• 한국어류학회지
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• 제12권1호
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• pp.62-70
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• 2000

1997년 7월부터 1999년 6월까지 2년간 제주도 남부 해역인 하예동 연안에서 매월 채집한 쥐치, Stephanolepis cirrhifer의 생식주기를 조직학적 방법으로 연구하였다. 암 수컷의 월별 GSI 변화는 월별 수온과 광주기 변화양상과 거의 유사하게 변화하였고 암 수컷 모두 GSI값이 6월에 년 중 최고값을 보였다. 생식주기는 암컷인 경우 성장기 2~5월, 성숙기 5~6월, 산란기 6~8월, 퇴화 및 휴지기 9~12월로 구분되고, 수컷인 경우 성장기 2~4월, 성숙기 5~6월, 방정기 6~8월, 퇴화 및 휴지기 9~1월로 구분할 수 있었다. 성숙시기에 쥐치의 난소를 조직학적으로 관찰한 결과 난소내에는 여러 발달 단계의 난모세포들이 분포하여 비동시발달형에 속하는 어종으로 판단되며 산란기동안 적어도 2회 이상 산란하는 다회산란어에 속하는 어종으로 사려된다.

• 한국수산과학회지
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• 제40권3호
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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.

• 한국발생생물학회지:발생과생식
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• 제25권3호
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• pp.145-155
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• 2021

Reproductive cycle of the blue-striped angelfish, Chaetodontoplus septentrionalis were histologically investigated. Fish were monthly collected in the coastal waters of Munseom, Seogwipo, Jeju-Island from February to December 2018. The gonadosomatic index (GSI) increased from May and maintained high values in August. The reproductive cycle of female fish can be classified by the characteristics observed during gonadal development as followed: growing stage (November to June), early mature stage (May to June), mature and spawning stage (June to September), and degenerative and recovery stage (September to December). In the male, testicular development period was similar to that of ovarian development period, but mature and spawning period was one month longer from June to October. Fecundity of mature female ranged from 4,601 to 22,840 and was correlated positively with total length and body weight. The histological analysis of gonadal development indicated that the C. septentrionalis was summer-spawning type and is considered a multiple spawner during spawning season.

• 한국어류학회지
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• 제12권1호
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• pp.71-84
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• 2000

1997년 7월부터 1999년 6월까지 2년간 제주도 남부해역인 중문 하예동 연안에서 매월 채집한 말쥐치, Thamnaconus modestus의 생식주기를 조직학적인 방법으로 연구하였다. 암 수컷의 GSI 변화에 있어서 암컷은 5월, 수컷은 6월에 년 중 최고값을 보였다. 생식주기는 암컷인 경우 성장기 3~4월, 성숙기 4~5월, 산란기 5~6월, 퇴화 및 휴지기 7~2월로 구분되었고, 수컷인 경우 성장기 1~3월, 성숙기 4~5월, 방정기 5~6월, 퇴화 벚 휴지기 7~12월로 구분할 수 있었다. 산란기간 동안 말쥐치 암컷을 대상으로 이들의 산란주기 및 산란횟수를 알아보기 위해 생식소 발달상을 조직학적인 방법으로 관찰하고 성 steroid 호르몬인 estradiol-$17{\beta}$ ($E_2$)와 testosterone (T)의 혈중 농도를 RIA 검사를 통하여 조사한 결과 말쥐치는 비동시발달형에 속하는 어종으로 산란기간내 적어도 2 회 이상 산란을 하는 다회산란종으로 추정되며, $E_2$와 T의 혈중 농도 변화는 난모세포의 성숙과 GSI 변동에 거의 상동적으로 변화하고 있었다.

• 한국수산과학회지
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• 제48권5호
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• pp.739-744
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• 2015

The sexual maturation and spawning time of female ocean sunfish Mola mola in Korean waters were studied by observing the gonads histologically. Specimens were purchased in a fish market in October 2013 and May, June, and October 2014. Nine females (total length 100-250 cm, gonad weight 31-3,470 g) and one male (total length 131 cm, gonad weight 60 g) were studied. Histologically, the ovaries became active in May and spawning began in July and continued until October. In July, mature oocytes and yolk globule stage oocytes were observed; parts of the gonad showed traces of spawning, while others had degenerated and absorbed any oocytes. By October, many oocytes had degenerated and been absorbed. Therefore, the approximate spawning period of ocean sunfish is from July to October based on histological changes in the gonads. The asynchronous oocyte development suggests that the ocean sunfish is a multiple spawner, as reported previously. The catch distribution data suggest that the waters around Jeju Island are a sunfish spawning area.

• Animal cells and systems
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• 제8권1호
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• pp.33-40
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• 2004

Reproductive cycle and spawning rhythm with lunar cycle of the ascidian, Halocynthia hilgendorfi ritteri were investigated by histological examination. The specimens were sampled in the coastal waters of Yongdam, northwest of Jeju Island, Korea, from November 2001 to January 2003. H. hilgendorfi ritteri is a synchronous hermaphrodite; the gonads are located in the mantle. The reproductive cycle can be grouped into the following successive stages in the ovary: growth (February to June), vitellogenesis (April to September), mature (July to December), spent (November to February), and recovery (December to April). Likewise, in the testis, the stages observed were: growth (October), mature (October to December), spent (November to February), and resting (January to September). Major spawning probably occurs between November and January, when water temperatures decrease. The histological observations of the gonads suggested that this species is a multiple spawner during the spawning period. Spawning occurred between the new moon and full moon, and again between the full moon and new moon, suggesting that the spawning rhythm is influenced by the lunar cycle.

