• Journal of Fisheries and Marine Sciences Education
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• v.28 no.3
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• pp.746-759
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• 2016

In this study, we monitored the status of marine environment of olive flounder, Paralichythys olivaceus, culture ground in Jeju-do, Republic of Korea. It reported the consumption of raw olive flounder meat containing of Kudoa, Kudoa septempunctata, could induce vomitting and diarrhea in Japan. The Kudoa is a new mycosporean species, researchers found Kudoa from the muscles of olive flounder cultured at western Japan and imported from Jeju-do. We choose two Kudoa positive farms and two negative farms in the mid of concern about the relation between Kudoa and habitat. We found two marine invasive species at the water-pumping seabed at one of the Kudoa positive farm. The concentration of pH and DO at on-growing flounder farms showed the decreasing pattern along side the raceway (influent sea waters > on growing sea waters > outfluent sea waters). The TN and TP values increased gradually following to the raceway (influent sea waters < on growing sea waters < outfluent sea waters). The concentration of COD and SS were in the range of $0.100-2.581mg{\cdot}L^{-1}$, $1.00-12.70mg{\cdot}L^{-1}$, respectively. The calculated residence time was 4hr 32minutes at F1, 11hr 21minutes at F2, and 9hr 50minutes at F3, respectively. It was calculated same distance of 4 km away from effluent pipes. Although direct relation between Kudoa and marine environment could not define well based on this study result, the more studies on marine environmental stressors for olive flounder are required to conduct as a reliable method including socio-economic group and environmental group.

• Journal of Aquaculture
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• v.19 no.2
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• pp.133-139
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• 2006

The gossypol existed in cottonseed meal is a well known antispermatogenic agent which can impair reproductive performances of male fish as well as mammals. Two feeding experiments were conducted to examine a toxic effect of dietary supplementation of cottonseed meal on reproduction in juvenile olive flounder (the first experiment) for 19 weeks and growing olive flounder (the second experiment) for 26 weeks. After each feeding study, females and males were sampled for histological examination in gonads and liver to verify any negative effects by the dietary supplementation of cottonseed and soybean meal on reproduction. After two feeding trial, the gonad somatic index (GSI) of male and female (from the first feeding trial) were not significantly different among all the dietary treatments. The GSI values of female (from the second feeding trial) were not significantly different among all the dietary treatments. However, males fed cottonseed and soybean meal containing diets exhibited significantly lower GSI than that fed the control diet after the second feeding trial. Histological examination of gonads and liver of fish fed cottonseed and soybean meal did not show any negative effects compared to those of fish ffd the control diet. Hepatosomatic index of fish in the first and second feeding trials were not significantly different among all the dietary treatments. The findings in this study suggest that dietary supplementation of cottonseed and soybean meal up to 40% fish meal replacement might not deteriorate the gametogenesis of juvenile and growing olive flounder. However, the supplementation in diets over 30% fish meal replacement might reduce GSI of male in growing olive flounder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.3
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• pp.464-470
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• 2020

This study was conducted to replace fish meal (FM) with three plant proteins (soybean meal, soy protein concentrate, and wheat gluten) in diets for growing olive flounder Paralichthys olivaceus. The control diet was formulated to contain 65% sardine FM and four other replacement diets were formulated to replace FM with the plant proteins by 25, 30, 35 and 40% (designated FM25, FM30, FM35 and FM40, respectively). The replacement diets were added with three essential amino acids (lysine, methionine and threonine) to meet their requirements for the fish. Olive flounder (initial average weight, 96.8±0.2 g) were randomly distributed into 20 tanks (425 L each) at a density of 25 fish per tank. Four replicate groups of fish were fed one of the diets two times daily for 15 weeks. At the end of the feeding trial, no significant differences were found among all the fish groups in growth performance, feed utilization, nonspecific immune responses and hematological health parameters. Thus, this result indicates that the plant proteins with the three limiting amino acids could replace FM up to 40% in diets for growing olive flounder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.681-687
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• 2015

