The effects of seasonal and shore height on the growth and reproduction of Chondrus ocellatus were examined in the low intertidal zone of Hakampo, Korea from July 2014 to April 2015. Seasonal biomass, density, frond weight and G:T ratio of C. ocellatus was examined at upper and lower shore height of Chondrus zone. We hypothesized that, (1) growth and reproductive fronds of C. ocellatus are increased at the lower shore, having less environmental stress over the study period, (2) carposporophytes and gametophytes are dominant at upper shore as do many Gigartinaceae species, and (3) the G:T ratio of C. ocellatus are changeable in season and shore height. Biomass and frond weight were significantly greater in lower shore than upper shore and differences were also found between the seasons with the highest biomass (1695.82 g wet wt./m2)in July and frond weight (797.27mg)October. However, frond densities were not significantly different between seasons and shore heights. Carposporophytes including gametophytes were dominant at up pershore, whereas tetrasporophytes were abundant at the lower shore, even in the C. ocellatus zone. Seasonal reproductive patterns in the percentage of tetrasporophytes and carposporophytes were very similar with maximal in October and minimal in April. However, tetrasporophytes were more abundant than carposporophytes during the study period. The G:T ratio in C. ocellatus was ranged from 0.05 to 2.45 and it was significantly different between the seasons and shore heights. We conclude that environmental stresses induced by tidal cycle in the intertidal area are determinant in the abundance and reproduction status of C. ocellatus. At Hakampo shore, C. ocellatus has growth period between July-October and reproduction period in October and January.

• Cyr Abel Maranguy Ogandaga(원광대학교 생물학과)
• Jung Rok Lee(원광대학교 생물학과)
• Han Gil Choi(원광대학교 생물학과)