Exploring the potential of bath sponge aquaculture in Torres Strait

Alan Duckworth, Carsten Wolff, John Morris, Samson Lowatta, Simon Naawi, Paul Lowatta and

Patterson Mosby

Australian Institute of Marine Science

Yorke Island Community Council

Torres Strait Regional Authority

CRC Torres Strait

Colleagues

Surveyed Torres Strait for a good bath sponge

• July 2004• 4 locations• 25 sites• 10,000 m2

surveyed

• Coscinoderma bath sponge abundant at Yorke Islands

• Sponge up to 50cm in length• Quality spongin• MOU between AIMS and YICC• 5 sponge divers from Yorke

Developing a good farming method

• Farming methods– Mesh panels: spider panels (SP) and monofilament panels (MP)– Threaded line: nylon line (NL) and polypropylene line (PL)– Mesh panels then threaded rope (nursery): SP – NL and SP – PL

• Two sites: Masig and Kodall Islands• 216 Coscinoderma explants (sponge pieces)• December 2004, ran for 9 months

Survival

% s

urv

iva

l (+

/- 1

S.E

.)

0

20

40

60

80

100

Growth

SP MP NL PL SP-NL SP-PL

% o

f ini

tial s

ize

(+

/- 1

S.E

.)

0

50

100

150

200

250

300

Method: P = 0.002Site: P > 0.05

Method: P = 0.02Site: P > 0.05

Final survival and growth among farming methods

Finding a good farming site and examine importance of farming season

• Sponges transplanted in summer and winter• Farmed at 6 and 12 m, but results combined for

analysis

Survival

% s

urvi

val (

+/-

1S

.E.)

0

20

40

60

80

100

Growth

Kodall NW Masig E Masig N

% in

itial

siz

e (+

/- 1

S.E

.)

0

50

100

150

200

250 SummerWinter

Site: P > 0.05Season: P > 0.05

Site: P > 0.05Season: P = 0.02

Sponge survival and growth after 6 months

Optimal initial explant size Survival

% s

urvi

val (

+/-

1S

.E.)

0

20

40

60

80

100

Growth

small medium large

% in

itial

siz

e (+

/- 1

S.E

.)

0

20

40

60

80

100

120

140

160

180

P = 0.03

P = 0.02

Small40 cm3

medium100 cm3

large300 cm3

Optimal harvest regime

• Maximize amount of biomass for explant production, without damaging wild population

• 1/3 and 2/3 of biomass removed

Dec 04, before harvest Dec 04, after harvest Mar 06

Sponge growth after harvesting

Months after harvesting

0 2 4 6 8 10 12 14 16

% o

f in

itial

siz

e (

+/-

1S

.E.)

0

20

40

60

80

100

120

140

1601/3 harvested2/3 harvested

Specific growth rates: P > 0.05

In 2007….

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