• Korean Journal of Environment and Ecology
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• v.27 no.4
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• pp.429-436
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• 2013

Churyeong Stream flows 37km from the mouth of Lake Okjeong and is impeded by many weirs that hamper the active movement of land-locked sweet smelt fish (Plecoglossus altivelis) that ascend and descend between the lake and the upper stream. In late December 2006, a fishway was constructed in a weir of the lower reach of Churyeong Stream, where juveniles begin their ascent to mature upstream. At 13 sites along the stream from April to October 2007, we investigated the effects of the newly constructed fishway on sweet smelt growth. After construction of the fishway, juvenile sweet smelt were able to migrate freely upstream, something that had previously only been possible when the weir was in flood. The body size of mature sweet smelt collected during the spawning season in September 2007 was greatly increased compared to previous seasons, measuring an average of $163{\pm}21.5mm$ in standard length. These measurements were 13mm, 20mm, and 57mm longer than body length averages for mature sweet smelt collected in 2006, 2004, and 2005, respectively. Therefore, it is likely to be necessary for the construction of fishways on streams and rivers containing land-locked sweet smelt populations to increase average body sizes and viability.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.99-100
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• 2001

Although cultured sweet smelt production recently have been rapidly increased from 89 metric tons (M/T) in 1997 to 500M/T In 1999 in Korea, wild fish have been still used as broodstock for cultured fish seed. This is considered due to having higher sperm and e99 qualify in wild fish broodstock than cultured fish. However, capturing a number of wild sweet smelt broodstock might lead to decreasing of the production of wild fish, In truth, of which production has been greatly decreased so that a number of artificial juvenile have been stocked some rivers in Korea. (omitted)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.97-98
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• 2001

Alpha-tocopherol (alpha-Toc) is a classical lipophilic antioxidant well known as a scavenger of free radicals in a hydrophobic milieu. The primary function of alpha-Toc is to stabilize cellular and subcellar membrane by preventing peroxidative damage of structural polyunsaturated fatty acids (PUFA). The characteristic aroma of sweet smelt Precoglossun altivelis is known as oxida breakdown products of PUFA ironically. (omitted)

• Fisheries and Aquatic Sciences
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• v.4 no.4
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• pp.163-170
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• 2001

The effect of perilla oil added in diet on the biochemical properties of cultured sweet smelt, Plecoglossus altivelis, was investigated. The cultured fish were fed two different diets for 8 weeks; a control diet was a commercial diet, which was low in the content of docosa­hexaenoic acid (DHA, 22: 6n-3) and eicosapentaenoic acid (EPA, 20: 5n-3) less than approximately $2\%$ (CO group) and an experimental diet (PO group) was added perilla oil as a lipid source in the diet of the CO group. The PO group was superior in growth rate and feed efficiency compared with CO group. This trend showed markedly in female of both groups. The fatty acid composition in the muscle of PO group was closely related with those of the diet, while those of CO group were not. For plasma components, total cholesterol (CHOU of PO group was higher than that of CO group. Thiobarbituric acid-reactive substances (TBARS), hydroxyl (OH) radical levels and superoxide dismutase (SOD) activity of plasma were higher in PO group than CO group. The intensity of watermelon-like or cucumber-like aroma was much stronger in PO group with higher level of TBARS and OH radical in plasma compared CO group. Survival rate was also high in PO group with high levels of phagocytic rate, CHOL and SOD activity. These results suggest that perilla oil might be usefulness as a lipid source of the cultured sweet smelt diet, in which result in high quality of the cultured fish.

• Applied Microscopy
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• v.41 no.1
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• pp.13-20
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• 2011

The ultrastructure of the matured egg envelope in Pond smelt, Hypomesus nipponensis belonging to Osmeridae, Osmeriformes were investigated by routine light and electron microscopes. The matured egg have two egg envelopes and have a single micropyle, which is thought to the pathway of sperm in the area of the animal pole. An outer egg envelope was surrounded by a follicular layer and outer surface of inner egg envelope have structure with high electron density. Also, the inner egg envelope consisted of 6 horizontal lamellae with higher electron density alternating with 5 interlamellae of lower electron density. Many grooves distributed on the outer surface of outer egg envelope, and the outer surface of inner egg envelope was covered by amorphous structures. In conclusion, the egg of teleost is surrounded by one egg envelope according to the studies on morphology of egg envelope up to the present. The fact that have two egg envelopes is a species specificity of Pond smelt and these ultrastructural characters of egg envelope can be utilized in taxonomy of teleost.

