Background: The biological information of fish, which include reproduction, is the prerequisite and the basis for the assessment of fisheries. Methods: The aim of this work was to know the reproductive biology with the first sexual maturity (TL50) and the spawning period for 58 mainly fish species in the waters around La Réunion Island (Western Indian Ocean). Twenty families belonging to the Actinopterygii were represented (acanthuridae, berycidae, bramidae, carangidae, cirrhitidae, gempylidae, holocentridae, kyphosidae, labridae, lethrinidae, lutjanidae, malacanthidae, monacanthidae, mullidae, polymixiidae, pomacentridae, scaridae, scorpaenidae, serranidae, sparidae; 56 species; n = 9,751) and two families belonging to the Elasmobranchii (squalidae, centrophoridae; 2 species; n = 781) were sampled. Between 2014 and 2022, 10,532 individuals were sampled covering the maximum months number to follow the reproduction periods of these species. Results: TL50 for the males and the females, respectively, ranged from 103.9 cm (Acanthurus triostegus ) to 1,119.3 cm (Thyrsitoides marleyi ) and from 111.7 cm (A. triostegus ) to 613.1 cm (Centrophorus moluccensis ). The reproduction period could be very different between the species from the very tight peak to a large peak covered all months. Conclusions: Most species breed between October and March but it was not the trend for all species around La Réunion Island.

연구는 기름가자미의 성비, 군성숙도 및 주 산란기에 관한 정보를 얻기 위해 수행하였다. 성비 (암:수)는 1:0.54 (n=189:103, 암컷 64.7%)였으며, 전장이 증가함에 따라 암컷의 비율이 높아지 는 경향을 보였다. 난모세포 발달패턴은 동일 난소 내에서 여러 단계의 난모세포군이 확인되 는 난군동기발달형이었다. 로지스틱 회귀모델에 의해 분석된 50% 성숙 전장은 암, 수 각각 28.51 cm과 30.49 cm였다. GSI는 암, 수 각각 4월과 3월에 가장 높았으며, 주 산란기는 4-5월 로 분석되었다.

Maturity and spawning of the pointhead flounder, Hippoglossoides pinetorum were investigated on the basis of samples collected in the coastal waters off Gangwon-do, East Sea from January 2012 to December 2013. The average total length of H. pinetorum was 25.0 cm and 21.9 cm for females and males, respectively. The spawning period was from May to July according to monthly changes gonadosomatic index (GSI) and maturity stages. The spawning period in Gangwon-do was delayed relatively to that in Gyeongbuk-do. The mature egg diameter ranged between 300-700 ㎛. The relationship between TL and fecundity (F) was F = 63.574 TL - 1471.3 (R2=0.7603), that is, the larger total length, the more fecundity H. pinetorum had. We estimated that the TLs at 50% group maturity were 25.6 cm for females and 19.9 cm for males. The spawning ecology by sea area should be considered efficient resource management for H. pinetorum. Furthermore, it is necessary to study more on the relationships among growth, maturity and water temperature variations in the East Sea.

Maturity and spawning of the giant Pacific octopus, Octopus dofleini was investigated based on the samples collected in the coast of Gangwondo, East Sea, from January to December in 2009. Individuals of mature stage had a higher occurrence rate from February toMay, and gonadosomatic index (GSI) also showed a higher value from February toMay than the other months. For that reason, the spawning period was estimated from February to May with the main spawning period from March to May. The total number of eggs in the fecundity (F) ranged from 9,045 in 11.0 kg (TW) to 148,682 in 16.5 kg (TW), which was proportional to total weight (TW), and the relationship between total weight and fecundity was F=0.185×TW2.238 (R2=0.389). The total weight at 50% group maturity (TW0.5) of female was estimated to be 12.2 kg.

This study investigated purplish Washington clam, Saxidomus purpuratus on its gonadal development, reproductive cycle and shell length (age) at 50% female group maturity from January to December 2011 in Jinhae Bay, Korea. This species is dioecious. The gonad index (GI) began to increase in January, reached the maximum value in May and to decrease in June, reached the minimum value in September then to increase slowly in October again. The reproductive cycle of the clams can be divided into five successive stages: the early active stage (Ea, from February to March), the late active stage (La, from January to March and October to December), the ripe stage (R, from January to May), the spawning stage (S, from June to December) and the degenerative and inactive stage (Ia, from January to February and November to December). The spawning periods were from June to December and the main spawning periods were from July to October. The shell length at 50% female group maturity (SL50) was estimated to be 63.6 mm, which can be converted as sexual maturity age of 2.2 year.

자연 생물자원 관리를 위해, 광양만내 인공적으로 폐쇄된 슬라그 적재장내에 서식하는 암컷 피뿔고둥 Rapana venose(Valenciennes)를 대상으로 조직학적, 육안적 관찰에 의해 군성숙도, 성비, 산란빈도, 난낭 산출 및 포란수를 조사하였다. 암컷 개체들의 군성숙도(%)는 각고 7.1~8.0 cm의 경우 51.6%이었고, 9.1 cm 이상인 개체들의 경우는 100%이었다. 개체당 총난낭수 및 난낭내의 평균 난수는 각각 192~382개와 500개