PertanikaJ. Trap. Agric. Sci. 16(2): 111-118 (1993) ISS : 0126-6128 © Universiti Pertanian Malaysia Press Preliminary Study of the Seagrass Flora of Sabah, Malaysia NORHADI ISMAIL Department of Marine Science Universiti Kebangsaan Malaysia (Sabah Campus), Locked Bag 62, 88996 Kota Kinabalu, Sabah, Malaysia Keywords: Seagrass, composition, distribution, biomass ABSTRAK Suatu tinjauan terhadap komposisi, taburan serta biomas beberapa dataran rumput laut yang terdapat di sepanjang pantai Sabah telah dilakukan. Di dalam tinjauan ini, sejumlah enam genera yang terdiri daripada sembilan spesies rumput laut telah direkodkan. Lima daripada spesies tersebut iaitu Cymodocea rotundata Ehrenb. et Hempr. ex Aschers., Cymodocea serrulata (R. Br.) Aschers. et Magnus, Halodule uninervis (Forssk.) Aschers., Halodule pinifolia (Miki) den Hartog dan Syringodium isoetifolium (Aschers.) Dandy yang belum pernah dilaporkan sebelum ini merupakan rekod baru bagi kawasan Sabah. Spesies yang kerap ditemui di stesen-stesen persampelan ialah Halophila ovalis (R. Br.) JD. Hook dan diikuti oleh Thalassia hemprichii (Ehrenb.) Aschers. serta Enhalus acoroides (LI) Royle. Rumput laut telah diperhatikan wujud di kawasan intertidal sehingga ke kedalaman 2.5 m dan tumbuh di atas berbagai jenis substrat seperti pecahan karang, pasir dan pasir berlumpur. Walaupun taburannya tidak menunjukkan penzonan yang spesifik, namun terdapat dua zon yang boleh dibezakan berdasarkan spesies yang paling melimpah. Dataran rumput laut di Sabah juga di dapati menghasilkan biomas yang tinggi terutamanya habitat berlumpur yang membatasi kawasan pokok bakau (contohnya biomas total E. acoroides sehingga mencapai 468.5 g berat kering tanpa abu. m· 2 ). Sementara dataran rumput laut di sekitar pulau yang di luar pantai seperti Pulau Sipadan, T. hemprichii (biomas 146 g berat kering tanpa abu. m· 2 ) didapati merupakan pengeluar biomas yang utama. ABSTRACT The species composition, distribution and the biomass of different seagrass beds along the coast of Sabah have been surveyed. Nine seagrass species belonging to six genera were recorded during the survey. Five of these i. e Cymodocea rotundata Ehrenb. et Hempr. ex Aschers., Cymodocea serrulata (R. Br.) Aschers. et Magnus, Halodule uninervis (Forssk.) Aschers., Halodule pinifolia (Miki) den Hartog and Syringodium isoetifolium (Aschers.) Dandy have not previously been reported from this area, thus represent new records for Sabah. The most frequently encountered species at the sampling stations was Halophila oval is (R. Br.) JD. Hook followed by Thalassia hemprichii (Ehrenb.) Aschers and Enhalus acoroides (L.f) Royle. Seagrasses were observed from intertidal zone down to 2.5 m depth on various substrate types such as coral rubble, sand to muddy-sand. There was no specific zonation in the distribution of seagrasses. However, two zones may be distinguished according to the most abundant species. The seagrass beds in Sabah were also found to produce very high biomass particularly in the muddy habitat bordering mangroves (e.g. total biomass E. acoroides amounted to 468.5 g AFDW m· 2 ). Among the seagrass beds around the off-shore islands such as Pulau Sipadan, T. hemprichii (146 g AFDW m· 2 ) was found to be a very important biomass contributor. INTRODUCTION At least nine species of seagrasses are found in Malaysian waters (Fortes 1990). While informa- tion regarding recent local records of seagrass are available for the Malaysian Peninsula (phang and Pubalan 1989), knowledge of the seagrasses in Sabah, however, is almost exclusively from the three previously reported species of Halophila ovalis (R. Br.) Hook. f., Thalassia hemprichii (Ehrenb.) Aschers. and Enhalus acoroides (L.f) Royle (den Hartog 1970) collected from Labuan, Sandakan and Lahad Datu. Furthermore, no