INTEGRATING SEAWEEDS INTO SOUTH INTEGRATING SEAWEEDS INTO SOUTH AFRICAN ABALONE AQUACULTURE AFRICAN ABALONE AQUACULTURE John J. Bolton 1 , Deborah M. Robertson-Andersson 1 , Max Troell 2 , Robert J. Anderson 3 , Gavin Maneveldt 4 , Christina Halling 2 , AJ Smit 5 , Trevor Probyn 3 & Sue Peall 1 1 University of Cape Town, South Africa 2 Stockholm University, Sweden 3 Marine & Coastal Management, South Africa 4 University of the Western Cape, South Africa 5 University of KwaZulu-Natal, South Africa John J. Bolton 1 , Deborah M. Robertson-Andersson 1 , Max Troell 2 , Robert J. Anderson 3 , Gavin Maneveldt 4 , Christina Halling 2 , AJ Smit 5 , Trevor Probyn 3 & Sue Peall 1 1 University of Cape Town, South Africa 2 Stockholm University, Sweden 3 Marine & Coastal Management, South Africa 4 University of the Western Cape, South Africa 5 University of KwaZulu-Natal, South Africa
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INTEGRATING SEAWEEDS INTO SOUTH INTEGRATING SEAWEEDS INTO SOUTH
Kelp harvest Kelp harvest vsvs abalone production abalone production ((TroellTroell et al. Aquaculture, in press)et al. Aquaculture, in press)
0
100
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600
1986
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1998
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2003
Tons abalone
0
1000
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7000
Tons kelp
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
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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-02
Sep-02
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-02
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-02
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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: