Interspecific competition among fouling organisms in Tomioka Bay, Japan

Abstract

Seventeen species of fouling organisms belonging to various taxonomic groups such as Ascidia, Bryozoa, sponges, Crustacea, Polychaeta and algae were observed. The results of 990 interspecific interactions among the 13 dominant species are presented in the form of a matrix, with significance of the interactions tested using the Chi-square contingency test. The hierarchical order followed the sequence ascidians > sponges > bryozoans > brown algae > barnacles > polychaetes > green algae. The main type of interaction observed during the study was overgrowth of one species by another (71.58%), while standoffs accounted for the rest. The competitive dominance followed a hierarchical order with numerous back-loops. The colonial ascidian Diplosoma mitsukurii was ranked as the most dominant species. The correlation between the area coverage of a species and the number of its interactions was highly significant. -from Authors