Pencemaran lingkungan oleh limbah organik mengandung nitrogen (N) dan fosfat (P) yang bersumber dari tambak udang superintensif karena penggunaan pakan yang banyak merupakan masalah serius dalam pengembangan teknologi superintensif di Indonesia. Penelitian ini bertujuan untuk mengestimasi jumlah pakan yang terbuang ke lingkungan selama budidaya di tambak superintensifdan untuk mengestimasi jumlah limbah N dan P yang terbuang ke lingkungan dari kegiatan budidaya superintensif. Metode penelitian dilakukan sebanyak 3 tahap; tahap pertama dilakukan pada tambak superintensif selama 76 hari dengan melakukan budidaya udang superintensif dengan kepadatan 600 ekor/m2 selanjutnya dilakukan pengamatan pakan yang terbuang. Tahap kedua adalah melakukan uji kecernaan udang skala laboratorium dan tahap ketiga adalah penelitian ekskresi udang skala laboratorium. Hasil penelitian menunjukkan bahwa jumlah pakan tidak termakan yang terbuang ke lingkungan dari tambak superintensif sebesar 24,32% dari total pakan yang digunakan. Beban limbah organik dari tambak udang superintensif yang terbuang ke perairan Teluk Labuange sebesar 3,89 ton terdiri dari limbah organik mengandung N sebesar 3,61 ton/tahun dengan rerata buangan ke perairan 10,31 kg/hari, dan limbah organik mengandung P sebesar 0,28 ton/tahun dengan rerata buangan ke perairan 0,81 kg/hari. Hasil ini menunjukkan bahwa perairan Teluk Labuange telah mengalami tekanan limbah organik yang berasal dari kegiatan tambak udang superintensif.
This research series consisted of 4 (four) research activities, two implemented indoors at the Center for Brackishwater Aquaculture (BPBAP) Takalar in July - August 2017, and two carried out in the coastal waters of Aeng Batu-Batu Village, Galesong District, Takalar Regency, South Sulawesi, Indonesia in May - July 2018. The objectives of the studies were to analyse growth and content of specific nutritional components (carotenoids, fibre, and minerals) of the seaweed Caulerpa lentillifera. The C. lentillifera cultivated indoors and in coastal waters had the same cultivation period and initial seedling weight. There were differences in C. lentillifera growth and nutritional content between the two treatments. Growth and mineral content were higher indoors; likely due to the presence of readily absorbed minerals in the substrate provided (a mixture of sand and coral fragments). Higher carotenoid and fibre content in C. lentillifera cultivated in coastal waters was likely due to carotenoid synthesis by the seaweed to protect chlorophyll from damage, and increased photosynthesis producing more complex carbohydrates (fibre). Although lower than in some previous studies, the mineral and fibre content of C. lentillifera in both treatments was higher than the levels found in most land plants seaweeds.
The way to prevent or treating bacterial diseases outbreaks with drugs or chemicals is the one of main solutions to solve the problems in aquaculture. The use of antibacterial agents has increased significantly in aquaculture practices, since the antibiotics used in both human as well as veterinary medicines have been tried experimentally to treat bacterial infections of fish. However, the evolving resistance of fish pathogenic bacteria to existing antibiotics has necessitated development of new alternatives. In the last three decades the discovery of metabolites with biological activities from algae has increased significantly. In this study, sixteen extracts from four algae of genus Eucheuma were tested by in-vitro against five pathogenic bacteria (Aeromonas salmonicida, Aeromonas hydrophila, Pseudomonas anguilliseptica, Vibrio anguillarum and Yersinia ruckeri). The algae were extracted in Soxhlet apparatus using solvents with increased polarity (hexane, dichloromethane, methanol and water) for 24 h. The extract solutions were then evaporated and liophilized before using for the antibacterial test with agar diffusion method. The results revealed that three of four extracts (hexane, dichloromethane and water) were active against all pathogens, while methanol did not. The highest activity was shown by water extract, followed by the hexane and the dichloromethane extracts with lower activities. The water extract of Eucheuma spinosum had a broad activity since it was active against four of five pathogenic strains. Vibrio anguillarum and Pseudomonas anguillaseptica were the two most susceptible pathogens, while the most resistant was presented by Aeromonas hydrophila. The screening results confirm that algae were potential to be developed as a source of antibacterial compounds or as a health-promoting food for aquaculture.
This study aimed to evaluate the growth and yield of carrageenan from Kappaphycus alvarezii (Doty) cultured at different depths of water. The study lasted for 49 days, using two strains (green and brown), three initial weights (50, 100, 150 g), and five levels of depth (1, 2½, 4, 5½, 7 m). The results showed significant differences between growth rate and yield of carrageenan on the three treatments (P<0.01). The highest growth rate of both morphology types of green and brown occur on the same weight and depth i.e., at initial weight 100 g and depth 2½ m, respectively at 5.68 and 6.05%/day. The yield of carrageenan is likely to increase in depth with the highest value at a depth of 7 m, respectively 17.12% at green type and 14.63% at brown type. The results showed that reducing growth may increase the yield of carrageenan by the increasing of water depth. Based on these results, this study can be applied to another location as long as the quality of water allows farming activities.
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