INTEGRATING SEAWEEDS INTO SOUTH INTEGRATING SEAWEEDS INTO SOUTH

AFRICAN ABALONE AQUACULTUREAFRICAN ABALONE AQUACULTURE

John J. Bolton1, Deborah M. Robertson-Andersson1,

Max Troell2, Robert J. Anderson3, Gavin Maneveldt4,

Christina Halling2, AJ Smit5, Trevor Probyn3 & Sue

Peall1

1University of Cape Town, South Africa

2Stockholm University, Sweden

3Marine & Coastal Management, South Africa

4University of the Western Cape, South Africa

5University of KwaZulu-Natal, South Africa

John J. Bolton1, Deborah M. Robertson-Andersson1,

Max Troell2, Robert J. Anderson3, Gavin Maneveldt4,

Christina Halling2, AJ Smit5, Trevor Probyn3 & Sue

Peall1

1University of Cape Town, South Africa

2Stockholm University, Sweden

3Marine & Coastal Management, South Africa

4University of the Western Cape, South Africa

5University of KwaZulu-Natal, South Africa

OverviewOverview

Abalone farming in South Africa

Importance of seaweeds (kelp) as feed in SA abalone farming

Prospects for aquacultured seaweeds as feed

Initiation of commercial multi-trophic integrated aquaculture

Abalone landings in South Africa: Abalone landings in South Africa: 1948 1948 -- 20042004

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““Abalone farming in South Africa has Abalone farming in South Africa has

developed rapidly and the country is now the developed rapidly and the country is now the

second largest producer outside Asiasecond largest producer outside Asia””..

World Aquaculture March 2003World Aquaculture March 2003

(750 tons produced in 2005)

Durban

Port ElizabethCape Town

Abalone Operations in South Africa

I&J Abalone

Atlantic Fishing

Foodcorp

Farmprops

Marine Growers

HIKAbahowe Farm

Hermanus Abalone

Aquafarm Development

Dezzo Trading

Avuca Abalone

Fish Bay Mariculture

Foster Keith John

Jacobsbaai Sea Products

Blue Cap General Trading

Seige Investments

West Coast Abalone

Port Nolloth Sea Farms

Ritztrade

Really Useful Investments

Wild Coast Abalone

Abalone industry development in SAAbalone industry development in SA

West coast

(kelp beds)

South coast

(no kelp beds)

Kelp harvesting (Kelp harvesting (EckloniaEcklonia and and LaminariaLaminaria))

Photos: RJ Anderson

SA kelp resources (seaweed concession areas)SA kelp resources (seaweed concession areas)

Anderson et al. (2003)

Kelp harvest Kelp harvest vsvs abalone production abalone production ((TroellTroell et al. Aquaculture, in press)et al. Aquaculture, in press)

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Tons abalone

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Abalone production Kelp as abalone feed (WWt) beach cast (DWt)

Seaweed concession areas and kelp MSYSeaweed concession areas and kelp MSY

187252405010399Totals

112751158155011 (2)

0999519568 (3)

528543486447 (3)

8783389726806 (3)

3546069611655 (3)

Beach cast

(t f wt)

Total Harvest as % of MSY

Harvest(t f wt)

MSY(t f wt)

Concession Area

(MCM Data: from Troell et al. Aquaculture, in press).

Feed as %age of running costs of the Feed as %age of running costs of the

South African abalone industry:South African abalone industry:

KELP: ca. 11%

ARTIFICIAL FEED: ca. 6%

- mostly ABFEED®:

- (Marifeed Property Ltd., South Africa)

- Formulated feed containing fishmeal,

soya bean meal, starch, vitamins and

minerals

Integrated aquaculture: Growing Ulva and Gracilaria in abalone effluent as feedIntegrated aquaculture: Growing Integrated aquaculture: Growing UlvaUlva and and

GracilariaGracilaria in abalone effluent as feedin abalone effluent as feed

Initial research on south coast, where there is no

kelp (University of Port Elizabeth, now NMMU),

more recently in current project

Our research has shown that feeding cultivated

seaweeds to abalone had a number of benefits:

Increased growth rates,

Improved vigour and stress resistance

Initial research on south coast, where there is no

kelp (University of Port Elizabeth, now NMMU),

more recently in current project

Our research has shown that feeding cultivated

seaweeds to abalone had a number of benefits:

