• Development and Reproduction
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• v.18 no.1
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• pp.25-31
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• 2014

This study was investigated spawning behavior, structure of egg masses and egg development in Aplysia kurodai inhabiting the coastal waters of Jeju Island, Korea. The mating and courtship behavior of A. kurodai occurred in the form of unilateral copulating with chain formation. In chain copulation, only the first animal acted as a female; the second and succeeding animals acted as males (sperm donors) to the animals in front and as females to the animals behind. The fertilized eggs were packaged in capsules that are embedded in jelly to form a cylindrical string called an egg masses. The number of capsule per cm of the egg masses was 55 to 60 capsules and each capsule within the egg masses held 15 to 25 eggs. After spawning, the egg masses were bright yellow or orange in color. This egg masses color not changed until embryos developed into trochophore stage. Thereafter, as embryo developed from trochophore stage to veliger stage the egg masses color became brownish. The fertilized eggs were spherical, with a diameter of approximately $80{\pm}1{\mu}m$ at spawning. At 5 to 6 days after spawning, the embryo developed into trochophore stage and began to rotate within the egg capsule. In the trochophore stage, the precursor of the velum, called the prototroch or prevelum, developed. At 10 days after spawning, the prevelum is transformed into the velum, and the trochophore developed into veliger stage. Between 10 to 15 days after spawning, the veligers broke out of the egg capsule, and hatched as free-swimming larvae.

• Korean Journal of Ecology and Environment
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• v.38 no.2 s.112
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• pp.207-216
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• 2005

Spawning behaviors of Squalidus gracilis majimae (Cyprinidae) were observed in the laboratory whose environmental factors such as light (D/L = 16 : 8), temperature ($20\;{\sim}\;24\;＾{\circ}C$), and dissolved oxygen (>8 mg $L^{-1}$) were quite regularly controlled. The behavioral patterns were categorized into three stages ofpre-spawning, spawning, and Post-spawning behaviors. In Particular, the pre-spawning stage was specified by 11 specific behavioral patterns of aggressive mating behaviors. During the spawning stage, the male and female performed four distinct spawning behaviors including sexual temptation, stimulation, egg spawning, and the separation, and randomly laid about 200 ${\sim}$ 300 eggs on the bottom substrates through the night. After finishing spawning, two adults separated toward their refuges and showed 3 types of post-spawning behaviors such as the resting, occasional eggs protecting, and the egg eating. The fish was identified as a partial-parental care species after the spawning.

• Development and Reproduction
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• v.1 no.1
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• pp.91-97
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• 1997

In order to study the reproductive physiology of Sand ell(Hypoptichus dybowskii) catched at kangwon-do, Wooamjin Bay, spawning and egg development were investigated in April and May, 1996. The observed spawning period was from the middle of April to the end of May with the water temperature above $8^{\circ}$C. Body size and colouration were distinguished between male and female. The type of testicular structure is lobular, and the ovary is a pair of sac-sahaped covering with a fibromuscula capsule and comprising a mature egg of average 86. The unfertilzed egg are demersal and adhesive, and their diameter were 1.65-1.95 mm. the colour of yolk is light yellow and contained a lot of tiny oil globules. The average spawned egg was 62 in sargasso weeds. Hatching was observed in 12 days after fertilization with the water temperature of 14 ${\pm}1^{\circ}$C. The average size of larva after hatching was 6.85${\pm}$0.23mm in total length, and larva were containing yolk including globule.

• The Korean Journal of Ecology
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• v.19 no.5
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• pp.477-486
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• 1996

The freshwater goby, Micropercops swinhonis ($G\"{u}nther$) was studied on the spawning behavior and egg develeopment at the two areas of Chollabukdo, Korea from March to May 1995. Egg mass attached to a layer under stones and the inner wall of waterplant, Cyperus. Spawning behavior was divided in to 1) premating stage: selecting spawning sites and formation of territory by male, 2) mating stage: enticement with zigzag-like dance and intermittant shaking of head by male and fertilization, 3) postmating stage: fanning, guarding and cleaning the nest by male. The eggs were transparent and spherical in shape, measuring $0.9\times1.4mm$ with yellowish yolk sac and many oil globules. Hatching began in about ten days after fertilization at water temperature $16~20^{\circ}C$. The newly hatched larvae were 3.8~4.0 mm in total length with 30 myomeres and their mouths and anuses were opened. Melanophores appeared at the air-bladder and the ventral side of caudal region.gion.

