GROWTH AND ORGANIC PRODUCTION OF EELGRASS (ZOSTERA-MARINA L) IN TEMPERATE WATERS OF THE PACIFIC COAST OF JAPAN .1. GROWTH ANALYSIS IN SPRING-SUMMER

The mode and dynamics of the growth of eelgrass (Zostera marina L.) in Nabeta Bay, Japan, were investigated in a culture experiment in April-June. Two types of vegetative growth, that is, leaf elongation and new lateral shoot production, were distinguished. Formation of new leaves and defoliation were apparently synchronized, and numbers of leaves on a single vegetative shoot remained almost constant (5.5 ± 0.1). Maximum growth occurred in May. Generative (flowering) shoots were produced in May-June, and seed maturation was completed by the end of June. Mean life times of leaves on vegetative and generative shoots were 43.6 ± 1.0 and 38.7 ± 1.4 days, respectively. Net organic production by eelgrass in Nabeta Bay in June was estimated to be 7.2 g dry wt-2 day-1. © 1979.