The Conchocelis-phase of Porphyra (Rhodophyta) in the intertidal of San Juan Island, Washington, USA

A simple method of assessing field abundance of the Conchocelis-phase of Porphyra (Rhodophyta) and of quantifying its abundance within invertebrate shells is described. Working in the intertidal of San Juan Island, Washington, Conchocelis filaments were found within the plates of different barnacle species. Filament density within plates decreased significantly with height on the shore. In the upper shore, filament abundance was lower and showed greater variability than at lower heights. No significant correlation was found between Conchocelis density and cover of the leafy phase of Porphyra perforata J. Agardh, a common species at the site. Results are discussed in terms of the factors that affect Conchocelis abundance and the implications of assessing methods for understanding the ecology of microscopic algal stages.