The phytal fish fauna of Cystophora torulosa, - scalaris, . congesta and Carpophyllum maschalocarpum forming the subtidal fringe at Wairepo Flats, Kaikoura was investigated over a period of fifteen months from 26 March 1987 to 1 June 1988. The phytal assemblage was dominated by Notolabrus celidotus, Notoclinus compressus, Ericentrus ruber, Forsterygion capita, Gastrocyathus gracilis and Gastroscyphus hectoris. N. celidotus, E. ruber and F. capita used fringing macroalgae as a nursery habitat. N. compressus, G. gracilis and G. hectoris were resident phytophilic species. All species, except N. compressus, exhibited large fluctuations in density that were correlated with the seasonal temperature regime. All were dependent on seasonal recruitment for persistence in the study site. The juveniles of most species settled into the study site from the plankton but those of G. gracilis migrated into the study site from the adjacent subtidal following settlement failure in the study site in January 1988.

Despite large population fluctuations species diversity, species composition and distribution were predictable throughout the study. All species had a preferred but for N. celidotus and N, compressus this changed with size. These preferences were correlated with algal complexity, and the morphology of the feeding structures of the fish. Algal morphology and appeared to be more important than interspecific interactions, such as competition, in maintaining assemblage structure.