Use of additives - Transport of Live Fish

Use of additives

Many additives are available that can be added to the transport water to improve the transport results and allow fish transport over longer periods.

Instead of using filters and water re-use systems, additives can be applied to the water to give similar effects. Addition of seawater to freshwater will have a positive pH regulating effect because of its buffer-ing capacity. The same will be the case with addi-tion of other buffering substances. Sodium chloride can be added to freshwater as a defoaming agent. Addition of clinoptilolite to the water (as used in an ion exchanger) will reduce the concentration of ammonia.

Addition of salt may reduce osmoregulatory disturbance, and by this the total stress when trans-porting freshwater fish. Antibiotic can be added to reduce the development of bacteria in the trans-ported water.

Addition of sedatives, such as MS222 and clove oil, to the transport water may also be done to calm the fish down and reduce the metabolic rate. This will reduce oxygen consumption and decrease the excess of carbon dioxide and ammonium ion; the fish will also tolerate more stress.

All use of additives will, however, require accurate control of the water quality during transport; they may not always function or the effect may be minor. It is best therefore normally to avoid using additives. Adding of antibiotics and sedatives ought to be avoided unless there are very special conditions pertaining to the live transport. These may not be allowed before the fish go to process-ing plants because they may leave residues in the flesh.