• 수산해양기술연구
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• 제48권2호
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• pp.118-127
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• 2012

The reproductive ecology of the glowbelly, $Acropoma$ $japonicum$ was examined using 637 specimens collected monthly from January to December 2006 in the coastal waters off Gori, Korea. The specimens ranged in standard length (cm, SL) from 2.9 to 11.4cm for female, 2.7 to 10.5cm for male. The gonadosomatic index (GSI) of female was highest in September and decreased until December, and the spawning season lasted from August to November. The monthly sex was not different significantly ($x^2$-test, p>0.05). The size at 50% maturity was estimated at 6.0cm SL. $A.$ $japonicum$ was multiple spawner that spawn on more than one occasion in a single spawning season, and the maximum egg diameter was 0.75mm. Fecundity (F) ranged from 12,052 to 104,246 eggs, with the mean of 38,321 eggs. The relationships between fecundity and standard length (cm, SL), body weight (g, BW) were estimated as $F=86.278SL^{2.9652}$ ($R^2$=0.7970) and $F=3036BW^{1.0081}$ ($R^2$=0.7992), respectively.

• 한국발생생물학회지:발생과생식
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• 제25권3호
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• pp.157-171
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• 2021

To determine whether the reproductive processes of sea bass, Lateolabrax japonicus, proceed normally after transportation from an outdoor net-cage into indoor tanks, we examined changes in the gonadosomatic index (GSI), histological gonadal tissue, and plasma levels of sex hormones (testosterone and estradiol-17ß) during their annual reproductive cycle. We also measured maturation and spawning across two sea water salinity levels (full and low salinity). Fecundity was estimated by the relationship between egg number and body size in female sea bass. Monthly changes in the GSI, histological gonadal tissues, and oocyte size showed both male and female sea bass reach final maturation in January and February, respectively, indicating that the spermiation of males occurs earlier than the spawning of females. The histological results indicated that the sea bass is a multiple spawner, similar to many marine teleosts, exhibiting group-synchronous oocyte development. Female maturation and spawning were enhanced in lower salinity seawater (29.6-31.0 psu) compared to that of normal salinity (34.5-35.1 psu). These results confirm that sea bass reproduction can occur successfully in captivity and imply that fertilized eggs can be collected from February to March. Additionally, our results show that lower salinity enhances oocyte maturation and spawning of female sea bass.

• 한국양식학회지
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• 제9권1호
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• pp.73-81
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• 1996

농어목 어류인 Caesio diagramma의 생식주기를 밝히기 위하여 난모세포의 발달과정을 조직학적 방법으로 관찰하였다. 난모세포의 발달과정은 염색인기, 주변인기, 유구기, 제1차 난황구기, 제2차 난황구기 및 제3차 난황구기의 6단계로 구분되었다. 염색인기와 주변인기의 난모세포는 연중 관찰되었으며, 난모세포 발달과정에서의 특징은 난소 내에서 유구가 초기에 형성되며, PAS 염색 결과 난황포는 타어류에 비하여 크기가 작았고 양도 적었다. 4월에 채집된 어류의 난소에서는 난황 형성기의 난모세포가 출현하기 시작하였다. $5\~6$월의 난소에서는 제3차 난황구기 난모세포가 관찰되었으며, 연중 가장 높은 비율을 나타냈다. 또한, 이 시기부터 난소의 일부에서는 배란을 마친 여포와 퇴화중인 난모세포도 다수 관찰되었으며, 7월까지 이어졌다. 9월 이후의 난소에서는 난황 형성기의 난모세포가 관찰되지 않았으며, 12월까지 염색인기 및 주변인기의 난모세포가 주류를 이루었다. 생식소중량지수(GSI)와 간중량지수(HSI)는 4월부터 증가하기 시작하여, $5\~6$월에 최고치에 도달하였으며 GSI와 HSI의 변화는 난모세포의 발달과정과 일치하였다. 따라서 C. diagramma의 주산란기는 $5\~6$월이며, 난소의 발달과정과 여러 형태의 여포가 존재하는 점으로 미루어, 본 종은 비동기발달형의 난소를 가지며 다회산란 어류에 속한다.

• 한국발생생물학회지:발생과생식
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• 제17권4호
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• pp.421-426
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• 2013

In this study, oocyte steroidogenesis are investigated in relation to oocyte development in the starry flounder, Platichthys stellatus, a marine multiple spawner. Vitellogenic (0.52 and 0.55 mm oocyte diameter) and mature oocytes (0.63, 0.66 and 0.71 mm oocyte diameter) were incubated in vitro in the presence of $[^3H]17{\alpha}$-hydroxyprogesterone ($[^3H]17{\alpha}$-OHP) as a precursor. Steroid metabolites were extracted from the incubated media and oocytes, the extracts were separated and identified by thin-layer chromatography (TLC), high performance liquid chromatography (HPLC) and gas chromatographymass spectrometry (GC-MS). The major metabolites produced from $[^3H]17{\alpha}$-OHP were androgens [androstenedione ($A_4$) and testosterone (T)] and estrogens [$17{\beta}$-estradiol ($E_2$) and estrone ($E_1$)] and progestins [$17{\alpha},20{\alpha}$-dihydroxy-4-pregnen-3-one ($17{\alpha}20{\alpha}P$) and $17{\alpha},20{\beta}$-dihydroxy-4-pregnen-3-one ($17{\alpha}20{\beta}P$)] in vitellogenic and mature oocytes. The results from this study suggest the potential roles of $E_1$ in the oocytes with diameter 0.52-0.71 mm, $17{\alpha}20{\alpha}P$ and $17{\alpha}20{\beta}P$ at the oocytes of 0.63, 0.66 and 0.71 mm.