Seasonal variations in water quality of a tropical reservoir: Considerations for cage aquaculture expansion

• Main Authors: Ling, Teck Yee, Tan, Ai Chin, Nyanti, Lee, Sim, Siong Fong, Grinang, Jongkar, Lee, Karen Suan Ping, Ganyai, Tonny Anak
• Format: E-Article
• Language: English
• Published: BIOFLUX SRL 2018
• Subjects: GE Environmental Sciences
• Online Access: http://ir.unimas.my/id/eprint/20200/1/Seasonal%20variations%20in%20water%20quality%20of%20a%20tropical%20reservoir%20%28abstract0.pdf; http://ir.unimas.my/id/eprint/20200/; https://www.scopus.com/inward/record.uri?eid=2-s2.0-85045087866&partnerID=40&md5=c217e68d099c8433695552dfd67deb6b
• Institution: Universiti Malaysia Sarawak

A study of water quality of the 30 year-old Batang Ai hydroelectric reservoir at different depths and locations was conducted to give a better understanding of the water quality status for aquaculture expansion. The study was conducted at four locations where two were identified as potential cage culture sites but nearby current operations. Temperature and dissolved oxygen (DO) profilings and 13 other parameters at 0.2, 10 and 20 meters depths were also studied. It was found that the difference in DO between seasons were significant. Pockets of high nutrients and hydrogen sulphide were observed at 10 and 20 m nearby the two cage culture sites in dry season. Additionally, regardless of season, those sites showed significantly higher 10 m and 20 m suspended solids. At one of the locations near cage culture, dry season total phosphorus and ammonia were the highest at all depths and chlorophyll-a was at eutrophic level at 10 m depth. All these are attributed to aquaculture waste, pre-marketing fish processing and the lack of mixing. Water Quality Index shows that the 0.2 m depth is suitable for sensitive aquatic organism. However, dry season 10 m water column of the two potential cage culture sites was polluted. Though the cages do not normally extend to 10 m deep, when overturn occurs, it could cause fish kills. Thus, in reservoir cage culture, elimination of reservoir pre-market processing is crucial and considerations have to be made on the proximity to the current operations and dry season water quality limitations. © 2018, BIOFLUX SRL. All Rights Reserved.