Aeration rate adjustment at night to prevent sinking syndrome‐related death in the tiger grouper Epinephelus fuscoguttatus (Perciformes:Serranidae) larvae |
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| Authors: | Ching Fui Fui Akira Miura Yoshizumi Nakagawa Keitaro Kato Wataru Sakamoto Kenji Takii Shigeru Miyashita Shigeharu Senoo |
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| Institution: | 1. Borneo Marine Research Institute, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia;2. Department of Fisheries, Graduate School of Agriculture, Kinki University, Nara, Japan;3. Department of Aqua Bioscience and Industry, Faculty of Bioindustry, Tokyo University of Agriculture, Hokkaido, Japan;4. Fisheries Laboratory, Kinki University, Shirahama, Wakayama, Japan;5. Fisheries Laboratory, Kinki University, Uragami, Wakayama, Japan |
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| Abstract: | The effects of different aeration rates at night to prevent sinking syndrome‐related death (SSRD) of the tiger grouper, Epinephelus fuscoguttatus were examined. The aeration rates were fixed at 300 mL min?1 at daytime (07:00–19:00 hours) and regulated to 0, 300 and 900 mL min?1 at night (19:00–07:00 hours). Larval survival, growth, feeding intake, sinking velocity, distribution and behaviour, stress level, surface tension‐related death (STRD) and flow velocity distribution were assessed. The occurrence of SSRD in the tiger grouper was observed through the accelerated sinking velocity (Vl) (from 0.15 ± 0.09 cm s?1 at 4 days AH to 0.41 ± 0.09 cm s?1 at 12 days AH) coupled with larval passive swimming behaviour at night‐time. On the final day of experiment (15 days AH), larvae reared in 900 mL min?1 at night had attained significantly higher (P < 0.05) survival (34.4 ± 5.5%), growth (5.8 ± 0.5 mm) and feeding intake (60.46 ± 6.98 ind. larva?1). A favourable flow field for the tiger grouper was produced in 900 mL min?1 at night‐time, in which larvae were transported 15–25 cm above the tank bottom and 1.0 cm beneath the water surface. Under these night‐time rearing conditions, larval stress level and number of STRD reared in 900 mL min?1 compared with those observed in 300 mL min?1 remained insignificant, indicating that strong turbulence of flow velocity was not detrimental for larvae. Our findings recommend aeration at 900 mL min?1 at night as this could improve larval survival by reducing SSRD. |
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| Keywords: | aeration rate adjustment sinking syndrome‐related death survival flow field
Epinephelus fuscoguttatus
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