Increased growth rates,

Improved vigour and stress resistance

Seaweed cultivationSeaweed cultivationSeaweed cultivation

Integrated aquaculture: Growing Ulva in abalone effluent as feedIntegrated aquaculture: Growing Integrated aquaculture: Growing UlvaUlva in in

abalone effluent as feedabalone effluent as feed

Our research supports that of a number of

previous studies:

Cultivated seaweed (e.g. Ulva) contains much

higher levels of protein than natural seaweed

Cultivated seaweed is an excellent and value-

added feed for South African abalone

Our research supports that of a number of

previous studies:

Cultivated seaweed (e.g. Ulva) contains much

higher levels of protein than natural seaweed

Cultivated seaweed is an excellent and value-

added feed for South African abalone

Abalone weight (g) on different diets after 9 months (Naidoo et al. J. Appl. Phycol., in press)

Abalone weight (g) on different diets after 9 Abalone weight (g) on different diets after 9

months months ((NaidooNaidoo et al. J. et al. J. ApplAppl. . PhycolPhycol., ., in press)in press)

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Mean wet weight (g)

Mixed diet

Rotation

Fresh Kelp

Fresh kelp + Abfeed

Abfeed

Benefits of a mixed algal diet

KELP ONLY

DIET

MIXED ALGAL

DIET

Growing abalone feed in South Africa? A reality: Wild Coast Abalone (south coast, near East London)

Growing abalone feed in South Africa? A reality: Wild Coast Abalone (south coast, near East London)

Integrated aquaculture: Growing Ulva and Gracilaria in abalone effluent as feedIntegrated aquaculture: Growing Integrated aquaculture: Growing UlvaUlva and and

GracilariaGracilaria in abalone effluent as feedin abalone effluent as feed

Two farms which feed Ulva and

Gracilaria exclusively experienced

that their abalone developed an ‘off’

taste and sulphur-like smell after

the canning process

Two farms which feed Ulva and

Gracilaria exclusively experienced

that their abalone developed an ‘off’

taste and sulphur-like smell after

the canning process

DMSP and DMS DMSP and DMS DMSP and DMS

Trace concentrations of a volatile sulphur compound,

Dimethylsulfide (DMS), were discovered in the Earth's

atmosphere about three decades ago.

The gas was also found to occur in ocean surface waters.

Some phytoplankton synthesize the molecule

dimethylsulfoniopropionate (DMSP)

DMS is released by algal cells following death and ‘sloppy

feeding’ by zooplankton.

DMS a naturally produced biogenic gas essential for the Earth's

biogeochemical cycles.

Some algal species contain a high concentration of intercellular DMSP

It is theorized that DMSP may act as either:

an osmolyte (in response to salinity changes),

a cryoprotectant,

An antioxidant in both micro- and macroalgae.

DMS can be formed by the enzymatic cleavage of DMSP to DMS and acrylate, as

well as by the oxidation of DMSP with OH-, oxygen or hydrogen peroxide

Some algal species contain a high concentration of intercellular DMSP

It is theorized that DMSP may act as either:

an osmolyte (in response to salinity changes),

a cryoprotectant,

An antioxidant in both micro- and macroalgae.

DMS can be formed by the enzymatic cleavage of DMSP to DMS and acrylate, as

well as by the oxidation of DMSP with OH-, oxygen or hydrogen peroxide

H3C

C

C

O

OH

C

H3C

S+

HH

H H

DMSPDMS

DMSP and DMS in algaeDMSP and DMS in algaeDMSP and DMS in algae

DMSP and DMS in herbivores DMSP and DMS in herbivores DMSP and DMS in herbivores

DMSP is not produced by animals

DMSP may accumulate in some herbivores following feeding on a DMSP-rich

diet

DMSP is taste- and odourless

Offensive, ‘off’ tastes and smells are associated with DMS

Animals lack the enzyme DMSP-lyase that converts DMSP to DMS

DMS may be produced from DMSP post mortem in animals via:

bacterial DMSP-lyase activity (decay)

heat treatment (e.g. canning)

DMSP is not produced by animals

DMSP may accumulate in some herbivores following feeding on a DMSP-rich

diet

DMSP is taste- and odourless

Offensive, ‘off’ tastes and smells are associated with DMS

Animals lack the enzyme DMSP-lyase that converts DMSP to DMS

DMS may be produced from DMSP post mortem in animals via:

bacterial DMSP-lyase activity (decay)

heat treatment (e.g. canning)

Preliminary investigations Preliminary investigations Preliminary investigations

Papers by Hill et al. (2000, 2004)

Giant clams (which have ‘zooxanthellae’)

developed ‘off-odours’ after death due to

DMSP…

Papers by Hill et al. (2000, 2004)

Giant clams (which have ‘zooxanthellae’)

developed ‘off-odours’ after death due to

DMSP…

Is DMS was detectable in abalone?

