ABSTRAKCochlodinium polykrikoides di kenali sebagai 'fish-killer' . Di Malaysia, spesis ini telah direkodkan di Kota Kinabalu, Sabah, Kepulauan Borneo. Setakat ini, C. polykrikoides tidak direkodkan hadir di perairan Semenanjung Malaysia. Tujuan kajian ini dijalankan adalah untuk mengenapasti kehadiran C. polykrikoides di Semenanjung Malaysia terutamanya di Tanjung Piandang, Kuala Kurau dan Kuala Gula, di perairan pesisir pantai Perak dan Selat Tebrau, Johor. Persampelan dijalankan sebanyak tiga kali di setiap stesen. Sepuluh liter sampel air laut dikutip untuk tujuan penentuan kelimpahan sel. Untuk pengecaman, fitopalnkton dikenalpasti menggunakan mikroskop cahaya. Nutrien seperti nitrat, fosfat dan ammonia di tentukan dan parameter fiziko-kimia direkodkan di tempat kajian. Berdasarkan ciri -ciri morfologi, spesis ini telah dikenalpasti sebagai C. polykrikoides. Keputusan pengiraan menunjukkan C. polykrikoides hadir dalam jumlah yang tinggi di kedua-dua Perak dan Selat Tebrau dengan kepekatan sel 2.5 x 10 3 sel/L dan 4.7 x 10 3 sel/L, masing-masing. pH, kemasinan dan suhu yang direkodkan di kedua-dua tempat adalah di dalam julat 7.68 -7.80, 27.23 -28.03 psu and 29.32 -30.90 °C, masing-masing. Tiada perbezaan bererti (P>0.05) ditemui diantara parameter fiziko-kimia dan stesen. Analisis regrasi menunjukkan tiada korelasi positif ditemui di antara kepekatan sel dan parameter fiziko-kimia dan nutrien. Kehadiaran C. polykrikoides di peraiaran Semenanjung Malaysia menunjukkan beberapa langkah pengawalan perlu diambil kira oleh agensi berkaitan memandangkan spesis ini boleh mendatangkan kesan negatif kepada industri akuakultur.The first case of harmful algal bloom (HAB) was reported in Kota Kinabalu, Sabah, East Coast of ABSTRACTCochlodinium polykrikoides is known as fish killer. In Malaysia this species has been recorded in Kota Kinabalu, Sabah, Borneo Island. To date, C. polykrikoides has not been recorded in Peninsular Malaysia. This study aims to identify the presence of C. polykrikoides in Peninsular Malaysia particularly in Tanjung Piandang, Kuala Kurau and Kuala Gula located in Perak coastal waters and Straits of Tebrau, Johor. Samplings were carried out for three times at each sampling station. Ten litre of water samples were collected for cell enumeration and identification. For identification, plankton samples were identified under light microscope. Nutrients i.e. nitrate, phosphate and ammonia were determined and physico-chemical parameters (pH, temperature, salinity) were also recorded in-situ. Species was identified as C. polykrikoides based on their morphological characteristics. Result showed that C. polykrikoides was presence in high abundance in both Perak coastal waters and Straits of Tebrau at concentration of 2.5 x 10 3 cells/L and 4.7 x 10 3 cells/L, respectively. No significant difference was found between cell abundance at these two locations. pH, salinities and temperatures recorded at both locations range between 7.68 -7.80, 27.23 -28.03 psu and 29.32 -30.90 °C, respectively. There was no si...

The high demand of seaweed for their polysaccharide namely carrageenan leads to the commercial production of carrageenophytes through mariculture. Based on literatures it is well documented that growth rate and carrageenan yield depend on environmental factors such as salinity, pH, temperatures, light intensity and water movement. In this study, growth rate and carrageenan yield of Gracilaria manilaensis, a red seaweed, was determined at different pH and salinities. G. manilaensis was cultured under laboratory conditions in a 500 mL flask at different salinities (15 psu, 20 psu and 25 psu ) and pH (7.6, 7.8, and 8.0) for 21 days. At the end of experiment, the growth rate was determined followed by carrageenan analysis. From the analysis, growth rate was highest at salinity of 15 psu and pH 7.6 with 1.3 ± 0.2 % day -1 .For carrageenan analysis, the seaweed was air dried for about a week until it reached a constant weight. Farmed G. manilaensis was used as control and carrageenan yield was determined from farmed G. manilaensis. It gives yield of 50.2 ± 10.9 %. For carrageenan yield analysis, the highest value was demonstrated at salinity of 25 psu and pH 8.0 with 91.7± 14.4 %. Result shows that carrageenan yields from G. manilaensis under laboratory conditions are higher compared to farmed Gracillaria. This indicates that the quality of G. manilaensis in term of carrageenan content can be optimized under certain growth conditions. This is important as this species has the potential to be commercialized for pharmaceutical and food industries.

Previous studies have demonstrated that the seaweed, Gracilaria manilaensis, has a high potential of producing agar for the food industry, and is a promising candidate as a dietary supplement for treating cancer and neurological disorders. Unfortunately, not many farms culturing G. manilaensis existed particularly in Malaysia. One of the reasons is limited knowledge of suitable environmental conditions needed for efficient production of the seaweed. Therefore, this study was carried out to identify the best growth conditions for G. manilaensis under different light intensities, salinities and pH. To achieve this objective, Gracilaria sp. was collected from a farm and identified based on morphological characteristics before being subjected to three environmental variables simultaneously: light intensities (100 and 1000 lux), salinities (15, 20, 25 and 30 psu) and pH (7.6, 7.8 and 8.0) simultaneously. Specific growth rates were determined for all the treatments. The results showed that G. manilaensis preferred high light intensity (1000 lux), with the growth rate of 1.69 ± 0.08 g/days at the salinity of 15 psu and pH 7.6. No significant differences were found between salinity and growth rate, indicating that G. manilaensis can tolerate a wide range of salinity. The knowledge gained from this study can be used as a guide to increasing the production of G. manilaensis in indoor farming systems. This will ensure sustainable research for G. manilaensis and production.