Mussels in the context of "Clumping (biology)"

Clumping is a behavior in an organism, usually sessile, in which individuals of a particular species group close to one another for beneficial purposes. Clumping can be caused by the abiotic environment surrounding an organism. Barnacles, for example, group together on rocks that are exposed for the least amount of time during the low tide. Usually, clumping in sessile animals starts when one organism binds to a hard substrate, such as rock, and other members of the same species attach themselves afterwards. Herbivorous snails are known to clump around where sufficient algae are present. The clumping of mussels (shown right) has been found to be influenced by competition with other species. The mussels attach themselves by byssal threads to potential competitors for space.