Ecological studies ofGracilaria asiatica andGracilaria lemaneiformis in Zhanshan Bay,Qingdao

Natural populations ofG. asiatica Zhang & Xia andG. lemaneiformis (Bory) Weber van Bosse were studied during 1984 and 1986 in Zhanshan Bay, Qingdao (36°4'N, 120° 21'E). Rapid growth (length, weight) of these plants occurred between mid-May and late June (water temperatures, 15–20°C). The major epiphyte ofG. asiatica wasEnteromorpha linza, whilePunctaria latifolia was the major epiphyte ofG. lemaneiformis. Epiphytism declined throughout early summer, and epiphytes were rare after mid-July (1984); they did not reappear in late summer, although macrophyte growth declined abruptly after early July. Populations ofG. asiatica varied during late spring-early summer between adjacent sandy and rocky portions of the intertidal zone; plants at the sandy site were larger and epiphyte-free. Amphipod densities were low on both species ofGracilaria, but the most abundant species wereAmpithoe lacertosa, Caprella equilibra, C. krøyeri, C. scauraandPontogeneia rostrata. Additional information on general community structure is provided for theG. asiatica zone.