The importance of substrate type in colonization by Cryptonemia hibernica Guiry et Irvine and its associated algae

Summary The study showed not only that Cryptonemia hibernica colonized all thirteen substrate classes, but also that in each substrate class its colonization success rate was higher than that of any of the other macroalgae present. C. hibernica not only grew on all classes of rock, boulders and shells and as an algal epiphyte but also was found on live barnacles, scallops and razor shells. C. hibernica appears to be capable of growing in a variety of environmental conditions as illustrated by the five sites studied and can exploit a very wide range of substrates. These would appear to be important factors in the successful spread of C. hibernica. Its distribution in Cork Harbour and Kinsale Harbour is possibly curtailed only by depth and/or the occurrence of sand or mud substrate.