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Molluscan larvae that are competent to set can be shipped damp and cool anywhere that is accessible within about 48 hours from a hatchery. In this case a system was set up for remote setting of Pacific oyster (Crassostrea gigas) larvae in South Korea from larvae shipped from the state of Washington.
Oyster larvae that have been received in South Korea from a remote location are re-suspended in seawater before being dispersed for setting on oyster shell cultch.
At Coast Seafoods in Kona, Hawaii, expanded algae cultures are grown in 125,000 liter tanks using sunlight and primarily cool, nutrient-rich, deep ocean water.
At Coast Seafoods in Kona, Hawaii, a 1.3 meter x 1.3 meter upwell nursery system is used to grow a variety of species from 2mm to 8mm before being shipped off the island for grow-out. Photo courtesy of Dr. Ken Chew - Cover photo of Aquaculture Magazine, Sept/Oct 1998.
2 mm Manila clam (Tapes philippinarum) seed grown in an upwell system. Clams do well in either a semi-recirculating system or a single pass seawater system.
Mussel seed that was set and grown on Koira (coconut fiber) lines in a hatchery in New Zealand. Mussel larvae can either be set and grown in a hatchery or in a remote setting system as long as there is a continuous supply of good quality water and algae grown to supplement the natural standing crop of algae.
Mussel seed can be deployed on grow-out lines once the larvae have firmly adhered to the nursery lines. Successful mussel byssing (attachment) is related to both size and environmental conditions in the nursery. These mussel lines are being deployed for grow-out on continuous longlines in New Zealand.
Mussel larvae will attach well to fibrous surfaces such as these ropes, which can then be deployed for grow-out inside a mussel sock.
Two to three-month old mussel seed (Mytilus galloprovincialis) from the Coast Seafoods hatchery in Quilcene, Washington grown at Penn Cove Shellfish.
Hatchery mussel seed (Mytilus galloprovincialis) from a nursery raft at Penn Cove Shellfish in Washington State.
Oyster larvae can be set on a variety of substrates including pvc pipes. Here pipes that have been set in a hatchery are grown on intertidal longlines for the fresh-shucked oyster meat market
Single oyster seed from a hatchery can be grown in upwell systems in a floating or land-based nursery or in floating trays such as these. Floating trays work well for a low-production facility requiring low capital expenditures and relatively few seed while upwell systems are more efficient for larger seed requirements.
Molluscan larvae can be grown in either a batch or flow-through system. This system in Hawaii was set up with 21 tanks. Flow-through systems are more complex and therefore require more staff attention but they produce healthier larvae at much higher densities than batch cultured larvae.
Molluscan larvae should be set in a downwell system then in most cases switched to an upwell system such as this. Clean efficient systems work best for seed health and growth.
This recirculating upwell system for Coast Seafoods in Kona, Hawaii, contains 20 large upwells, each 1.3 meters x 1.3 meters. Each upweller is capable of holding 200 liters of seed as long as sufficient algae is provided, with a seawater flow-rate per upwell of up to 1500 liters per minute. 200 liters of clam seed at 3-4mm seed size is equivalent to about 20 million animals.
These bottles were set up at Unique Seafarms in British Columbia, Canada for growing Pacific oyster seed from post-set to about 3mm. Bottles provide continuous seawater flow and continuous algae flow on a single pass system. They produce high quality nicely cupped single oysters and can be used in any size hatchery.
This Coke Bottle seed system in Alaska is a new system for Pacific oyster seed production at this location.
There are many seawater filtration systems available. One of the most efficient is this mixed-media system which allows for high flow rates and good filtration for use with larvae and young seed.
In-water seed graders like this one by MPH work best for small clam and oyster seed. Dry graders should be used for larger seed.
This 84' x 25' greenhouse is used for growing algae in bags and algae in tanks in British Columbia, Canada. Algae cultures here use both artificial lighting and sunlight. There is not a lot of solar gain at this site, but there is still a nutritional benefit to the algae from natural sunlight.
Hatcheries do not have to be large. This hatchery was designed using a shipping container for the primary algae cultures, larvae production by flow-thru, and lab. The expanded algae cultures use natural sunlight and the Geoduck clam seed tanks are fish totes and are outside.
Traditional upwell seed nurseries work well but high silt loads can be a problem in some areas, requiring high labor maintenance costs. The best way to manage upwells in this environment is either by extensive filtering or increasing the flow rate to fluidize the seed bed.
Continuous flow algae bag culture produces high quality algae. It works well when used to feed larvae and young seed. It is an intermediate culture step if large numbers of algae cells are required.
Floating upwell systems work well for seed clams and oysters that are 2mm and larger. They are efficient because they use the natural algae in the water rather than cultured algae. Also, flow rates are high with low energy use by using a paddle wheel.
Primary algae culture, larvae rearing and lab space can be accommodated inside a 40 foot shipping container like this one at Western Oyster Company.
Algae bags do not have to be illuminated with artificial light in certain situations. In Hawaii algae grows well with the use of natural sunlight.
Algae that is grown indoors such as this system in Alaska requires high illumination levels. Metal Halide lights similar to this work well to grow all species of algae but especially diatoms.
Broodstock should be suspended in trays off the tank bottom for best broodstock health and ease of cleaning by staff.
Ready to set oyster larvae are added to downwell rings such as these to produce single oysters. In this case the seawater is added by a spray bar at the top of the ring and the water is forced down through the screen on the bottom of the ring. Finely ground and graded shells are added to each ring prior to adding the larvae.
There are 36 two hundred liter research larvae tanks at this new research oyster hatchery at the University of North Carolina at Wilmington facility. These can be operated as either flow-through larvae culture or static larvae culture depending on the number of animals needed for research.
These 200 liter broodstock holding and conditioning tanks are used for maturation of oysters prior to spawning. They have a continuous flow of coarsely filtered seawater and a continuous flow of algae.