• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.712-718
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• 2015

The effects of salinity on survival, oxygen consumption, and hematological response of greenling Hexagrammos otakii, mean body weight 147.1±3.8 g, were investigated under salinity conditions of 33.4 (control), 33.1, 32.8, 32.2, 31.0, 28.7, 23.9, 14.5, and 3.8 psu, to evaluate physiological effects in relation to changes in salinity. The survival and hematological responses of fish were measured at each salinity after 96- and 24-h exposures. The oxygen consumption rate (OCR) of fish was measured in triplicate under conditions of stepwise salinity exposure (33.4→33.1→32.8→32.2→31.0→28.7→23.9→14.5→3.8 psu) with an interval of 24 h at each salinity, using a continuous flow-through respirometer. No fish mortality was observed in the range of 33.4 to 14.5 psu, but the survival rate was reduced to 53.3% at 3.8 psu after 96 h of exposure. The OCRs did not significantly differ in the range between 33.4 to 28.7 psu (P>0.05), but significantly increased at 23.9 and 14.5 psu, and then dramatically decreased at 3.8 psu compared to the control (P<0.05). Hematological variables, such as glucose, glutamic pyruvic transaminase (GPT), hematocrit, and Na⁺, were affected by reduced salinity. This result may be applicable for habitat and culture management of greenlings.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.3
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• pp.153-159
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• 2007

We studied oocyte steroidogenesis in relation to oocyte development in the greenling, Hexagrammos otakii, a marine multiple spawner. Vitellogenic and mature oocytes were incubated in vitro in the presence or absence of $[^3H]-17\;{\alpha}-hydroxyprogesterone$ as a precursor. The major metabolites were androgens [androstenedione $(A)_4)$ and testosterone (T)] and estrogens [$17\;{\beta}-estradiol\;(E_2)$ and estrone ($E_1$)] in vitellogenic oocytes. The metabolic rate of T was lower in 1.08 to 12-mm oocytes, while that of $E_2$ increased with oocyte size. The endogenous productions of T, $E_2$ and 17 ${\alpha}-hydroxy$, 20 ${\beta}-dihydroprogesterone\;(17{\alpha}20{\beta}OHP)$ were quantified using a radioimmunoassay in the non-precursor group. The endogenous levels of T and $E_2$ were highest in 1.08 to 12-mm oocytes and $17{\alpha}20{\beta}OHP$ was produced only in 1.90 to 95-mm oocytes. The relationship between oocyte size and steroidogenesis showed that 1.08 to 12-mm oocytes are full vitellogenic following induction of the maturation process. Moreover, $17{\alpha}20{\beta}OHP$ acts as a maturation inducing hormone in H. otakii.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.3
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• pp.287-295
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• 2013

The growth, respiration, ingestion, and ecological efficiencies of Hexagrammos otakii larvae and juveniles reared on different diets and temperatures were estimated. A factorial experiment using two diets [non-enriched hatched Artemia nauplii (NEA) and enriched Artemia nauplii (EA)] crossed with two temperatures [natural seawater temperature (NT, $5.1-8.5^{\circ}C$) and heated seawater (HT, $13{\pm}0.5^{\circ}C$)] was conducted to investigate growth and energy budgets of Hexagrammos otakii larvae and juveniles. The energy used by larvae and juveniles for 6 weeks was calculated using data on ingestion, growth, respiration, excretion, and egestion. In the NT trials, the energy used for growth by larvae and juveniles was 0.121 and 0.129 Kcal in the NEA and EA treatments, respectively. Assimilation efficiency at NT were 78.0% and 80.2% in the NEA and EA trials, respectively. Gross growth efficiency ($K_1$) were 60.5% and 62.3% and net growth efficiency ($K_2$) was 77.56% and 77.71% in the NEA and EA trials, respectively. In the HT trials, the energy used for growth by juveniles was 0.189 and 0.212 Kcal in the NEA and EA trials, respectively. Assimilation efficiency at HT was 86.4% and 95.1% in the NEA and EA trials, respectively. Values of $K_1$ and $K_2$ at HT were 69.5% and 80.43%, respectively, in the NEA trials, and 73.9% and 77.66%, respectively, in the EA trials. These results suggest that enriched Artemia nauplii and higher temperatures ($13{\pm}0.5^{\circ}C$) are effective for rearing larvae and juveniles of H. otakii.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.2
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• pp.75-81
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• 1983

The studies on the age determination of the spottybelly greenling, Agrammus agrammus, caught in the shore of Tongbaeksom were done by the articulative fossae of the vertebra through a stero-dissecting microscope. For determining annunli the vertebra had been cleaved lengthwise in the dorsoventral direction. Half of the vertebra had been fixed on Canada balsam with the flat side directed upwards. The alternation of two zones on the vertebra was observed. One is wide and light-colored, and the other is narrow and dark-colored. The annual layer, where the dark-colored zone shifts to the light-colored one, was appeared extending from July to August once a year. Study of the growth of A. agrammus was carried out by the method of back calculation from the vertebra.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.676-681
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• 2002

Different types of transcripts encoding growth hormone (GH) were identified from cDNA libraries constructed with pituitaries of a marine fish species, greenling (Hexagrammos otakii). GH-homologous cDNA clones were isolated using the high-density filter hybridization and the expressed sequence tag techniques. Of 39 full-length positive cDNA clones, 31 clones ($79\%$) displayed an identical sequence, however, remaining 8 clones exhibited several polymorphisms in their sequences including (1) the length and sequence variability in the 5' upstream region, (2) insertional sequences in open reading frame, and (3) deletion and/or single nucleotide polymorphism in the untranslated 3' region. Based on RT-PCT and RNA dot blot analyses, these transcripts were proven to be expressed in a pituitary-specific manner.

