Spawning area, spawning grounds and spawning beds are considered the locations where commercially important species of fish leave their eggs for fertilisation. Spawn consists of the reproductive cells (gametes) of fish, some of which will become fertilised 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 fertilise the eggs. Spawning grounds help understand the species distribution of a particular commerically important fish.

Marine nursery areas are habitats that promote the survival of young commercially important fish species. Many of these creatures are important to humans in fisheries and seafood. These habitats are essential for the reproduction and understanding of the geographical species distribution. Take them away or degrade them, and the production of commercially harvested species will decline or cease altogether.