• 한국어류학회지
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• 제20권1호
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• pp.13-20
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• 2008

줄납자루를 이용한 외부생식형질의 정량화 가능성을 통하여 이를 어류의 생식관련 연구에 적용할 수 있는지 여부를 확인하기 위해 내부생식형질과 비교하였다. 줄납자루의내부생식형질은 GSI, HSI 및 생식소 발달단계를 이용하였으며, 외부생식형질은 암컷의 경우 산란관의 발현 및 산란관지수의 변화, 수컷의 경우 추성의 발현 및 수의 변화 그리고 꼬리지느러미와 등지느러미에 나타나는 혼인색의 발현 및 혼인색지수의 변화를 이용하였다. GSI와 HSI는 암컷과 수컷 모두 2월에 가장 높은 값을 나타냈으며, 생식소 발달단계는 암컷과 수컷 모두 2월에서 5월 사이에 완숙 및 방란 방정기의 조직상을 가진 개체들이 대부분을 차지하고 있었다. 산란관은 12월~5월 사이에 전 개체에서 신장되었으며, 산란관지수는 3월~4월 사이에 가장 높은 값을 나타냈다. 추성, 등지느러미 및 꼬리지느러미의 혼인색 발현율 및 각 지수들은 2월~5월(꼬리지느러미의 경우 2월~4월) 사이에 가장 높은 발현율과 값을 나타냈다. 이와 같은 결과들은 암컷과 수컷 모두 내부 및 외부생식형질이 동일한 변화를 보여주고 있는 것으로써, 추후 생식관련 연구를 수행하는 데 있어 보다 나은 자료를 제공할 것으로 생각된다.

• 한국어류학회지
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• 제29권3호
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• pp.176-189
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• 2017

경기도 가평군의 가평천 일대에서 2016년 9월과 2017년 2, 4월에 쉬리 245개체를 채집하여 이석과 전장빈도분포법을 이용한 연령추정과 23가지의 계측형질을 이용하여 연령에 따른 성적이형을 조사하였다. 연령추정 결과 만 2년생부터 만 4년생의 비율이 높았고 만 5년생이 최대연령이었다. 23개의 계측형질 중 9개의 형질에서 성별 간에 유의한 차이가 있었다. 이중 뒷지느러미에서 나타나는 성적이형은 수컷의 뒷지느러미 연조가 길게 신장되어 뒷지느러미 폭과 길이가 암컷에 비해 넓고 긴 특징을 보이는 주요한 성적이형으로 나타났다. 또한 산란기에 수컷개체는 뒷지느러미의 연조에 추성이 발달하는 성적이형을 나타내었으나 뒷지느러미를 제외한 다른 계측형질과 외부형질에서 성별에 따른 성적이형이 나타나지 않았다. 성적으로 성숙하는 만 2년생 개체부터 성적이형이 나타났으며, 당년생 치어와 만 1년생 개체에서는 성적이형이 나타나지 않았다. 산란기는 4월에서 5월이었으며, 만 2세부터 산란에 참여하였다. 주요 산란 연령은 만 3세부터였으며, 최대 생식소 도지수(GSI)는 만 5세에서 암컷 14.91, 수컷 8.96으로 나타났다.

• Fisheries and Aquatic Sciences
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• 제5권1호
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• pp.59-63
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• 2002

Swim up fry of the Nile tilapia, Oreochromis niloticus, were fed 0 or 60 mg l7-methyltestos­terone (MT) per kg feed for 30 days. Fish that had been fed 0 or 60 ppm MT for the first 30 days were subsequently fed a commercial diet for 56 weeks to evaluate growth, survival, sex ratio, body composition, gonadosomatic index and the total edible portion. Mean body weight of MT treated group and untreated group were 1.7 g and 1.1 g, respectively at the end of the treatment for 30 days $(P<0.05)$. The experiment was terminated after a total of 60 weeks, the mean body weight of the MT treated population was 1,016 g and that of the untreated population was 762g $(P<0.05)$. However, the final mean body weight of untreated males (l, 086g) was not significantly different from treated males (l,016 g), but the mean body weight of the female group was 512 g. Therefore, the reason for the lower mean body weight of the untreated group was entirely due to stunted females. The percentage fillet yield of MT treated fish$(34.6\%)$ was not significantly different from that of the untreated males $(34.4\%)$, but the untreated females were lower than those of both treated and untreated male groups $(32.4\%)$ (P<0.05). There were no significant differences in the percentage of the all edible portion (AP) between MT treated and untreated males, but females were lower than males. Females are smaller fish in size and the gonads are larger in proportion which were discarded along with the intestine this explains the observed difference. Total biomass of the two groups were 134.8kg and 104.5kg per $m^3$, respectively. The proportion of fish reaching a marketable size of over 800 g in body weight within 14 months were $78\%$ in the MT treated group and $41\%$ in the untreated group.