• Journal of fish pathology
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• v.14 no.1
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• pp.54-58
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• 2001

The seasonal trends of plasma protein and glucose concentrations in marbled soles(Limanda yokohamae) and greenlings(Hexagrammos otakii), and the influence of transport stressor on those levels were investigated. Total plasma protein levels of marbled soles and greenlings in late spring and summer were significantly higher than those in winter(January). Plasma glucose levels were consistently increased according to elevation of water temperature both in marbled soles and greenlings. Transport stressor gave rise to decrease of plasma protein levels and increase of blood glucose levels.

• Fisheries and Aquatic Sciences
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• v.18 no.4
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• pp.395-399
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• 2015

We observed seasonality and other characteristics of spawning in the greenling Hexagrammos agrammus off the coast of Tongyeong. Eleven spawning grounds were identified between November, 2013 and January, 2014. The fertilized eggs of H. agrammus were assigned to developmental stages I, II, III, and IV. Based on this classification, we showed that the spawning season extended from the end of October to mid-January. H. agrammus used diverse seaweed species attached to shallow bedrock as spawning substrata that provided good camouflage. Two to seven egg masses were fertilized around the holdfasts of individual seaweeds at depths of 1.2-4.0 m. We identified species-specific reproductive traits of H. agrammus during the spawning season, including strong parental care of the fertilized eggs.

• Korean Journal of Ichthyology
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• v.5 no.2
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• pp.151-159
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• 1993

Greeling, Hexagrammos otakii Jordan et Starks is commonly found at the coastal waters of Korea and Japan. The authors carried out the artificial insemination in the laboratory on Dec, 17, 1987, and reared the hatched larvae in an aquarium. The eggs were demersal and adhesive, and their diameters were 2.00~2.15mm. Color of yolk was light yellow in the early stage, and then turned to orange before hatching. The yolk had numerous tiny oil globules. Hatching began about 477hours after insemination under water temperature of $10.0{\sim}14.5^{\circ}C$. The newly hatched larvae were elongate in shape and 7.48~8.25mm in total length(TL) with 49~50 myomeres. The larvae absorbed the yolk material and oil globules completely in 5days after hatching and became postlarvae. In 17days after hatching, mean total length of the larvae was 9.85mm, and the caudal notochord flex at $45^{\circ}$. In 23days, total length reached 10.54mm. The part of the fin-fold of the future dorsal and anal fins became high. Spawning season of the Greenling is known to be from November to January in the southern coast of Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.1
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• pp.83-91
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• 1986

The activity of the liver cells of greenling, Agrammus agrammus were histologically investigated under photo-and electron microscopy, and studied by comparing seasonal changes of hepatosomatic index (HSI). The materials were monthly collected at the costal area of Tongbaeksom, Pusan, Korea, from September 1983 to August 1984. The annual variations of HSI of male were not distinct, but those of HSI in female began to increase in autumn, and reached the maximum in winter when the ovary was getting mature. During the period of yolk accumulation in the oocytes, the female liver and its hepatic cells were seen to large and nuclei and nucleoli were hypertrophic also. At this time the amounts of glycogen and lipid in the cells gradually decreased, while basophilic substance (RNA) increased. And well-developed granular endoplasmic reticula binding ribosomes were supposed to play the leading role in protein synthesis and deposition for vitellogenin in the cystoplasm. Just prior to spawning, glycogen and lipid droplets were decreased, but basophilic substances(RNA) were found in a high concentration especially at the peripheral region of the liver cells of females. In the liver cells of males, were hardly altered by gonadal maturation, basophilic substances gradually increased, glycogen particles and lipid droplets were still observed in large quantities. After spawning, basophilic subtances decreased in the liver cells of female and male.

• Journal of Life Science
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• v.21 no.11
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• pp.1565-1572
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• 2011

Eye-specific lactate dehydrogenase (EC 1.1.1.27, LDH) $C_4$ isozyme in the eyes of greenlings (Hexagrammos otakii) was successfully purified by affinity chromatography and continuous-elution electrophoresis. The molecular weight of the purified eye-specific LDH $C_4$ isozyme was 154.8 kDa, as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Optimal pH for enzymatic reaction of the eye-specific LDH $C_4$ isozyme was pH 8.5. $K^{PYR}_m$ value of the purified eye-specific LDH $C_4$ isozyme was $1.88{\times}10^{-5}$ M using pyruvate as a substrate. These results indicate that we must consider pH when measuring eye-specific LDH $C_4$ isozyme activity. The eye-specific LDH $C_4$ isozyme had a higher binding affinity for the substrate as a pyruvate than LDH A4 isozyme. Antibodies produced against the purified eye-specific LDH $C_4$ isozyme may be used in the diagnosis of several human diseases and in comparative physiological studies of fishes.