One of the most crucial problems of spawning seabass is that the eggs and sperm are not available at the same time; sometimes viable eggs are available but sperm is not, or vice versa. The problem could be achieved by collecting the milt first. Short-term preservation of fish sperm can be achieved by chilling in the refrigerator at a temperature of 4°–8°C. This technique can preserve sperm for five days. Withler and Lim (1982) suggested that the sperm is more active if suspended in 10% of dimethyl sulphoxide before chilled storage.
The long-term preservation technique can be done by storing the fish sperm in liquid nitrogen at a temperature of -196°C. To present cell breakdown due to extremely low temperature, a drop of dimethyl sulphoxide can be mixed with the sperm. By this method the sperm can be kept for about 2 years; and approximately 98 percent survival of sperm is obtained (Bhinyoying, 1980).
