ulva and Gracilaria exclusively

experienced that their abalone developed an ‘off’ taste

and sulphur-like smell after the canning process.

Taste and smell due to evolution of DMS from DMSP.

Caused when abalone ingest algae high in DMSP

particularly cultivated U. lactuca.

DMS in cans up to 44 μg.ml-1.

Taste threshold of DMS in water about 1000 times lower

However, abalone with high DMSP concentrations are

preferred in the raw state.

Two farms which feed Ulva and Gracilaria exclusively

experienced that their abalone developed an ‘off’ taste

and sulphur-like smell after the canning process.

Taste and smell due to evolution of DMS from DMSP.

Caused when abalone ingest algae high in DMSP

particularly cultivated U. lactuca.

DMS in cans up to 44 μg.ml-1.

Taste threshold of DMS in water about 1000 times lower

However, abalone with high DMSP concentrations are

preferred in the raw state.

A A A

A A

B

B

B

B

B

B

B B

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C

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C C

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D

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E E

E E

Uncooked Cooked

ABALONE

SEAWEED

CULTIVATIO

N in 2006

SEAWEED

HARVEST

CANNIN

G

ABFEE

D

Laborers 814 12 388 (600 –

1000)

67 16

Tonnage (tons) 850 1056 11019 150 360

Pay (ZAR) 1813 1813 1484 2464 2464

UnSkilled (%) 61 85 88 0 50

Male :female 1:0.23 1:0 1:2 1:0.23 1:0

Investment (ZAR) 346 500

000

3 760 000 260 000 000 2 000 000 750 000

Socio-economic effects from seaweed Socio-economic effects from seaweed cultivation in comparison to abalone cultivation in comparison to abalone

farming and related industries in SA in farming and related industries in SA in 20052005

Conclusion:Conclusion:

Integrated seaweed cultivation has developed due to economic drivers,

mainly from the abalone cultivation industry.

The fact that U. lactuca is the largest aquaculture product in temperate

Southern Africa is testament to the success of this type of aquaculture.

This development has only been possible through cooperation between

research institutions and commercial enterprises.

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