There are population interactions in marine ecosystems to consider. Competition among species plays an important role in ecological regulation. The two forms of competition are: interference (or contest) competition and exploitation (or scramble) competition. Interference competition occurs when the dominant species keeps its competition away from a resource. Scramble competition describes a situation in which a population depletes a resource making it less available to its competition. The amount of competition is increased when resources are limited. Inter specific competition is competition between two or more species populations for limited resources. Intra specific competition is the struggle that occurs between organisms in a population when resources are limited. Mortality, growth, and the ability to reproduce are all related to the number of organisms in a particular environmental niche. When density becomes too high, mortality increases, growth decreases, and the ability to reproduce is inhibited.