Biomass and reproductive states of Gracilaria heteroclada Zhang et Xia collected from Jaro, central Philippines

Abstract

Biomass production and reproductive states were investigated to determine the abundance of Gracilaria heteroclada Zhang et Xia at Jaro, central Philippines from March 1990 to February 1991. Biomass of Gracilaria heteroclada was highest in February (45 g/m²) and lowest in July (1.16 g/m²). Plant fertility was seasonal with the highest percentage of carposporphytic and tetrasporophytic plants occurring in January (48%) and in May (64%) respectively. Seawater temperature was significantly correlated with tetrasporophyte occurrence (r = 0.6586) but not with carposporophyte occurrence. There was no correlation of the occurrence of tetrasporophytes or carposporophytes with salinity or rainfall.