A pilot scale integrated seaweed (Ulva lactuca) & abalone (Haliotis midae)

recirculation system

Deborah V. Robertson-Andersson1,6; Michelle, Potgieter1, Joakim, Hansen2; John J. Bolton1, Max Troell2,3, Robert J. Anderson4,

Christina Halling2, Trevor Probyn5

1Botany Department, UCT2Department of Systems Ecology, Stockholm University

3Beijer Institute, Stockholm, Sweden

4Seaweed Research Unit, MCM 5Aquaculture Unit, MCM

6Biodiversity & Conservation Biology, UWC

INTRODUCTIONINTRODUCTION

Previous studies in Israel and South Africa have shown that Ulva lactucais capable of removing significant amounts of nutrients (60 – 85 %) from aquaculture effluents

These systems were built on vertical integration

They were generally open/flow though systems

Often included fish as with a high waste production

Advantages of a closed systemAdvantages of a closed system

+ Increase in temperature above

ambient seawater equates to

an increase in growth rates

+ Decrease in pumping costs due

to reduced head heights

+ Additional safety in times of red tide

and oil spills

+ Benefit of additional food source

Disadvantages of a closed systemDisadvantages of a closed system

- Excessive sediment build up.

- Higher bacteria concentrations.

- Reduction in water quality.

- Increased occurrence of diseases or parasites.

- Stress in abalone.

- Decreased growth of abalone.

- Changes in physico- chemical variables.

AIMSAIMS

1) Investigate the physico-chemical dynamics.

2) Investigate sediment build up and composition.

3) Investigate growth rates of seaweeds and abalone.

4) Investigate disease, parasite and pest organisms.

5) Seasonal changes in the above.

6) Investigate water quality.

Flow through vs. Recirculation system

PROJECT DESIGN @ I & PROJECT DESIGN @ I & JJ

2 Ulva tanks (5 X 1 X 0.63 m) were integrated to one abalone tank (7 X 2 X 1 m).

Run under normal farm operating conditions.

Control were 3 flow through abalone tanks.

Seaweeds initial stocking density 2.5 kg m-2.

Harvested every two weeks.

+ 13 200 abalone (10 – 15 g) total starting biomass 165 kg.

75 % fresh seawater input (3 200 L h-1).

25 % recirculated from seaweeds (800 L h-1).

Seaweed tank Seaweed tank

PumpPump

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

Seaweed tank Seaweed tank

PumpPump

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

RESULTSRESULTS

Abalone SGRAbalone SGR

20

30

40

50

60

70

80

90

Jun-03 Oct-03 Jan-04 Apr-04 Aug-04 Nov-04 Feb-05 May-05 Sep-05

Leng

th (

mm

)

25 % Recirc. FTS

RESULTSRESULTS

Ulva lactuca Ulva lactuca SGRSGR

0

5

10

15

20

25

30

35

Jan-

04

Mar

-04

May

-04

Jul-0

4

Sep

-04

Nov

-04

Jan-

05

Mar

-05

May

-05

Jul-0

5

Sep

-05

Nov

-05

Ulv

a b

iom

ass

(kg

/tan

k)

Recirculation Fertilized flow through

RESULTSRESULTS

Myrionema strangulans Myrionema strangulans GrevilleGreville andand

Fissurella mutabilisFissurella mutabilis Sow.Sow.

0

1

2

3

4

5

6

May-04 Jul-04 Aug-04 Oct-04 Dec-04 Jan-05 Mar-05 May-05

B-B

sca

le o

f d

ensi

ty

25 % Recirc.

FTS

M. strangulans

y = -0.4557x + 3.2565p < 0.05

0

2

4

6

8

0 1 2 3 4 5 6

B-B scale of infection

SG

R (

% D

ay)

RESULTSRESULTS

Ulva lactuca Ulva lactuca SGR vs. large scale environmentSGR vs. large scale environmentAdvectionAdvectionUpwelling Upwelling Warm water intrusionWarm water intrusion

12

13

14

15

16

17

18

19

20

21

22

23

24

04

/02

/01

04

/02

/15

04

/02

/29

04

/03

/14

04

/03

/28

04

/04

/11

04

/04

/25

04

/05

/09

04

/05

/23

04

/06

/06

04

/06

/20

04

/07

/04

04

/07

/18

04

/08

/01

04

/08

/15

04

/08

/29

04

/09

/12

04

/09

/26

04

/10

/10

04

/10

/24

04

/11

/07

04

/11

/21

04

/12

/05

04

/12

/19

05

/01

/02

05

/01

/16

05

/01

/30

05

/02

/13

05

/02

/27

05

/03

/13

05

/03

/27

05

/04

/10

05

/04

/24

05

/05

/08

05

/05

/22

Te

mp

era

ture

(o C)

Recirc Control Seaweed Incoming sea

www.rsmarinesa.org.za

RESULTSRESULTS

Ulva lactuca Ulva lactuca SGR vs. environmentSGR vs. environment

0

5

10

15

20

25

30

35

Jan-

04

Mar

-04

May

-04

Jul-0

4

Sep

-04

Nov

-04

Jan-

05

Mar

-05

May

-05

Jul-0

5

Sep

-05

Nov

-05

Ulv

a b

iom

ass

(kg

/tan

k)

Recirculation Fertilized flow through

RESULTSRESULTS

Dissolved oxygen concentrationsDissolved oxygen concentrationsThere was a There was a 33 % loss33 % loss of oxygen from the seaweed tanks to the of oxygen from the seaweed tanks to the abalone tanks.abalone tanks.Dissolved oxygen in the abalone tanks flow through system was Dissolved oxygen in the abalone tanks flow through system was 4 % 4 %

higherhigher than those in the recirculation system. than those in the recirculation system.