We investigated the effects of feeding rate on the growth performance of growing and sub-adult olive flounder Paralichthys olivaceus, and the optimum feeding rate at high water temperature (25-31℃). In experiment I, two replicated groups of fish (113 g) were fed a commercial diet (CD) at rates of 0, 0.7, 1.2, 1.7, 2.2, and 2.4% (satiation) body weight (BW) per day for 4 weeks. In experiment II, two replicated groups of fish (313 g) were fed a CD feeding rates of 0, 0.3, 0.5, 0.7, 0.9, and 1.0% (satiation) BW per day for 4 weeks. In experiment I, the weight gain (WG) and specific growth rate (SGR) of fish fed at 0.7 and 0.9% BW per day was significantly higher than that of unfed fish (0%) and fish fed at 0.3, 0.5, and 1.0% (satiation) BW per day. In experiment II, the WG and SGR increased significantly as feeding rate increased from 0 to 2.2% BW per day, but decreased in the satiation group (2.4%). Broken-line regression analysis of WG showed that the optimum feeding rate of growing and sub-adult olive flounder were 1.98% and 0.55% BW per day, respectively, at the high water temperature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.557-561
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• 2010

This feeding experiment was conducted to investigate the effects of dietary inclusion of some additives on growth performance, hematological parameter and fatty acid composition of growing flounder. Triplicate groups of fish (average weight 120 g) were fed one of five diets containing 5% kelp meal (Ke), 10% krill meal (Kr), 1% garlic powder (Ga), 1% citrus meal (Ci) or control diet (Con) without supplementation for 15 weeks. After the feeding experiment, survival was not significantly different among the groups fed the different diets. Weight gain of fish fed the Ci diet was significantly higher than that of fish fed the Kr diet, but not significantly different from Con, Ke and Ga treatments. Feed efficiency and protein efficiency ratio of fish fed the Ga diet were significantly higher than those of fish fed the other diets. Total protein, glucose, GOT, GPT and total cholesterol contents in the plasma were not affected by the dietary additives. Composition of C20:4n-6 in the dorsal muscle of fish fed the Con diet was significantly higher than that of fish fed the other diets. The results of this study suggest that the dietary inclusion of garlic meal at 1% may improve feed utilization of growing flounder.

• Fisheries and Aquatic Sciences
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• v.17 no.4
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• pp.391-401
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• 2014

Ten feeding trials were conducted to determine and to make the guideline for the optimum feeding rates in olive flounder Paralichthys olivaceus fed extruded pellets at various growth stages at the optimum rearing water temperature. The entire trials were grouped into four growth stages, namely the first stage of juvenile (5 and 9 g), the second stage of juvenile (20, 30, 40 and 50 g), growing (240 and 317 g) and sub-adult (384 and 525 g) stages with 2, 4, 2 and 2 feeding trials, respectively. In the first and second experiments, results indicated that the optimum feeding rates for the first stage of juvenile olive flounder weighing 5 and 9 g could be >5.17 but <5.52% and >4.44 but <4.64% body weight (BW)/day, respectively. In the third, fourth, fifth and sixth experiments, results suggested that the optimum feeding rates for the second stage of juvenile olive flounder weighing 20, 30, 40 and 50 g could be >3.47 but <3.50, >2.85 but <3.53, >2.58 but <3.04 and >2.36 but <2.50% BW/day, respectively. In the seventh and eighth experiments, results showed the optimum feeding rates for growing olive flounder weighing 240 and 317 g to be >1.03 but <1.25 and >0.85 but <1.0 % BW/day, respectively. In the ninth and tenth experiments, the optimum feeding rates in sub-adult olive flounder weighing 384 and 525 g were shown to be >0.69 but <0.7 and >0.55 but <0.8% BW/day, respectively. We will compare these results with the previous studies done by other research groups.

