Breathing Bags� are a completely new approach to the shipping of live fishes, as well as aquatic invertebrates and aquatic plants, in plastic bags. The special plastic film used in the Breathing Bags generates the constant transfer of carbon dioxide out of the water in the bag through the walls of the bag, and the absorption of oxygen from the atmosphere though the bag walls into the water in the bag. This provides a constant source of fresh oxygen for the breathing of the fishes and other aquatic life.
Kordon � Breathing Bags� represent a new approach to the problems of shipping live fishes and other aquatic animals and aquatic plants, including over long distances or for extended time periods. The product development staff at Kordon, teamed with plastics chemical engineers, have taken a technology first developed in space/military research and refined it to produce the bags being offered today.
The Breathing Bags allow the transfer of simple and complex gas molecules through the plastic wall of the bag -- carbon dioxide and oxygen in particular, as well as other gases - providing a true "breathing" bag in place of a "barrier" bag as is used in plastic polyethylene bags. As long as there is a breathable atmosphere outside the Breathing Bag, the animals inside will not run out of oxygen.
Carbon dioxide exits the bags at 4 times the rate oxygen enters the bags, thereby constantly purging the water of toxic carbon dioxide, and allowing oxygen to replace it in the water. Kordon has shipped around the world millions of bags (termed "Sachets") of living foods (tubifex worms, brine shrimp, daphnia, glass worms, etc.) for aquarium fishes using the Breathing Bag technology, and hundreds of thousands of Breathing Bags have been used successfully to ship fishes, coral reef animals, and aquatic plants.
Prior to this invention, the only plastic bags available for shipping fishes and aquatic invertebrates were made of polyethylene and had no mechanism to allow the passage of gasses through the bag wall. When using these "barrier" bags, any oxygen must - of necessity - be added as a gas inside the bag prior to sealing.
This process has many problems. High concentrations of oxygen can cause flammable conditions. The presence of oxygen gas inside the bag takes up a lot of valuable shipping space. Once the supplied oxygen is used up there is no more available.
Toxic carbon dioxide from the fishes' breathing builds up in the water, displacing the oxygen. The oxygenated air in the bags may not be satisfactory for fishes' breathing, because (particularly from sources in underdeveloped countries), the bottled oxygen may be contaminated. A bag partially full of water with the rest filled with oxygen allows the contents to slosh during transport, stressing fishes.
METHODS OF USE FOR FISHES AND AQUATIC INVERTEBRATES
After adding water and fishes or aquatic invertebrates to the Breathing Bag, seal the bag with no airspace or with as little airspace as possible.
Except for those few kinds of air-breathing fishes that are made uncomfortable by the lack of an air space at the surface, fishes adapt readily to the lack of an airspace and it is not needed. It is best if there is no air pocket in the bag so that there is no water movement, keeping the fishes calmer. An unneeded air space also uses up valuable shipping space.
Breathing bags can be sealed using all of the current methods: rubber bands, twist ties, metal clips, etc. An even better way for fast efficient sealing is with a bar type heat sealer. The plastic used in the "Breathing Bags" readily seals with heat. Heat sealing can be done much more quickly than other methods and greatly increases the speed with which bags can be handled and sealed. For those sealing many bags for shipment the change will be a dramatic reduction in labor.
The plastic in the "Breathing Bags" is surprisingly tough and flexible. The thickness is 1.5 mil for the regular bags and 3 mil for the liner bag. [Note: 1.5 mil is 1.5 thousandths [10-1.5] of an inch [0.0254 x 1.5] thick....3 mil is double that thickness.]
Small punctures such as from fish spines often do not penetrate the plastic, and if they do, the molecular structure of the plastic tends to realign and reduce the size of the holes or reseal itself. Some fishes may damage the bag film enough to cause leaks or ruptures. Only experimentation and experience will determine which individual species of fishes are safe to transport, without leakage. However, even if there is some leakage, absorptive materials in the shipping box can be used to take care of it, without the boxes leaking.
For spiny fish and aquatic invertebrates that tear the Kordon Breathing Bags, it is recommended to use a vegetable produce bag perforated with holes, such as those used for grapes, fitted inside the Breathing Bag to help with the puncture problem. For most smaller spiny fishes it is sufficient to multiple bag them, Breathing Bag within Breathing Bag, preferably with the inner bag wrapped in one or more layers of wet paper. Another way with less breathability is to have water in both the inner and outer Breathing Bag. There is a proportionate loss of breathability (up to approximately 50%) for one bag inside another, which will affect different animals differently. The user should experiment to find acceptable conditions for multiple bagging.
Breathing Bags function well when packed in conventional foam plastic or corrugated boxes. Foam and cardboard boxes have a high rate of breathability, even if these containers are sealed with tape. Air is normally over 21% oxygen, which is over 210,000 ppm (parts per million). Aquatic invertebrates and fishes normally have only about 4-14 ppm oxygen available to them in water. I
It takes only a small amount of air passing through the packaging materials to sufficiently oxygenate the water in the Breathing Bags. This is even true for shipping boxes in an air cargo space that is not pressurized. There is sufficient oxygen at higher altitudes for the aquatic life in the Breathing Bags. If it is required for some special purpose, additional oxygen can be added to the Breathing Bag as is done in the traditional barrier bag. The Breathing Bag will retain the oxygen for several days.
Higher temperatures increase the "breathability" of the bags, the rate at which oxygen and carbon dioxide is exchanged.
When packing individual bags in shipping boxes, it is best to separate each bag, such as with flat pieces of corrugated cardboard or layers of newspaper, wrapping paper, or plastic "peanuts," so that as much bag surface area as possible is exposed to the air in the shipping container. These materials are completely porous to air and oxygen.
Breathing Bags should not be shipped inside a "barrier" type plastic liner bag. The barrier effect of the outer non-breathing bag will prevent the Breathing Bags from performing properly.
During tests, fishes, both freshwater and marine, have survived for one month and more in shipment, including on successive flights and land transportation. However, there is no uniform answer as to how long individual shipments will survive using Breathing Bags. There are many variables. Under a wide range of conditions it should be weeks for successful shipments. It is suggested that tests be conducted at the user's facility to determine the proper parameters for successful use of these bags.