Ranching, cages, net pens... How low can you go?

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Ranching, cages, net pens... How low can you go?

• Lecture 5 FAS 1012

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As traditional aquaculture and fishing
practices have increases, so have the needs for
alternatives.
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Cage culture, ocean ranching and net pens have
come under intensive development recently.
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Cage Culture

• is the cultivation of fish in existing
• water resources such as farm ponds, mining pits
  or barrow pits using small
• to large cages or net pens

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Advantages

• One of the only ways to grow fish for sale in
  large deep ponds or lakes.
• If ponds are owned then relatively low startup
  costs.
• Good way to learn aquaculture at a small scale.

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Disadvantages

• Water quality may be harder to manage
• Higher potential for disease outbreak
• Vandalism is easier

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Site Selection

• At least one Surface Acre
• Average depth of 4 ft.
• No more than 10 acre watershed per
• acre of water.
• No direct access by livestock
• No chronic problems with weeds.
• No silt or pesticide runoff.

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Cage Considerations

• Investment
• Management Aid
• Observation
• Feeding
• Treatment

• Design Materials
• Harvest
• Overwintering

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Cage Construction

• Floatation
• Mesh
• 1/8 to 1/4 for Phase I (1-2)
• 3/4 for Phase II (6-8)
• Feeding Ring

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Water Quality

• Temperature
• 70ºF
• Dissolved Oxygen
• 4 ppm
• Nitrites
• lt10ppm
• pH 6.5-9.0

• Turbidity
• Around 24
• Alkalinity
• 40 ppm
• Ammonia
• lt1ppm

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Cage Placement in Pond

• Cages should be placed where water can move
  freely between cages and circulate away from
  immediate area of cages.

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Stocking Phase II

• Stock 1-3 in. fingerlings.
• Stock when water temperature is 55oF or higher.
• Stock around 25-35 fingerlings per ft3.

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Stocking Phase III

• In the Midwest need to stock AT LEAST a 6
  fingerling with an 8 in. fingerling preferred.
• Stock when water temperature is 55oF or higher.
• Stock 6-8 fingerlings per ft3.

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Feeds

• Phase II Production
• Non floating
• Crumble size particle
• 40 CP or greater

• Phase III Production
• Floating pellets
• 36 CP acceptable

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Feeding

• Phase II
• Feed often and plenty
• Hand feeding or automatic feeders
• Phase III
• Morning and afternoon best
• Hand feeding...
• advantageous, but slow

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Management

• Grading of Phase II fingerlings
• Predator Control
• Weed Control in Ponds
• Algae Control on Cages

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Diseases

• Columnaris early in the season or from handling
  stress.
• Gill Flukes
• Cannibalism among Phase II fish

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Harvesting

• If fish are stocked in April
• then should be market size
• by late October.
• Forewarned is forearmed
• Be prepared!!

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Overwintering

• Success depends on condition of fish after
• harvesting and possible winter kills.
• Blowers will keep ice from around the cages.

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Economics

• Break-even price for 5,000 lb production was
  1.27/lb.
• Based on
• five acre pond
• 6 month production cycle
• 75/100 six inch fingerlings
• 1,000 lbs per acre yield

• 10 death loss
• 25/cwt feed
• 2.0 FCR