• Title/Summary/Keyword: Tresus Keenae

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Reproductive Cycle of Surf Clam (Tresus keenae) in Southern Coast of Korea (남해안에 서식하는 왕우럭 (Tresus keenae)의 생식주기)

  • KIM Dae Hee;LIM Han Kyu;MIM Kwang Sik;CHANG Young Jin;KIM Tae Ik
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.32 no.5
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    • pp.659-663
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    • 1999
  • Gametogenesis, reproductive cycle, condition factor, and meat weight rate of the surf clam, Tresus Keenae were studied by histological observations and morphometric data based on the samples which have been collected from the south coast of Korea, from January 1995 to February 1996. The annual ranges of the mean seawater temperature and specific gravity in habitat of the surf clam were $4.9\~24.9^{\circ}C$ and 1.0210$\~$1.0266, respectively. Monthly changes in the condition factor showed in a wide range from 0.2381 to 0.2827, began to increase in January and reached the first maximum (0.2827) in April. And then the value rapidly decreased in June, thereafter, reached the second peak (0.2812) in August. The condition factor of this species showed the two peaks, and gonadal development reached sexually mature and ripe conditions during the period of these two peaks. The meat weight rate ranged from $38.0\%$ to $46.4\%$, and its change showed a similar tendency with the condition factor. The reproductive cycle of this species can be divided into five successive stages: in both sex, multiplicative (December to January, July to August), growing (January to February, September to October), mature (February to April, September to November), spawning (April to June, September to November), and degenerative and resting stage (May to July, November to January).

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Nutrient Components in the Siphon of the Surf Clam Tresus keenae

  • Choi, Jong-Hwa;Shin, Tai-Sun;Ahn, Chang-Bum
    • Fisheries and Aquatic Sciences
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    • v.8 no.2
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    • pp.43-50
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    • 2005
  • We evaluated the nutritional composition of the siphon of the surf clam Tresus keenae in regard to the presence of nitrogenous [amino acids, nucleotides and their related compounds, total creatinine, betaine, trimethylamine oxide (TMAO), and trimethylamine (TMA)] and non­nitrogenous compounds (sugars and organic acids), lipid fatty-acid composition, and occurrence of minerals. The content of total free amino acids was 660.27 $\pm$ 7.94 mg/100 g, and the predominant amino acids were arginine, alanine, sarcosine, glycine, and glutamic acid. These amino acids accounted for $71\;\%$ of the total free amino acids. Among the nucleotides and their related compounds, inosine was the major component and comprised 40.38 $\pm$ 0.02 mg/100 g. Free amino acids were the largest contributor to total extracted nitrogen, comprising $49.94\%$, followed by total creatinine, betaine, nucleotides, and ammonia; the contribution of TMAO and TMA was small. For the non-nitrogenous compounds, malic acid, propionic acid, and succinic acid comprised the major portion of the ten kinds of organic acids detected, and the sugars found were glucose, maltose, and arabinose, which were estimated to be $147.0\pm7.15,\;34.45\pm1.09,\;and\;1.21\pm0.02\;mg/100\;g,$ respectively. The predominant minerals were Na and K, which comprised $11.43\pm1.06\;and\;9.46\pm1.02\;mg/100\;g,$ respectively. The major fatty acids were C22:6, C20:5, C23:0, C18:3, and C16:0 in the lipid fractions. The 23:0 level of glycolipid (GL) was the highest of any other lipid fraction. The amount of total polyunsaturated fatty acids (PUFA) in the lipid fractions was higher, ranging from $58.22\%\;in\;GL\;to\;77.1\%$ in phospholipid (PL), compared to the saturated and monounsaturated fatty acids. Of the n-3 fatty acids, C20:5 and C22:6 contributed $35.30-64.44\%$ of PUFA in the lipid fractions. The ratios of n-3 to n-6 PUFA in total lipid (TL), neutral lipid (NL), PL, and GL were 4.35, 4.26, 6.69, and 2.04, respectively.

Clearance and ingestion rate according to different culture condition in the sulf clam, Tresus keenae (사육조건에 따른 왕우럭, Tresus keenae의 여수율과 먹이섭취률)

  • Kim, C.W.;Jeong, D.S.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.14 no.1
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    • pp.107-115
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    • 2012
  • In juvenile size, the maximum clearance rate and ingestion rate were 15mm, which is the 70.8 mL/h, 4245.0×104cells/h, respectively. But the lowest clearance rate and ingestion rate were found at 5mm, which is the 4.1 mL/h, 246.0×104cells/h, respectively. The highest clearance rate and ingestion rate of AFDW seen at 7.5mm, with 3.3 mL/mg AFDW/h, 196.0×104cells/mg AFDW/h, respectively. According to the results of water temperature, clearance rate and ingestion rate were lowest at 10℃, showing the 0.3 mL/h, 20.3×104cells/h, respectively. The highest clearance rate and ingestion rate were 25℃, which is the 16.6 mL/h, 993.4×104cells/h, respectively. But in 30℃, clearance rate and ingestion rate decreased to the 12.9 mL/h, 772.6×104cells/h, respectively. With respect to the food density, the experiment groups with 30×104 cells/mL and 240×104 cells/mL showed the clearance rate of 21.1 mL/h and 2.3 mL/h, respectively. But the experimental group with 120×104 cells/mL or more showed decreased clearance rate. While, the maximum ingestion rate was at 60×104 cells/m, showing the 876.2×104cells/h.