Bahamas Researching sustainable cobia mariculture from

breeding to market Use artificial mangroves for waste water treatment Grow out in offshore, deep water (40-90 ft deep)

submerged sea stations Capacity of 120 tons a year

http://www.youtube.com/watch?v=ZZr246dBTAo

Cape Eleuthera Institute

Aquaculture of CobiaRachycentron canadum

Cobia are Awesome!

Sport fishing“Aquapod” Offshore environmentally friendly

containment

Grow to 78 inches long and 135 pounds Strong pelagic swimmers Strong fighters and are “Sport fish” Very fast growing in comparison to other fin

fish Meat has great texture, few bones, and

great taste

Impressive Statistics

Big Fish

Raised for food! Gaining economic importance in Southeast

Asia and China Good tasting/texture flesh and fast growth

make it a potentially good species for mariculture

Has potential to outrun salmon in commercial success.

Grows faster than salmon

Economic Importance

Yum!

Top five producers◦ Taiwan◦ Pakistan◦ Philippines◦ Brazil◦ United Arab Emirates

Countries looking into culture due to economic value◦ U.S.A.◦ China◦ Taiwan

Countries of Importance

In Taiwan ◦ Produce 13-17lb market size fish (export to Japan)◦ Produce 17-22lb fish for domestic consumption◦ Sells for about $2.50 per lb.◦ Costs about $1.10 per lb. to culture◦ Produced more than 5000 tons in 2004

In Puerto Rico◦ $3-$4 per lb. ◦ Shipped to Miami

In China ◦ About $2-$3 per lb. (~$45 for 17lb fish)

Market price is higher than most other finfish

Natural Range of Cobia

Spawn in aggregations, release many small planktonic eggs

Eggs hatch 24-36 hours after fertilization Planktonic larvae 2.5 mm long After five days develop eyes and mouth,

begin feeding At 30 days look like small adult Sexually mature at 2-3 years Live to about 12 years (135#)

Life Cycle

Larval and Juvenile Cobia

Larvae at 12 days oldA. Late larval stage >6 daysB. Juvenile >30 days

Brood stock are kept in tanks or ponds◦ Larvae can also be purchased for culture

They are triggered to breed with ◦ Natural water temperature changes◦ Hormonal additions to the water

Eggs are hatched out in recirculation tanks◦ They float and are just scooped out of the water

larvae are fed started about 3 days after hatching

Reproduction in Captivity

Breeding Stock

Recirculation Systems used for Hatchery and Nursery

Also Green water ponds◦ Fed rotifers at 3 days◦ Microalgae and Artemia nauplii at 7 days

High density larval rearing can give low survival rate ◦ Lowering the density can raise the survival rate

The larvae are size graded at least 3 times before grow out to reduce cannibalism

Production Methods for Hatchery

Incubation and Hatching Tank

• 2000L cone shaped tank• Flow through system• 20L/min flow speed

Open net cage method◦ Used in most places it is cultured

Offshore technology being developed◦ In the US and Bahamas

Recirculation systems ◦ Suitable and in development

Ponds◦ Used in some countries

Production Methods for Grow Out

Ready for Grow Out

Recirculation Systems for eggs and larvae◦ Target temperature range 28-29C◦ Optimal salinity 25ppt (not to exceed 35ppt)◦ pH close to 8◦ High levels of aeration◦ D.O. 8-9 mg/L

Grow out systems need similar conditions to warm tropical and subtropical waters◦ Temperature is most important◦ Must be done in warm areas

Water Chemistry

Larvae eat very small planktonic organisms Adult fish are carnivorous

◦ Crabs, Squids, Shrimp, Fish In captivity are generally fed commercial

fish meal◦ Other options are being studied

Feeds and Feeding

Advantages Disadvantages Very fast growing Good economic

investment (good return) Great tasting and popular

meat Fare well in cultured

environments May keep wild populations

safer if meat available from culture

Ongoing research to address problems

“up and coming” species

Some problems with juvenile survival rates in intensive systems and transportation

Carnivorous diet hard to replicate without fish meal which has environmental concerns

Cage systems have same environmental concerns as salmon and other large cages fishes