Stock Management Issues

1
Stock Management Issues
Michael B. Timmons Ph.D. J.Thomas Clark Professor
of Entrepreneurship Personal Enterprise Cornell
University
2
Production Strategies

• Continuous production strategies
• can double total system production
• compared to batch strategies
• rely on year round stocking and harvesting
• maintains the system near its carrying capacity
• ideal situation
• not always attainable

3
Stock Management Issues

• Batch strategy
• P/B 1.74/yr,
• ts th 224 days N0 1965

4
Stock Management Issues

• Concurrent batch stocking and harvesting
• P/B 3.14/yr
• ts th 56 days N0 1125

5
Stock Management Issues

• Concurrent mixed-stocking and graded harvesting
• P/B 3.48/yr
• ts 56 days th 14 days N0 1438

6
Stock Management Issues

• For gt 5 years, Freshwater Institute produced
  rainbow trout
• 4.6 MTON annual production
• 1.0 MTON maximum biomass
• stocked every 8 weeks at 30 to 40 g
• harvested weekly at 340 g
• 1 mm/day growth
• vs. 21 to 41 annually for many commercial farms

7
Stock Management Issues

• Harvesting and grading
• IMPORTANT!
• can add considerably to labor cost!
• mechanism/strategy must be incorporated with
  culture tank design.
• Automated fish grading/pumping equipment
• reduces labor costs
• can reduce fish stress and damage

8
Harvesting and Grading

• Small box graders work well at small scale.

9
Harvesting and Grading

• Clam-shell graders reduce labor and are easy on
  fish!

10
Harvesting and Grading

• Clam-shell graders reduce labor and are easy on
  fish!

11
Harvesting and Grading

• Belt graders and roller graders handle large
  numbers.

12
Harvesting and Grading

• Counting channels track fish numbers after
  grading.

13
Harvesting and Grading

• Moving fish is hard work!
• Fish moving equipment
• fork lift a palletized tank
• fish pumps
• heli-arc
• vacuum
• pescalator
• swim fish through channels and raceways

14
Tank Access Tank Enclosures

• Was tank access designed into the tank layout?