Arcata Marsh and Wildlife Sanctuary
Aquaculture Methods and Materials
All the information on this page gas been referenced from studies done
by
Dr. George Allen in 1990 and 1991
Method and Materials Index
Effluent Delivery System
The
Hatchery
Closed
System Incubator
Recirculating Rearing System
Effluent Delivery System
Pump and Piping for bringing treated wastewater into the South and Yearling Ponds began
in 1990 for imprinting coho smolts. In April of 1991 the system was opened as a
continuously flowing system through all the ponds, before it had been a static system
between the two Yearling Ponds, to allow the passage of water for imprinting the smolts.
This is a list of materials used for the rearing and imprinting ponds:
- The water levels during low tide fall. For this, the outlets for the
Ponds are baffled to provide a 2-foot water level during low tide.
- Near the headgates of each pond a pump was installted to allow for the
mixing of salt and wastewater.
- A 4-inch knife valve controls the salinity of the water after it passes
through a 27-cubic-foot concrete mixing box fitted with a forced-air aeration unit to
provide the proper oxygen content in the water and allow for the control of possible
deadly substances like ammonia.
- To allow a continuous flow of water from Yearling Pond 1 to Yearling
Pond 2 a 4-inch pipe was installed from Yearling Pond 1 to Yearling Pond 2 and an 8-inch
pipe was installed from Yearling Pond 2 to Yearling Pond 1 to provide a reverse flow.
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The Hatchery
This is the area where the fish eggs were first brought in to hatch and then allowed to
grow from fingerlings to fry
and later released into the Yearling Ponds to reach their smolt
stage of life.
Closed System Incubator
Egg incubation uses four banks of Heath Trays, with 8 trays per bank.
Water is pumped from an underground 500-gallon reservoir. Water returning from the
incubators to the reservoir passes through a counter current foam fractionator that
removes egg enzymes and dissolved organics located in the reservoir. Water leaving the
incubator passes through a short commercial-type plastic Bio-Media fixed-film reactor for
additional water quality treatment (Allen, 1989).
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Recirculating Rearing System
Fry and fingerlings are reared in another recirculating system adjacent
to the ponds. This system contains 2,000 gallons total volume of water with a maximum flow
of 45 grams-per-minute and comprises these units:
- A two-chamber reservoir fitted with a plastic floor matting, volcanic
rock, and oyster shell.
- 3 trickling filter units contained in plastic and oyster shell media
with water fed to the media by rotating spray bars.
- A greenhouse unit of about 200-gallon capacity utilizes pennywort, a native plant, to remove nitrogen.
- Recirculated water is passed through a UV-sterilizer, removes harmful
microscopic organisms that might have entered the system.
- Conditioning of the water utilizes bacterial beds prior to fish rearing
and is suplemented with aqua-bacta-aid (ABA) bacterial media that helps reduce nitrogen
dioxide and ammonia.
Methods and Materials Index
Aquaculture
These pages are under
construction