• Environmental Analysis Health and Toxicology
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• v.17 no.1
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• pp.13-19
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• 2002

Effects of Formalin treatment on embryogenesis and larvae growing in fertilized eggs and hatched larvae of olive flounder, Paralichthys alivaceus were investigated. Fertilized eggs and hatched larvae were exposed to aqueous solution with 100, 200, 400, 800 and 1,000 ppm of nominal formalin concentration. They were kept in sea water of 16, 18 and 22$^{\circ}C$, respectively. Survival rate and hatchability of fertilized eggs were high in control groups more than formalin treated groups in 16, 18 and 22$^{\circ}C$, respectively (P<0.05). A similar effect that survival rate of hatched larvae was also observed for control and treatment groups. On the other hand, fertilized eggs treated with 400 ppm formalin, were all death in kept in 22$^{\circ}C$. These results suggest that high-dose of formalin in fertilized eggs and hatched larvae in olive flounder, Paralichthys olivaceus was inhibited the normal embryogenesis for fertilized eggs and growing for hatched larvae. Also, these inhibited effects was promoted in higher temperature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.1
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• pp.109-115
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• 2023

Interspecific hybridization is a beneficial strategy in aquaculture. In this study, diploid hybrids were produced through interspecies hybridization of flounder Platichthys bicoloratus ♀ × starry flounder P. stellatus ♂, which became commercial within a year. These hybrids exhibited an advantage in growth ability, with female hybrids growing twice as large as males at 11 months. Furthermore, hybrid flounders exhibited faster growth rates than starry flounders and reciprocal hybrids. The average growth rate of hybrids was 1.37 and 1.18 times greater than that of starry flounder and reciprocal hybrids at 5.5 months, respectively; Additionally, feed efficiency was 1.21 and 1.10 times higher than that of the experimental groups. The experiments were conducted at five temperatures to determine the optimal fry production method. Six weeks of culture resulted in a significant temperature effect, with maximum growth at 27℃. However, over 90% of the males occurred in the groups at temperatures above 24℃. Therefore, the optimum temperatures for survival, growth, condition factor and frequency of the best-sized fingerling at 13 weeks of age were estimated at 21℃. Thus, hybrid flounders are of great potential for use in the flounder aquaculture industry.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.5
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• pp.523-526
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• 2012

This study evaluated the effects of the number of feeding days and feeding rate on the growth of growing-out flounder Paralichthys olivaceus. Three replicated groups of fish ($141{\pm}1.9g$) were hand-fed a commercial feed under different feeding regimes for 9 weeks. Fish in group 6F-1S were fed to satiation twice daily for 6 consecutive days and starved for 1 day. Fish in groups 4F-1S and 3F-1S were fed to satiation twice daily for 4 and 3 days, respectively, and starved for 1 day. Fish in group 6F-90% were fed a diet of 90% of 6F-1S twice daily for 6 consecutive days and starved for 1 day. The weight gain, feed efficiency and daily feed intake of the fish groups in 4F-1S and 3F-1S were not significantly different from those of group 6F-1S. The weight gain and feed efficiency of fish in group 6F-90% were not significantly different from those of group 6F-1S. The results of this study suggest that the growth of growing-out flounder fed to satiation twice daily for 4 or 3 days after starving 1 day was similar to that of fish fed to satiation for 6 days, and that the proper feeding rate for growth could be lowered to 90% of satiation without growth suppression.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.4
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• pp.789-796
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• 2014

This study was conducted to investigate the effects of feeding rate on growth performance, blood components and histology of growing olive flounder. The experiment was carried out to determine the optimum feeding rate of the fish (initial fish mean weight of $97{\pm}3.0$ g) at the optimum water temperature. Two replicated groups of fish were fed commercial diet at the feeding rates of 0, 1.0, 1.65 and 2.3% body weight (BW)/day and satiation. Feeding trial was conducted under a flow-through system with ten 1.2 metric ton aquaria receiving filtered seawater at $21{\pm}2^{\circ}C$ for three weeks. Weight gain and specific growth rate (SGR) for fish fed to satiation were significantly higher than those for the unfed fish and for fish fed at 1.0 and 1.65% BW/day. There were no significant differences in values of such parameters between fish fed at 1.65% and those fed at 2.3% BW/day and between fish fed at 2.3% and those fed to satiation. Weight gain and SGR for the unfed fish were significantly lower than those for fish in the other treatments. All the tissues (hepatopancreas, kidney and anterior intestine) were in good condition in fish fed the experimental diet at different feeding rates. This result indicates that the optimum feeding rates of olive flounder (97-160 g) was approximately 2.52% BW/day at the optimum water temperature.