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Gunzo Kawamura,Teodora Bagarinao,Annita Seok Kian Yong,Chiau Yu Chen,Siti Norasidah Mat Noor,Leong Seng Lim 한국해양과학기술원 2015 Ocean science journal Vol.50 No.2
Acidification of rain water caused by air pollutants is now recognized as a serious threat to aquatic ecosystems. We examined the effects of low pH (control pH 7.5, pH 6, pH 5, pH 4) on the survival, growth, and shell quality of Macrobrachium rosenbergii postlarvae and early juveniles in the laboratory. Hatcheryproduced postlarvae (PL 5) were stocked at 250 PL per aquarium, acclimated over 7 d to experimental pH adjusted with hydrochloric acid, and reared for 30 d. Dead specimens were removed and counted twice a day. After 27 d rearing, all specimens were measured for total length and body weight. Carapace quality was assessed by spectrophotometry. Survival of juveniles was highest at pH 6 (binomial 95% confidence interval 79 - 89%) followed by control pH 7.5 (56 - 68%) and pH 5 (50 - 60%) and was lowest for unmetamorphosed postlarvae and juveniles at pH 4 (43 - 49%). The final median total length and body weight of juveniles were similar at control pH 7.5 (18.2 TL, 50.2 mg BW) and pH 6 (17.7 mm TL, 45.0 mg BW) but significantly less at pH 5 (16.7 mm TL, 38.2 mg BW); at pH 4, the postlarvae did not metamorphose and measured only 9.8 mm TL, 29.3 mg BW. Length frequency distribution showed homogeneous growth at pH 6, positive skew at control pH 7.5 and pH 5, and extreme heterogeneity at pH 4. The carapace showed different transmittance spectra and lower total transmittance (i.e. thicker carapace) in juveniles at pH 7.5, pH 6, and pH 5 than in unmetamorphosed postlarvae and juveniles with thinner carapace at pH 4. Thus, survival, growth, size distribution, and carapace quality of M. rosenbergii postlarvae and early juveniles were negatively affected by pH 5 and especially pH 4. The thinner carapace of the survivors at pH 4 was mostly due to their small size and failure to metamorphose. Natural waters affected by acid rain could decimate M. rosenbergii populations in the wild.
( Yang Su Kim ),( Seung Cheol Ji ),( Amal Biswas ),( Biswajit Kumar Biswas ),( Annita Seok Kian Yong ),( Osamu Takaoka ),( Gwan Sik Jeong ),( Osamu Murata ),( Kenji Takii ) 한국수산과학회(구 한국수산학회) 2014 Fisheries and Aquatic Sciences Vol.17 No.1
To determine a suitable dietary protein/lipid (CP/CL) ratio in the early juvenile stages of hybrid porgy (F1), female red sea bream (RSB) × male black sea bream, five diets with various CP/CL ratios「60/7, 55/12, 51/17, 46/23, and 41/28」were prepared and provided to juveniles in triplicate. At the smaller juvenile stage, F1, weighing 0.32 g, a significantly higher specific growth rate (SGR) and feed efficiency (FE) were seen with 60/7 and 55/12 diets. However, in RSB weighing 0.26 g, SGR and FE were higher with the 60/7 diet than the other diets at 21°C. At the larger juvenile stage, F1, weighing 3.7 g, there was no significant difference in SGR or FE among the diets, but RSB weighing 4.0 g fed 60/7, 55/12, and 51/17 diets had higher SGR and FE than 46/23 and 41/28 diets at 24°C. Moreover, survival and apparent nutrient retention of F1 at both stages were significantly higher than those in RSB. These results indicate that both F1 and RSB weighing ca. 0.3 g require a higher dietary CP/CL than those weighing ca. 4 g. Additionally, F1 in both trials showed the suitability of a lower dietary CP/CL than RSB, indicating that mass production of F1 juveniles will be more economical than RSB.
Kim, Yang-Su,Ji, Seung-Cheol,Biswas, Amal,Biswas, Biswajit Kumar,Yong, Annita Seok Kian,Takaoka, Osamu,Jeong, Gwan-Sik,Murata, Osamu,Takii, Kenji The Korean Society of Fisheries and Aquatic Scienc 2014 Fisheries and Aquatic Sciences Vol.17 No.1
To determine a suitable dietary protein/lipid (CP/CL) ratio in the early juvenile stages of hybrid porgy ($F_1$), female red sea bream (RSB) ${\times}$ male black sea bream, five diets with various CP/CL ratios-60/7, 55/12, 51/17, 46/23, and 41/28-were prepared and provided to juveniles in triplicate. At the smaller juvenile stage, $F_1$, weighing 0.32 g, a significantly higher specific growth rate (SGR) and feed efficiency (FE) were seen with 60/7 and 55/12 diets. However, in RSB weighing 0.26 g, SGR and FE were higher with the 60/7 diet than the other diets at $21^{\circ}C$. At the larger juvenile stage, $F_1$, weighing 3.7 g, there was no significant difference in SGR or FE among the diets, but RSB weighing 4.0 g fed 60/7, 55/12, and 51/17 diets had higher SGR and FE than 46/23 and 41/28 diets at $24^{\circ}C$. Moreover, survival and apparent nutrient retention of $F_1$ at both stages were significantly higher than those in RSB. These results indicate that both $F_1$ and RSB weighing ca. 0.3 g require a higher dietary CP/CL than those weighing ca. 4 g. Additionally, $F_1$ in both trials showed the suitability of a lower dietary CP/CL than RSB, indicating that mass production of $F_1$ juveniles will be more economical than RSB.