1 – 2 g of tissue was removed from 5 abalone fed a

mixed (kelp, Ulva and Gracilaria) diet.

Measurement of DMS:

Quantitative conversion of DMSP to DMS through

alkali hydrolysis

DMS analysis via gas chromatography

Is DMS was detectable in abalone?

1 – 2 g of tissue was removed from 5 abalone fed a

mixed (kelp, Ulva and Gracilaria) diet.

Measurement of DMS:

Quantitative conversion of DMSP to DMS through

alkali hydrolysis

DMS analysis via gas chromatography

Preliminary investigations Preliminary investigations Preliminary investigations

Preliminary investigationsFlesh partitioningPreliminary investigationsPreliminary investigations

Flesh partitioningFlesh partitioning

Top o

f foot

foot

EpipodialEpipodial frillfrill

AM BF F

TF

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35DMSP (µg.g-1)

DMSP values from various tissue types in mixed diet cultivated abaloneDMSP values from various tissue types in mixed diet cultivated abalone

Preliminary investigations Preliminary investigations Preliminary investigations

TF

F

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AM

Top of foot

Epipodial frill

Bottom of foot

Abductor muscle

Diet experimentDiet experimentDiet experiment

5

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10

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20

n

17.0 + 6.40.1 (grac)Gracilaria + Ulva

0.4 + 0.0Gracilara + kelp

0.3 + 0.20Abfeed

87.3 + 24.735.3 + 10.6Ulva

0.2 + 0.1

Diet DMSP

(mmol.kg -1)

0.6 + 0.3Kelp + Abfeed

9.3 + 1.5Kelp + Ulva

+Gracilaria

0.6 + 0.6Kelp

Abalone DMSP

(mmol.kg -1 )

Diet experimentDiet experimentDiet experiment

1087.3 + 24.735.3 + 10.6Ulva

5

5

n

17.0 + 6.40.1 (grac)Gracilaria + Ulva

Diet DMSP

(mmol.kg -1)

9.3 + 1.5Kelp + Ulva +Gracilaria

Abalone DMSP

(mmol.kg -1 )

Values for tridacnid clams are 30 mmol.kg -1 (can be 50–60 mmol�kg–1),

(previously the highest recorded in animals: Hill et al. 2004))

Typical values for fish, crustaceans and other molluscs are below 3 – 4

mmol.kg-1 (Hill et al. 2000)

Values for tridacnid clams are 30 mmol.kg -1 (can be 50–60 mmol�kg–1),

(previously the highest recorded in animals: Hill et al. 2004))

Typical values for fish, crustaceans and other molluscs are below 3 – 4

mmol.kg-1 (Hill et al. 2000)

Depuration experimentDepurationDepuration experimentexperiment

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Time (days)

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DMSP remaining (µg.g-1)

smallest

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large

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DMSP (µg.g-1)

Wild abaloneWild abaloneWild abalone

> 1 000 g

250 – 750 g

100 -200 g

10 -20 g

Small

Medium

Large

Smallest

To DMSP or not to DMSP?To DMSP or not to DMSP?To DMSP or not to DMSP?

Wild abalone and cultured

abalone that eat seaweed

have levels of DMSP

Is DMS an important

component in abalone for

optimal taste?

Taste tests …..

Integrated abalone/seaweed aquaculture in South Africa: the future?Integrated abalone/seaweed aquaculture Integrated abalone/seaweed aquaculture

in South Africa: the future?in South Africa: the future?

I&J Abalone: Gansbaai

January 2006

120t farm extension

Planning for 50% re-circulation

1.7t of Ulva produced per pond

per two week period

THANK YOUTHANK YOU

ACKNOWLEDGEMENTS

Sweden/South Africa Collaborative Programme (SIDA/NRF)

I & J Mariculture farm

JSP Mariculture farm

Abagold

JSP