SEA CUCUMBER AQUACULTURE RESEARCH

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1 BECHE-DE-MER MARKET IN THE PACIFIC REGION Bêche-de-mer Evisceration, boiling, dry Sandfish 95% weight loss Export of sea cucumbers (fresh/frozen/dried/salted/in brine) from Pacific countries* Quantity Value Quantity (tonnes) % of world export Value (million US$) Export to: China, Japan, Korea Rep., Malaysia, Singapore, Taiwan PC, Thailand Source: FAO FISHDAB, 2003 * Fiji Islands, French Polynesia, Kiribati, Marshall Islands, New Caledonia, Papua New Guinea, Samoa, Solomon Islands, Tonga, Vanuatu SEA CUCUMBER AQUACULTURE RESEARCH New Caledonia, Boulouparis Australia, Cairns Philippines, Bolinao November 2006 Natacha Agudo 1

2 HATCHERY & NURSERY FACILITIES Green house, 150 m 2 Indoor hatchery, 70 m 2 - Algal room & laboratory - Spawning area - Larval rearing area - Nursery area Outdoor hatchery under cover, 220 m 2 SEAWATER & AIR SUPPLY - Sandfilter - Cartridge filters (25, 10, 1 µm) - UV units Blowers 2

3 SANDFISH BROODSTOCK Sandfish, Holothuria scabra - High commercial value specie - Ripe animals > 200 g - Impossible to distinguish males from females externally - Biopsy or dissection New Caledonia Australia Mean weight (g) 534 ± 23 (sea pen) 628 ± 33 (beginning, pond) 968 ± 38 (end, pond) 334 ± 7 (wild) 256 ± 8 (pond) Weight range for females (g) 237 Weight range for males (g) Philippines 262 ± 16 (sea pen) Males: 100 & 540 g BROODSTOCK MAINTENANCE Density rate < g/m 2 Earthen pond, 1300 m 2 Outdoor tanks, 2 m 3 Sea pen, 500 m 2 Sea pen, 9 m 2 3

4 INDUCTION OF SPAWNING - Spawning tank (1 m 3 ): group of animals - Induction methods: dry treatment, thermal shock, Spirulina bath Pre-spawning behavior SPAWNING - Pre-spawning behavior - Distinguish males from females - Egg collection Egg collector Spawning (males & females) (%) Successful spawning (%) Nber of eggs per spawning (million) Nber of eggs per female (million) Survival (eggs to juveniles) (%) New Caledonia Australia Philippines LARVAL REARING - Larval tanks 300 & 500 L 1 m 3 - Protocol of rearing Cylindrical tanks with conical bottom - Initial density: 0.5 1/ml - 30% water exchange from day 2, 1 µm filtered & UV treated seawater - Feeding: mixture of microalgae, to cells/ml 4

5 LARVAL STAGES Microalgae Auricularia, 450 µm 1.1 mm (D2 to D8 10) Pelagic phase Doliolaria, µm (D10 to D13) No feeding Benthic phase Pentactula, <1 mm (since D12) Juvenile, >1 mm (since D15) Diatoms + artificial food SETTLEMENT MONITORING - Preparation for settlement - Settlement surfaces with diatoms - Addition of stimulant & diatoms in tanks - Transfer of early juveniles Pentactula & early juveniles - Transfer at days old (1 2 mm length) - Different methods used: siphoning, draining, using potassium chloride (KCl) 5

6 NURSERY TANKS Canva raceway, 7 m 3 Fiberglass raceway, 4 m 3 Rectangular tank, 600 L NURSERY PHASE - Protocol - Preparation with settlement surfaces and diatoms - Initial density: /m % water exchange, µm filtered seawater - Feeding: diatoms & artificial food - 2 stages: first with settlement surfaces (1 month), second with sand substratum Raceway - Transfer - Between 2 and 3 months old, at around 1 g - Growth rate very heterogeneous - Survival estimated: 50 60% Juveniles 1 2g 6

7 HAPAS & BAG NETS IN PONDS Bag nets, 1 3 mm mesh Hapas, 670 µm mesh Surface of enclosures: 1x1 m, 2x2 m, 3x3 m RELEASE JUVENILES INTO THE SEA - Protocol - Two large-scale experiments conducted from Initial weight range: 1 20 g at various densities of 0.5, 1 & 3/m 2 - Recapture surveys every few months Sea pen, 500 m 2 - Survival & growth - The average survival to market size was estimated to be ~ 9% of sandfish released - Mean weight of g after 1 year but growth rate expected to increase when animals reach ~ 300 g - Expect to take 3 4 years to reach size for A-grade beche-de-mer (1 Kg) - Perspectives - Restocking - Sea ranching: put and take 7

8 GROW-OUT IN PONDS - Protocol Mean weight (g ±SE) Two ponds of 2000 m 2 each, from June Initial mean weight: 0.9 g and 11.7 g with respective density of 1.4 and 0.8/m 2 - Daily water change - No fertilizers, no feeding - Assessment once a month Earthen pond - Survival & growth 50 0 Large juveniles Small juveniles Months - Survival > 73% after 6 months - Mean weight of g after 1 year - Expect to take less than 2 years to reach market size - Perspectives - Grow-out in ponds to 3 10 g before release into the sea, and to market size - Co-culture with salt-adapted tilapia or barramundi? HOW TO IMPROVE AQUACULTURE IN SEA CUCUMBERS? Broodstock management Spawning Growth Survival Fecundity Spawning rate Advantages & disadvantages: - wild populations - in captivity - Ripe broodstock - Spawning season - Induction method - Lunar effect (?) - Spawning management Larval rearing Survival Duration - Stocking density - Water quality & change - Feeding mixture & scheme Settlement & metamorphosis Nursery phase Settlement & metamorphosis rates Growth Survival - Conditioning of settlement surfaces & tanks - Food & feeding rate - Stocking density - Food & feeding rate - Substrate - Density management 8

9 For more information: - Identification cards: Pacific Island sea cucumber and beche-de-mer identification cards (ACIAR, SPC) - Handbook: Sea cucumbers and Beche-de-mer of the tropical Pacific: a handbook for fishers (SPC, 1994) French version: Holothuries et bêches-de-mer dans le Pacifique tropical: un manuel a l intention des pêcheurs - SPC Beche-de-mer Information Bulletin - WorldFish Center Pacific Office in New Caledonia worldfish-newcaledonia@cgiar.org 9