1. Ranching, cages, net pens... How low can you go? Lecture 14: FAS 1012

2. As traditional aquaculture and fishing practices have increases, so have the needs for alternatives.

3. Cage culture, ocean ranching and net pens have come under intensive development recently.

4. 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” to large cages or net pens” “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” to large cages or net pens”

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

6. Disadvantages Water quality may be harder to manageWater quality may be harder to manage Higher potential for disease outbreakHigher potential for disease outbreak Vandalism is easierVandalism is easier

7. Site Selection At least one surface acreAt least one surface acre Average depth of 4 ft.Average depth of 4 ft. No more than 10 acre watershed perNo more than 10 acre watershed per acre of water. No direct access by livestockNo direct access by livestock No chronic problems with weeds.No chronic problems with weeds. No silt or pesticide runoff.No silt or pesticide runoff.

8. Cage Considerations InvestmentInvestment Management AidManagement Aid –Observation –Feeding –Treatment Design – MaterialsDesign – Materials HarvestHarvest OverwinteringOverwintering

9. Cage Construction FloatationFloatation MeshMesh –1/8 to 1/4 for Phase I (1-2”) –3/4 for Phase II (6-8”) Feeding RingFeeding Ring

10. Water Quality TemperatureTemperature –70ºF+ Dissolved OxygenDissolved Oxygen –4 ppm+ NitritesNitrites –<10ppm pH 6.5-9.0pH 6.5-9.0 TurbidityTurbidity –Around 24” AlkalinityAlkalinity –40 ppm+ AmmoniaAmmonia –<1ppm

11. Cage Placement in Pond Cages should be placed where water can move freely between cages and circulate away from immediate area of cages.

12. Stocking Phase Stock 1-3 in. fingerlings.Stock 1-3 in. fingerlings. Stock when water temperature is >55 o F.Stock when water temperature is >55 o F. Stock around 25-35 fingerlings per ft 3.Stock around 25-35 fingerlings per ft 3.

13. Stocking Advanced Fingerlings In the Midwest need to stock AT LEAST a 6” fingerling with an 8 in. fingerling preferred.In the Midwest need to stock AT LEAST a 6” fingerling with an 8 in. fingerling preferred. Stock when water temperature is >55 o F.Stock when water temperature is >55 o F. Stock 6-8 fingerlings per ft 3.Stock 6-8 fingerlings per ft 3.

14. Feeds JuvenilesJuveniles –Non floating –Crumble size particle –40% CP or greater Advanced FingerlingsAdvanced Fingerlings –Floating pellets –36% CP acceptable

15. Feeding JuvenilesJuveniles –Feed often and plenty –Hand feeding or automatic feeders Advanced FingerlingsAdvanced Fingerlings –Morning and afternoon best –Hand feeding... advantageous, but slow advantageous, but slow

16. Management Grading of fingerlingsGrading of fingerlings Predator ControlPredator Control Weed Control in PondsWeed Control in Ponds Algae Control on CagesAlgae Control on Cages

17. Diseases Columnaris early in the season or from handling stress.Columnaris early in the season or from handling stress. Gill FlukesGill Flukes Cannibalism among some small fish an issue.Cannibalism among some small fish an issue.

18. Harvesting If fish are stocked in April,If fish are stocked in April, then should be market size by late October (for HSB). Forewarned is forearmed…Forewarned is forearmed… Be prepared!!

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

20. Economics Break-even price for 5,000 lb production was $1.27/lb for HSB.Break-even price for 5,000 lb production was $1.27/lb for HSB. Based on: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