• Korean Journal of Ichthyology
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• v.29 no.1
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• pp.13-21
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• 2017

We investigated that changes of survival rate and hematological factors in sevenband grouper (Epinephelus septemfasciatus), exposed to ammonia. First, the fish was exposed and was observed survival rate. We observed the survival rate of the fish when exposed at each ammonia concentrations (0, 0.35, 0.4, 0.5, 0.8 mg/L, $NH_3$) for 96 hours. The 96-h $LC_{50}$ (lethal ambient concentration for 50% of the population) of $NH_4^+$ and un-ionized ammonia ($NH_3$) for sevenband grouper were 26.7 and 0.6 mg/L, respectively. Secondly, we exposed the fish to 96-h $LC_{50}$ ammonia concentration (0.6 mg/L) for 96 hours, then sampled the blood of groupers for analysis of cortisol, glucose, $NH_3$, GOT, GPT, total protein (TP), electrolytes ($Na^+$, $Cl^-$) and osmolality in plasma. The plasma cortisol, glucose, GOT and GPT were increased with increasing of elapsed time and ammonia concentration. In addition, the $NH_3$ and total protein in plasma were significantly increased to 12 hours exposed to ammonia, and then decreased. But, the values were significantly higher than the control. The plasma electrolytes ($Na^+$, $Cl^-$) and osmolality were decreased with increasing of elasped time. The results in the present study suggest that the continuous exposure of ammonia to juveniles of sevenband grouper may be a stressor and negative influence.

• Journal of Aquaculture
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• v.14 no.1
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• pp.1-7
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• 2001

Global status of aquaculture and aquaculture scientific journals is briefly described. Asia is the centre of fishing and aquaculture activities but most publishers, editors and editorial board members of fisheries and aquaculture journals are from Europe and/or USA. The contribution by Asian fisheries/aquaculture scientists to these journals remains low. Language barrier and requirement for monitory investment seem to inhibit Asian participation in this realm of scientific activity. The need for glob-alization of aquaculture scientific journals is emphasized. Selected strategies, which are adopted by the Western journals to improve their image and management, are indicated.

• The Journal of Fisheries Business Administration
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• v.49 no.4
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• pp.19-36
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• 2018

Overstock in aquaculture is a matter of concern in aquaculture management. To sort fish based on fingerling size in case of overstocking is an important problem in aquaculture farm. This study aims to determine the amount of fry overstock and sorting time in aquaculture farm. This study builds a mathematical model that finds the value of decision variables to optimize objective function summing up the fingerling purchasing cost, aquaculture farm operating cost and feeding cost under mortality and farming period constraints. The proposed mathematical model involves following biological and economical variables and coefficients: (1) number of fingerlings, (2) sorting time, (3) fish growth rate and variation, (4) mortality, (5) price of a fry (6) feeding cost, and (7) possible sorting periods. Numerical simulation is presented herein. The objective of numerical simulation is to provide decision makers to analyse and comprehend the proposed model. When extensive biological data about growth function of fry becomes available, the proposed model can be widely applicable to real aquaculture farms.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.575-581
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• 2013

We examined the effect of starvation on the occurrence of tunic softness to determine the cause of mass mortality of cultured Halocynthia roretzi (Drasche) in the Tongyeong region, Korea. In terms of the survival rate of H. roretzi and the occurrence rate of tunic softness, H. roretzi starved for 35 days at water temperatures of 8, 12, and $15^{\circ}C{\pm}0.5^{\circ}C$ (room temperature of $15^{\circ}C{\pm}1^{\circ}C$) did not exhibit tunic softness at water temperatures of either $8^{\circ}C$ or $12^{\circ}C$. for morphological changes, although the tunic of H. roretzi was shrunken and became visibly smaller with a darkening color in all experimental groups, as compared to the state prior to starvation, its tunics bulbs continuously. The ratio of RNA/DNA concentrations and protein contents for each of the tunic sections were lower in the starved group. Our results indicate that tunic softness is not related to feeding deficiency, as no histopathological symptoms were apparent in the digestive gland or tunic of H. roretzi due to starvation.

