We would like to give special thanks to Bob Heideman, President of Aquatic Eco-Systems,Inc., for providing us with his expertise in aeration.
This simplified guide is intended to teach the fundamentals of the proper aeration techniques in keeping live bait, and “catch & release” fish, alive and healthy in live wells.
The advantages as well as disadvantages of many types of aeration will be discussed.
UNDERSTANDING THE CONCEPT OF AERATION
There are many misconceived ideas about aeration.
Two common fallacies are:
- Large live wells are required to sustain a large quantity of fish.
- Large live well pumps are needed to move large quantities of water through the live well to keep live bait and fish alive.
To understand what is really needed for proper aeration, it is best to take a parallel look at ourselves and fish.
FACTS FOR HUMANS
If we were enclosed in a large airtight room we would be able to breathe for many hours before we would consume all the oxygen.
If we were in an airtight closet, the oxygen would be consumed a lot quicker.
If we were swimming underwater without a snorkel, the oxygen in our lungs would be consumed very quickly.
In all cases, without additional oxygen we would eventually expire!
However, we could stay alive indefinitely, if we could use a breathing tube or snorkel that was in contact with outside fresh air or oxygen. It would not matter about the size of the container or the quality or air that surrounded us.
FACTS FOR FISH
If we enclosed a fish in a sealed, 1,000 gallon tank, it would survive for a long time before consuming all the oxygen.
If we enclosed the same fish in a sealed 10 gallon tank, the oxygen would be consumed more quickly.
If we removed the same fish from the tank and placed it on a table, the fish could live for an extremely short time.
In all cases, without additional oxygen the fish would eventually die.
However, our fish could stay alive indefinitely if we could put oxygenated water through its gills and keep it wet. It would not matter about the size of the tank.
AN AERATOR IS TO A FISH, WHAT A SNORKEL IS TO US!
SIZE OF AERATORS AND SNORKELS
It is more difficult to breathe through a straw than through a large snorkel.
A small or ineffective aerator cannot provide as much oxygen in the water as a larger or more effective one.
If an aerator can provide enough oxygen in the water for the fish to breathe, it doesn’t matter how much water surrounds the fish! The only reason that water must be changed occasionally in live wells is to remove ammonia. The smaller the container of water, the more frequent the changing.
BASIC REQUIREMENTS OF AERATION
There are two major considerations in aeration.
- The gentleness and direction of water flow
- The size and amount of the air bubbles
- The temperature of the water
GENTLENESS AND DIRECTION OF WATER FLOW
FISH THAT SWIM IN SCHOOLS Delicate bait such as shad, green-backs and croakers will not survive a day of fishing unless the water flow in the well is soft and gentle. Turbulent water will damage the bait and force them to work against the current. Ideal water flow within the well should be approximately 1 to 2 MPH, and in a circular motion. This will allow fish to school and provide a smooth flow of water over and through their gills. If the water flow is excessive, bait tire quickly and will not be lively. Keep water flow as low as possible, with fish swimming in a stationary position within the tank.
SHRIMP AND FISH THAT DO NOT SCHOOL Species that do not school do not need a circular or oval container. Keep water flow to a minimum for fish such as bass, redfish, crappie, bream, and walleye.
For shrimp, provide material in the well so they can cling and not be swirling about the well and become damaged. Leave a dip net in the well, or tie a stone in a piece of cloth such as burlap.
SIZE AND AMOUNT OF AIR BUBBLES
Take a look at at the air bubbles produced by an aquarium aerator. Watch how quickly the bubbles rise to the surface. They provide little aeration, but are aesthetically pleasing to watch. Bubbles must remain contacting the water, if they are to do the job properly. A good rule of thumb is: The smaller the bubble, the longer it will remain suspended in water to dissolve.
The warmer the water, the less oxygen it will hold. Fish will deplete the oxygen quicker as the water warms, and poor aerators will maintain less fish. Colder water will hold more oxygen. Water frozen in a plastic bottle will lower temperatures and keep the chlorine out of the tank.
Use an aquarium thermometer to compare temperatures. Keep temperatures within eight degrees Farenheit between water in the well, and water outside the boat.
CAUTION: Placing fish in different temperatures quickly will shock and kill them. It is best to place fish in the same water and temperatures where they were caught.
A Lesson in Air Bubbles
by Bob Heideman of Aquatic Eco-Systems, Inc.
The smaller the air bubble, the more slowly it will rise, giving it more time to dissolve in the water.
Due to the higher density of salt water, air bubbles are usually smaller in salt water than in fresh water.
A large 20mm bubble has a volume of 4.19 cm3, and a surface area of 12.6 cm2.
You could make 260 small 3mm bubbles from the large bubble. They would have a total surface area of 83.6 cm2. This is 6.6 times the surface of the 20mm bubble.
The small bubbles, can theoretically aerate 6.6 times as much water with the same amount of air.
Knowing the importance of air bubble size, the effectiveness of different aerator systems becomes readily apparent!
Livewells come in many shapes and sizes. Oval or round tanks provide the best circulation. However, rectangular or square wells are satisfactory if there is a directional discharge into the well. The directional discharge will induce the more desirable circular motion.
Species that do not school, do not need a circular or oval container. Keep water flow to a minimum for fish such as bass, redfish, crappie, bream and walleye. They do not need a water flow for survival.
For shrimp, provide material in the well so they can cling and not be swirling about the well and become damaged. Leave a dip net in the well or tie a stone in a piece of cloth such as burlap.
AIR VERSUS OXYGEN
Oxygen will maintain higher quantities of fish, but extra care must be taken when using pure oxygen. To understand the fundamentals or air versus oxygen, each should be individually discussed.
A human breathes in oxygen and gives off carbon dioxide (CO2). The CO2 is then dissipated into the atmosphere.
A fish breathes in oxygen from the water and gives off CO2. The CO2 is absorbed into the surrounding water. The CO2 is then dissipated into the atmosphere through the process of aeration.
An air bubble as it passes through water has the ability to put oxygen into the water and also absorb CO2 as it passes slowly to the surface. The bubble then pops at the surface and the CO2 is dissipated into the atmosphere. The smaller the bubble, the longer it remains in the water to exchange oxygen and CO2.
An oxygen bubble will insert a higher percentage of oxygen into water than a normal air bubble. This allows for higher quantities of fish in a given size of container, or it will make bait fish lively. However, an oxygen bubble does not have the ability to absorb CO2. As the fish eliminates CO2 in it