Definission: Active swimming organisms that live in the water column and are able to move independently of the water mass (adapted from Lincoln et al., 1998).
Definission: Description of the relationships among individuals within a population of organisms, including reproductive relationships (mating system), relationships within each sex, adult – young interactions, helpers and cooperation (group living).
Definission: where individuals of the same species (conspecifics), maintain spatial proximity with one another over time with mechanisms of social attraction
Definission: A group of species that exploit the same food resources, and/or use the same feeding or foraging methods. http://en.wikipedia.org/wiki/Guild_(ecology)