The yield and quality of agar from Gracilaria species collected from distinct natural habitats (mangrove
swamp, rocky shore, sandy mudflat) along the west coast of Peninsular Malaysia were evaluated in this
study. The agar content was found to be significantly higher in G. changii and G. edulis growing in the
mangrove swamp, while the lowest agar content was recorded for G. changii and G. edulis collected from
the sandy mudflat. Higher agar gel strength was obtained from the three Gracilaria species collected
from the mangrove swamp compared to those that live in the sandy mudflat and rocky shore. The
intraspecific variations found in gelling temperature were well correlated with the trend of changes in
agar gel strength, except for G. changii collected from the sandy mudflat and rocky shore. The intraspecific
and interspecific variations of agar melting temperature did not show a consistent trend for all Gracilaria
species tested. The agars of Gracilaria spp. collected from the rocky shore showed a significantly higher
gel syneresis while the lowest gel syneresis was recorded for the agars of samples collected from the
mangrove swamp, except for the agars of G. salicornia from different habitats which showed no difference.
In conclusion, the mangrove swamp is a natural habitat which produces Gracilaria with good agar
properties, in terms of agar yield, gel strength and gel hysteresis, thus it can be considered as a potential
site for seaweed farming and mariculture for the agar industry in Malaysia.