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


Host An organsim that provides food or shelter for another organisms, e.g.  the inhabited symbiont. May be a defintive host infected by an adult stage or an intermediate host infected by life stages (see Lincoln et al., 1998). 
Substratum An organism that provide unique substratum for specific other organisms, rarely found on other organisms.