• Korean Journal of Environmental Biology
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• v.23 no.1
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• pp.89-92
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• 2005

The effect of cement on survival, LC/sub 50/, safe concentration (SC) and application factors of pollutant (AF) for pond smelt, Hypomesus olidus were investigated for 96 hours. Mean body length of pond smelt used in this experiment was 8.6±1.2 cm. Cement concentrations established in this experiment were 0 (control group), 10, 25, 50, 100, 250, 500, and 1,000 ppm, respectively. All fishes were dead in concentration more than 500 ppm cement within 4 hours. The LC/sub 50/ to cement toxicity was 123.03 ppm for 48h, 91.20 ppm for 72 h and 58.88 ppm for 96h. The value of SC and AF to cement toxicity for this species were 2.64∼9.14 ppm and 0.045∼0.155, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.6
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• pp.689-692
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• 1999

Proximate compositions of muscles and eggs between wild sweet smelt which were caught in Seomjin river and Miryang river, and cultured sweet smelt which were purchased from certain cultured farms in Hadong and Miryang, were compared. Proximate compositions of wild sweet smelt muscles were $76.7\~77.5\%$ for moisture, $18.4\~19.9\%$ for protein, $2.41\~3.47\%$ for lipid, and $1.04\~1.33\%$ for ash content and there were almost no differences between the fishes from Seomjin and Miryang river. Protein and ash content in the cultured fish muscles were similar to those of the wild fish muscles, while the former contained much more lipid and carbohydrate, and less moisture than the latter, especially lipid content differed greatly according to their cultured farms. This might be the result of their different diet compositions. Lipid, protein and carbohydrate content in eggs of the wild and cultured fishes were much higher than those in their muscles. There was a negative correlation between moisture and lipid content in all samples; y= -0.2715x+24.903 (r= -0.7253, p<0.001).

• Fisheries and Aquatic Sciences
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• v.7 no.1
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• pp.1-9
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• 2004

Sweet smelt (Plecoglossus altivelis) were fed four different diets supplemented with either perilla oil $(2.0\%)$ rich in 18:3n-3 (CP), and perilla oil and Enteromorpha compressa meal $(2.0\%)$ (CPA), soybean oil rich in 18:2n-6 (CO), or soybean oil and algal meal (CA) for 4 weeks. The growth performance, fatty acid composition of muscle, plasma lipid peroxidation and blood components of the sweet smelt were then determined. The specific growth rate and feed efficiency in the fish fed the CPA diet were the highest, while the other groups showed similar results. The fatty acid composition of muscle in sweet smelt reflected the dietary lipids; 18:3n-3 was higher in the fish fed the CP and CPA diets, and 18:2n-6 was higher in the fish fed the CO and CA diets. The other fatty acid profiles presented almost no differences with respect to the diet composition. The fish fed the CA, CP and CPA diets contained significantly lower levels of triglyceride, thiobarbituric acid-reactive substances and hydroxyl radical in their plasma than that fed the CO diet. Phagocytic activity was the highest in the fish fed the CPA diet and higher in those of the fish fed the CP and CA diets compared to the CO diet group. The results from this study suggest that a dietary supplement of $2.0\%$ perilla oil together with $2.0\%$ E. compressa meal may improve the growth and health of cultured sweet smelt.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.4
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• pp.419-421
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• 2001

Heritability estimations of masu salmon smelt at underyearing of age were described. Masu salmon was taken from aquaculture station of Mori in Japan. After fertilization, the offsprings in each family were reared in separate egg trays and fingerling tanks. The percentage of fish in each tank which smoltified at 11-month old was recorded, and environmental and genetic factors influencing the percentage smoltification were also studied. Percentage of smoltification was not significantly affected by the number of fish held in a tank, or fish density (correlation coefficient 0.10). However, there was a high correlation ($0.821\~0.565$) between smelt percentage and growth related traits of fish in a family. Heritability estimated from total data was $0.47\pm0.13$, when effects of tanks were ignored.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.2
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• pp.264-271
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• 2011

The effect of replacement of fish meal (FM) in diets with sand smelt meal (SSM) on fatty acid composition of carp fry, Cyprinus carpio, was examined. Five isonitrogenous and isoenergetic (38% crude protein, $15.75\;kJ\;g^{-1}$) diets replacing 0, 25, 50, 75, and 100% FM protein by SSM protein were formulated. Each diet was randomly allocated to triplicate groups of fish in aquaria, and each aquarium was stocked with 20 fish (initial average weight of $0.300{\pm}0.65\;g\;fish^{-1}$). Fish were fed twice daily to apparent satiation for 13 weeks. Results indicated that final weight, specific growth rate and feed efficiency ratio of fish fed with different SSM replacement diets did not differ significantly (p>0.05) from fish fed the control diet, except for 100% SSM level. No significant differences were noted among experimental treatments on dry matter, protein, lipid and ash contents of the fish body composition (p>0.05). Fatty acid analysis showed that saturated fatty acids in fish muscle significantly decreased, but monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) did not change with increasing dietary SSM. However, some changes also could be observed for some particular fatty acids in experimental fish. For example, the amounts of 15:0, 17:0, 18:1n-7, 18:2n-6 and 22:5n-3 significantly increased, but 16:0, 18:1n-9, 18:3n-3 and 20:1 n-9 significantly decreased with increasing dietary SSM. Total n-6 PUFA increased with increasing dietary SSM, but total n-3 PUFA were not changed in muscle of fish fed the experimental diets. The ratio of n-3 to n-6 was not affected significantly in muscle of fish fed the experimental diets containing different proportions of SSM, including the control diet.