information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles


Independent Free-living,  individual organisms.
Parasite Parasitism (parasite) - an organism that lives in or on another living organism (the host), from which it obtains food and other requirements. The host does not benefit from the association and is usually harmed by it. (cf. commensalism, mutualism, symbiosis) (McLeod, 1996)
Ectoparasitic Parasitic on the outer surface of its host (adapted from Lincoln et al., 1998).
Endoparasitic Parasitic within the tissues or organs of its host.
Symbiotic Symbiosis, the living together in a constant and definite relationship of two different organisms (cf. commensalism, mutualism, parasite) (Brusca, 1980).
Mutualist (Mutualism) Mutualism (mutualist) - a symbiosis in which both organisms benefit, frequently a relationship of complete dependence. (Lincoln et al., 1998) (cf. symbiosis, commensalism, parasite).
Inquilinist Inquilinism (inquilinist) - symbiotic association in which one symbiont lives in close association with another, generally in the tube or burrow or actually within a body chamber of the host (Brusca, 1980).
Commensal (with/on/in) Commensalism (commensal) - symbiosis (q.v.) in which one species derives benefit from a common food supply, whilst the other species is not adversely affected (Lincoln et al., 1998).


  • Brusca, R.C., 1980. Common intertidal invertebrates of the Gulf of California. University of Arizona Press.
  • Lincoln, R., Boxshall, G. & Clark, P., 1998. A dictionary of ecology, evolution and systematics (2nd ed.). Cambridge: Cambridge University of Press.
  • McLeod, C.R., 1996. Glossary of marine ecological terms, acronyms and abbreviations used in MNCR work. In Marine Nature Conservation Review: rationale and methods, (ed. K. Hiscock), Appendix 1, pp. 93-110. Peterborough: Joint Nature Conservation Committee. [Coasts and seas of the United Kingdom, MNCR Series].