• The Journal of Fisheries Business Administration
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• v.45 no.1
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• pp.33-47
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• 2014

The purpose of this study is to find method to meet the greater retailer's supplier assessment requirement So, this study analyze the greater retailer's requirement for supplier assesment and research global standard which is used instead of supplier assessment requirement that is recognized by global retailers initiative. Next, this study analyze domestic aquaculture certification requirement and compare the global standard with the domestic requirement by using The Most Similar Systems Design. As a result, this comparing has founded all of two domestic certifications are similar to global standard's Good Aquaculture Practice module but those are a little bit different from System Element module. Therefore, this study suggest tree alternative. First, make up for the weak points in the current domestic aquaculture certification system. Second, the introduction of global aquaculture management system certification as supporting by government. Third, development of new standard in accordance with global food standard. This study has major implications for research into development of domestic aquaculture standard.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.4
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• pp.366-371
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• 2011

The sea squirt Halocynthia roretzi is mainly cultured in Tongyeong, Southern coastal area of Korea. This study presents the physiological rates of respiration, excretion, feeding and assimilation efficiency of the sea squirt Halocynthia roretzi to analyze the SFG(scope for growth) and net growth efficiency, determined during 2007. Oxygen consumption and nitrogen excretion rates increased with a rise in temperature during the summer period whereas feeding rates decreased. The O:N ratio was high during winter(October to February). Assimilation efficiency showed an annual average of 75.4% during the experimental period, except during a period of elevated temperature in July to September(average $25^{\circ}C$). Net growth efficiency($K_2$) was 8.7 to 64.2% except for May to September, when temperature increased at the aquaculture farm. SFG was negative from May to September, reflecting high temperatures and low feeding rates during this period; its highest positive values occurred during winter.

• Proceedings of the Korean Aquaculture Society Conference
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• 2004.05a
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• pp.278-279
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• 2004

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.4
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• pp.239-244
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• 2005

The effects of diluents composition on cold storage for olive flounder (Paralichthys olivaceus) sperm were examined in terms of the swimming speed of sperm, the percentage of mobile sperm, and fertilization rates. The following results indicated that cold storage methods with fresh conditions could be employed in olive flounder milt preservation. The preserved sperm of olive flounder that was diluted I: 10 with artificial seminal plasma II (ASP II) and Stein's solution (SS) at $0^{\circ}C$ remained motile for 30 days. The most effective condition for cold storage was ASP II and SS at 0 $0^{\circ}C$ for the sperm, although there is no significant difference statistically. No difference in the fertilization rate was found between fresh sperm and the preserved ones with ASP I, II and SS at 10 days post-storage.

• The Journal of Fisheries Business Administration
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• v.48 no.3
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• pp.47-59
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• 2017

Fish mortality is the most important success factor in aquaculture management. To order fingerlings considering the effect of mortality is a important problem in aquaculture farm. This study is aimed to decision the number and size of fry in aquaculture farm. This study build the mathematical model that finds the value of decision variable to minimize total cost that sums up the fingerling purchasing cost, aquaculture farm operating cost and feeding cost under mortality constraint. The proposed mathematical model involve biological and economical variables: (1) number of fingerlings (2) fish growth rate (3) mortality (4) price of a fry (5) feeding cost, and (6) possible order period. Numerical simulation model presented here in. The objective of numerical simulation is to provide for decision makers to analyse and comprehend the proposed model. When extensive biological and cost data become available, the proposed model can be widely applied to yield more accurate results.

• Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.350-353
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• 2010

This study demonstrated that cryopreserved semen from dead fish can be used for seedling production. Yellow croakers, Larimichthys polyactis, were killed and stored at temperatures of $20^{\circ}C$ or $0^{\circ}C$ for 6 hours. At 2 hour intervals, semen from these fish was collected using abdominal pressure and evaluated for spermatozoa motility and semen cryopreservation. Semen collected after 6 hours from dead fish stored at $0^{\circ}C$ could be cryopreserved and attained fertilization and hatching rates of $15.0{\pm}1.2%$ and $14.8{\pm}1.6%$, respectively. This study suggests that germ cells such as the semen of dead fish can be cryopreserved and utilized in the restoration of a species.