Environmental Resources

Unit CAnimal Wildlife Management

Problem Area 3

Fish Management

Identifying fish facilities and stocking rates.

Lesson 6

Identifying fish facilities and stocking rates.

• What are some different types of structures in which humans can live?

• What are some of the advantages and disadvantages to each of these structures?

• What about the types of facilities in which fish live?

Terms

• Cage• Closed System• Levee• Levee-type Ponds• Permeability Rate

• Raceways• Stocking Rate• Tank• Watershed Ponds

Objectives

• Identify fish production facilities.• Understand how to select sites for

aquaculture facilities.• Describe the importance of properly

stocking a fish production facility.

What are some common fish production facilities?

• Type of facility to produced fish depends on: – Type of fish raised– Size and scope of

operation– Available location

• Common facilities include:– Levee-type pond– Watershed pond– Raceway– Cages– Tanks

Levee-type ponds

• Levee-type– Building levees on

nearly land.

• Levee– Manmade structure

composed of soil and other earthen materials used to hold water.

– Material brought in from an outside source.

http://www.bogor.indo.net.id/kri/ponds.htm

Levee-type ponds

• Water for these ponds are from wells.• Water is only added when level drops too

low.• Production of catfish in the southern

United States.

Watershed Ponds• Damming a natural flowing

stream.• Constructed by taking

advantage of natural hills and valleys.

• Bottom of pond is uneven causing difficulty when harvesting.

• Water is added only to replace lost water.

Raceways• Structures that allow

water to move through rapidly.

• Takes of advantages of natural streams and springs to provide the water.

• Takes advantages of sloping land to allow water to move through system.

• Trout commonly produced in raceways.

Cages • Constructed of netting on a wood or metal frame placed in an existing body of water.

• Can be used in levee-type ponds, watershed ponds, streams, rivers, lakes or oceans.

• Disadvantage is fish cannot eat material through water must be fed more.

• Catfish, bream, and tilapia often raised in cages.

Tanks• An artificial water enclosure.• Available in a wide variety of

shapes and sizes.• Part of a closed system

– Reuses the same water by recalculating it after it has been filtered and re-oxygenated.

How are sites selected for aquaculture facilities?

• Site selection for an aquaculture facility depends on:– Amount of needed land.– Proximity to market sand suppliers.– Weather of the area.– Availability of necessary infrastructure.

• electricity, roads, telephone lines– Each type of facility has its own criteria.

Levee type pond requirements• Flat land• Soil that will hold water.• Not prone to flooding.• Land high enough to be

drained.• Slow permeability rate.

– Speed at which water flows through the soil.

• Source of clean water.

• Clean water is usually from a well.

• Test well for quality and quantity.

• If spring is used.• Test the flow to

ensure enough water is available.

Watershed pond requirements

• Similar to levee-type. • Exception is hills and

valleys are wanted.• Soils with the ability to

hold water.• Soils with high clay

content are excellent.• Additional clay may

need to be added.

• Water source is usually a stream.

• Test water of stream for water quality and enough flow to meet the needs.

Raceway requirements

• Biggest factor is the source of continuous flow of water.

• Usually a stream that can be diverted through raceway.

• Land to be gently sloping for water to flow through raceway.

www.ncagr.com/aquacult/fort.html

Cage facility requirements1. Water must flow

through cages.• Fish cannot move

through the water so water must move through.

2. Water must be deep enough.• Water must move

under the cages.www.aquafact.ie/Aquaculture.html

Tank requirements• Can be placed almost

anywhere.• Biggest factor is the

proximity to needed supplies, roads and utilities.

• A good well to provide water.

• A place to discharge used water. www.sun.ac.za/kie/unistel/

aquaculture/aquastel

Why is properly stocking a fish production facility important?

• Stocking rate– Pounds of fish per gallon of water.– Quality of water is a large factor.– Vary by species of fish.– Overstocking and understocking can cause

problems.

Why is properly stocking a fish production facility important?

• Overstocking– Can cause fish

health problems.– Filters may not be

able to effectively clean water.

– Can lead to oxygen depletion in water.

– Food source may not be adequate enough.

• Understocking– Can cause

production to be below the potential of facility.

– Expense of constructing a facility may not be reached fast enough to recover invested money.

Review / Summary

• What are some common fish production facilities?

• How are sites selected for aquaculture facilities?

• Why is properly stocking a fish production facility important?