• 한국어류학회지
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• 제29권3호
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• pp.197-204
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• 2017

강원도 고성군 북천에서 종개 Orthrias toni의 생활사를 조사하여 생물학적 특징을 밝혔다. 성장은 수온이 $10^{\circ}C$ 이상 되는 4월부터 10월까지 빨랐으나 수온이 $10^{\circ}C$ 이하인 11월부터 이듬해 3월까지는 거의 멈추었다. 연령은 전장빈도분포도로 볼 때 산란기인 5월을 기준으로 전장 60~81 mm는 만 1년생, 82~99 mm는 만 2년생, 100~119 mm는 만 3년생, 120~140 mm는 만 4년생 이상으로 추정되었다. 암컷과 수컷의 연령별 전장 범위는 거의 동일하였고, 성비(♂/♀)는 0.73으로 암컷이 많았다. 산란기는 생식소성숙도(GSI)로 추정한 결과 5월이었으며, 이때의 수온은 $14{\sim}17^{\circ}C$였다. 생식소는 모든 연령이 성숙하였고, 연령이 높아지면서 포란수는 급격히 증가하였으며, 평균 $4,460{\pm}3,302$개였다. 성숙란의 크기는 연령과 상관없이 직경 $0.87{\pm}0.03mm$로 비슷하였다.

• 한국발생생물학회지:발생과생식
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• 제10권1호
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• pp.33-39
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• 2006

아무므불가사리의 생식소 발달과 생식주기를 밝히기 위하여 2003년 11월부터 2005년 2월까지 경상남도 고성 연안 해역에서 채집된 개체들을 대상으로 생식소 숙도지수 (GSI)의 월별변화, 생식소 발달과정 및 생식소 발달 단계별 난경 변화를 조사하였다. 생식소숙도지수의 월별 변화는 암컷과 수컷이 유사한 경향을 보였으며 암컷은 $3.88{\pm}3.04$, 수컷은 $0.87{\pm}0.57$의 값으로 3월에 연중 최대값을 가지다가 이후 서서히 감소하였다. GSI의 월별 변화와 생식소 발달의 조직학적 관찰을 근거로 생식 주기는 회복기($6{\sim}9$월), 성장기($10{\sim}1$월), 성숙기($2{\sim}3$월), 방출기($3{\sim}4$월), 퇴화 및 흡수기($4{\sim}5$월)의 연속적인 주기로 구분되었다. 아무르불가사리의 난발달 양상은 동시발달형이고 년 1회 산란하는 것으로 보인다.

• 한국발생생물학회지:발생과생식
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• 제16권4호
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• pp.279-287
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• 2012

We investigated the changes in plasma sex steroid hormones, testosterone (T), estradiol-$17{\beta}$ ($E_2$), 17,$20{\beta}$-dihydroxy-4-pregnen-3-one ($17{\alpha}20{\beta}P$), 11-ketotestosterone (11KT) and cortisol levels from ribbed gunnel, Dictyosoma burgeri in associated with annual reproductive cycle. The gonadosomatic index (GSI) of females increased from November, peaked in February and decreased rapidly from March. The GSI of males also increased from November, peaked in January and then decreased gradually. In females, $E_2$ levels increased and remained high from December to February. The levels of T showed a similar tendency and correlated ($r_s$=0.898, p<0.01) with $E_2$ levels. The levels of $17{\alpha}20{\beta}P$ increased rapidly in February ($4.78{\pm}1.01ng/ml$) and peaked in July ($5.08{\pm}0.65ng/ml$). Cortisol level was peaked in March and correlated with $17{\alpha}20{\beta}P$ levels ($r_s$=0.696, p<0.01). In males, the levels of T was peaked in January and then decreased rapidly. The levels of 11KT were remained high from October to January. On the other hand, the levels of $17{\alpha}20{\beta}P$ fluctuated during reproductive cycle. These results suggest that plasma sex steroids in ribbed gunnels have annual periodicity, and that cortisol may involve in maturation of females.