4

5

6

7

8

9

10

11

04/02

/01

04/03

/01

04/04

/01

04/05

/01

04/06

/01

04/07

/01

04/08

/01

04/09

/01

04/10

/01

04/11

/01

04/12

/01

05/01

/01

05/02

/01

05/03

/01

05/04

/01

05/05

/01

05/06

/01

Diss

olved

Oxy

gen (

mm

g.l-1

)

Recirc OUT Control OUT Seaweed OUT dailyS OUT

RESULTSRESULTS

Nutrient uptakeNutrient uptake

% 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

RESULTSRESULTS

Bottom sediment accumulationBottom sediment accumulation

0

2

4

6

8

10

12

FTS 25 % Recirc.

Dry

mass (

mg

/L)

50 < µm 40 - 50 µm 30 - 40 µm 20 - 30 µm

P < 0.01

RESULTSRESULTS

Other ResultsOther ResultsSedimentsSediments

Weekly accumulationWeekly accumulationWater columnWater column

BacteriaBacteriaVibrioVibrio’s’sTotal bacteriaTotal bacteria

Abalone healthAbalone healthSabellidsSabellidsGeneral conditionGeneral conditionInternal parasites (Gut protozoa, Internal parasites (Gut protozoa, RickettsiaRickettsia))Gonad histologyGonad histology

CONCLUSIONSCONCLUSIONS

There are no negative effects on abalone health or growth There are no negative effects on abalone health or growth rates from being included in a 25 % Recirculation rates from being included in a 25 % Recirculation

systemsystemBenefitsBenefits of such a system are of such a system are

Decreased sediments in water columnDecreased sediments in water columnDecreased Decreased Vibrio’sVibrio’s bacterial counts bacterial countsIncreased temperatureIncreased temperatureThe ability to protect from external harmful influencesThe ability to protect from external harmful influences

NegativesNegatives in this system in this systemLow phosphate uptakeLow phosphate uptakeLow oxygen transferLow oxygen transferGreater temperature variation in winterGreater temperature variation in winter

SO what next….SO what next….

You build a full scale system!!!!You build a full scale system!!!!

SO what next….SO what next….

Commercial integrated seaweed abalone system:Commercial integrated seaweed abalone system: 50 % recirculation 50 % 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 Quality: Feed Quality: Tissue Nitrogen vs. Thallus Tissue Nitrogen vs. Thallus ColourColour

6

8

10

12

14

16

18

20

22

24

26

28

30

Aug-02

Sep-0

2

Oct-0

2

Nov-02

Dec-0

2

Jan-

03

Feb-0

3

Mar

-03

Apr-03

May

-03

Mea

n w

et w

eig

ht

(g)

Mixed diet

Rotation

Fresh Kelp

Fresh Kelp + formulated feed

Formulated feed

Tis

sue

pro

tein

co

nte

nt

(mg

N.g

)

Food Quality: Food Quality: HumansHumans

Food Quality: Food Quality: HumansHumans

Taste test questionnaire

Dear taste tester

Thank you for agreeing to be a part of this

testing programme.

Testing will be done using two taste test approaches:

A) A quantitative descriptive analysis

B) A difference test (triangle test)

The purpose of this test is three fold:

1) To rank you as a tester

2) To evaluate which is the most acceptable abalone diet

3) To compare all the taste samples to a reference smell of DMS

This will be done for both cooked and raw abalone.

Food Quality: Food Quality: HumansHumans

Taste test questionnaire

Dear taste tester

Thank you for agreeing to be a part of this

testing programme.

Testing will be done using two taste test approaches:

A) A quantitative descriptive analysis

B) A difference test (triangle test)

The purpose of this test is three fold:

1) To rank you as a tester

2) To evaluate which is the most acceptable abalone

diet

3) To compare all the taste samples to a reference

smell of DMS

This will be done for both cooked and raw abalone.

Food Quality: Food Quality: HumansHumans

Food Quality: Food Quality: HumansHumans

Food quality changes with:Food quality changes with:• Tester categoryTester categoryUC -UC -farmersfarmers: taste intensity, : taste intensity,

acceptability of textureacceptability of textureAsianAsian: taste and odour : taste and odour characteristicscharacteristics

C - C - farmersfarmers: sweetness and odour : sweetness and odour freshnessfreshnessAsianAsian: bitterness, sourness: bitterness, sourness

• Sample preparationSample preparationUC -surface texture, colour, aroma UC -surface texture, colour, aroma

intensityintensityC - C - surface texture, colour, visual and surface texture, colour, visual and

taste freshness, sweetnesstaste freshness, sweetness

• DietDietUC - wild-caught vs. rest: odour UC - wild-caught vs. rest: odour

intensity, colour; Ulva-fed vs. rest: intensity, colour; Ulva-fed vs. rest: texture (visual and touch)texture (visual and touch)

C - separation more pronounced; each C - separation more pronounced; each feed-type influenced by a different feed-type influenced by a different sensory variablesensory variable

THANK THANK YOUYOU

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

Frontier Program