 Most aquatic animals, except for aquatic mammals and reptiles, reproduce through the process of spawning.Spawn consists of the reproductive cells (gametes) of many aquatic animals, some of which will become fertilized and produce offspring.The process of spawning typically involves females releasing ova (unfertilized eggs) into the water, often in large quantities, while males simultaneously or sequentially release spermatozoa (milt) to fertilize the eggs.