• 한국발생생물학회지:발생과생식
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• 제17권3호
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• pp.241-246
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• 2013

To effects of sex maturation in olive flounder by regulating long photoperiod, gonadal development and GTH mRNA expression in the pituitary were investigated. Photoperiod was treated natural photoperiod and long photoperiod (15L:9D) conditions from September 2011 to March 2012. The results showed that natural photoperiodic group showed a higher gonadosomatic index (GSI) than long photoperiodic group during the spawning season (March 2012). The histological analysis of ovarian tissue showed that natural photoperiod group of ovaries contained vitellogenic oocytes, but long photoperiod group of ovaries mainly contained perinucleolus staged oocyte and oil-drop staged oocytes. The FSH mRNA of olive flounder, under natural photoperiod group, showed a significantly higher expression but no significant difference under long photoperiod group. The $LH{\beta}$ mRNA showed a significantly higher expression only under natural photoperiod group. These results may suggest that long photoperiodic information regulates secretion of pituitary FSH and LH and maintain early growing stage of gonadal development in this species.

• 한국발생생물학회지:발생과생식
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• 제21권3호
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• pp.275-286
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• 2017

The purpose of this study is to investigate the differences fatty acids and hormonal parameters in the spawning and non-spawning season between the diploid and induced triploid Far Eastern catfish, Silurus asotus. The measured triploids were produced by cold shock for 50 min at $4^{\circ}C$ in May 2014, the spawning season of diploid was in May, and the non-spawning season was designated in January. Estradiol and testosterone and gonadosomatic index of diploid were higher than those of induced triploid in spawning season (P<0.05), and those of diploid in spawning season were higher than non-spawning season. On the other hand, thyroid stimulating hormone and thyroxine of induced triploid were higher than those of diploid in spawning season (P<0.05). Erythrocyte count of diploid was higher than that of induced triploid in spawning season and non-spawning seasons. Mean corpuscular volume and mean corpuscular hemoglobin of induced triploid were higher than those of diploid in both seasons (P<0.05). Percentages of total saturated fatty acids and n-3 polyunsaturated fatty acids of induced triploid were higher than those of diploid in spawning season, but those of diploid were higher in non-spawning season (P<0.05). Percentages of total mono unsaturated fatty acids and total n-6 polyunsaturated fatty acids of diploid were higher than those of induced triploids in spawning season, while those of induced triploid in non-spawning season were higher (P<0.05). Therefore, induced triploids in the spawning season tend to concentrate on growth and lipid-synthesization, whereas, diploids concentrate on reproduction and gonadal maturation rather than on growth. In non-spawning season, growth and lipid-synthesization were not significantly different between diploid and induced triploid.

• 수산해양기술연구
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• 제48권3호
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• pp.217-226
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• 2012

Reproductive ecology of the sharp toothed eel, Muraenesox cinereus was investigated based on the samples captured in southern Korean waters from January 2010 to December 2011. Gonadosomatic index began to increase in April, and reached maximum between July to August. After spawning it began to decrease from October. Reproductive season was estimated to April-September, with peak in July. Fecundity was proportional to the size of the female, with the clutch size varying from 56,000 eggs in the smallest female (anal length, 27.0cm) to 1,400,000 eggs in the largest (anal length, 49.5cm). Size at 50% sexual maturity ($AL_{50}$), determined from mature females, were 21.9cm. Annual reproductive cycles of this species could be divided into four successive stages; immature stage (October-February), maturing stage (March-May), mature stage (June-August) and spent stage (August-October).

• 수산해양기술연구
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• 제45권4호
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• pp.243-250
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• 2009

Maturation and spawning of the jack mackerel, Trachurus japonicus was investigated based on the samples captured in the coastal waters around Jeju Island from January 2007 to December 2008. Gonadosomatic index began to increase in March, and reached a maximum between April to June. After spawning it began to decrease from August. Reproductive season was estimated to March-July, with peak in April. Fecundity was proportional to the size of the female, with the clutch size varying from 33,493 eggs in the smallest female(FL=27.0cm) to 627,061 eggs in the largest(FL=40.6cm). Size at 50% sexual maturity(FL50), determined from mature females, was 26.6cm FL. Annual reproductive cycles of this species could be divided into six successive stages; immature stage(September-December), nucleolus stage(January-February), yolk vesicle stage(February-March), vitellogenic stage(March-April), ripe stage(April-July) and spent stage(July-September).