• 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.

• The Korean Journal of Malacology
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• v.9 no.2
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• pp.1-15
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• 1993

The reproductive ecology of the purple shell, Rapana venosa was investigated by the histological observations on depositions of the egg capsules, and hatching of larvae in the laboratory and the subtidal zone of the vicinity of piung-do, Chollabud-do, west coast of korea, for one year from June 1992 to May 1993. The results are summarized as follows:1. Rapana venosa is dioecious in sex. The ovary is composed of a number of ovarian lobules, and the testis comprises a number of ovarian lobules, and the testis comprises of gonads could be classified into 4 stages in males and 5 stages in females: 1) growing stage(in female subdivided into 2 stages of early and late growing stage). 2)mature stage. 3)spent stage or copulationstage. 4)rdcovering stage. The early growing stage in females of the purple shell was in September through February, late gorwing stage was in October to March, mature stage was in September to January, mature stage was in September to July, copulation stage was in Februaty to June and recovering stage in April to October.3. Spawning occurred 3-4 times at intervals of 1-3 days, and completed within 10 days from the beginning of spawning during the spawning season of the year.4. From the results of laboratory and field observations, egg masses are composed of a number of egg capsules, egg masses are occurred from May to late August, and in mid August depositions of egg mass in composed of 90-113 egg capsules, fecundity in an egg capsule was ranged 984 to 1,241 eggs(average 1,096 egg). Therefore, fecundity in total egg capsules spawned per individual during the spawning season is estimated as approximately 320,000 to 450,000 egges.5. The incubation period during deposition of an egg capsule to hatching larvad tood 17 days at 18.3-20.4%C(water temperature)and 1.021 (specific gravity fo sea water).

• Applied Microscopy
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• v.50
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• pp.13.1-13.7
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• 2020

We examined the morphology of fertilized egg and ultrastructures of fertilized egg envelopes of Ancistrus cirrhosus belong to Loricariidae using light and electron microscopes. The fertilized eggs formed a mass on the spawning place and were yellowish, spherical, non-transparent, demersal, adhesive, and a narrow perivitelline space. But, the adhesiveness of fertilized eggs was disappeared after spawning excluding contact parts. The micropyle with funnel shape was surrounded by 15-19 furrow lines of egg envelope in a spoke-like pattern. The outer surface of egg envelope has smooth side and inner surface of egg envelope was rough with grooves. Also, the total thickness of the fertilized egg envelope was about 32.58 ± 0.85 ㎛ (n = 20), and the fertilized egg envelope consisted of three layers, an outer adhesive electron-dense layer, a middle layer with low electron density and an inner electron-dense layer with grooves in counter structure from other most teleost. Collectively, these morphological characteristics and adhesive property of fertilized egg, and ultrastructures of micropyle, outer surface, and section of fertilized egg envelope are showed species specificity.

• The Korean Journal of Malacology
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• v.31 no.2
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• pp.113-121
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• 2015

Gametogenesis, mating behaviour and spawning of Octopus ocellatus were investigated by histological study. This species is dioecious, and showed a protandry phenomenon. Ooogenesis (in females) and spermatogenesis (in males) can be classified into 3 stages, respectively. O. ocellatus copulates in one of two ways: a male may leap upon a female, mounting her mantle, or a male may sit near the female and extend the hectocotylized third right arm toward her. Spawning occurred between April and June in females, and between March and May in males of O. ocellatus. The spawning period was once a year and the peak took place between May and June. A number of flatened follicle cells, which were attached to an oocyte, were involved in vitellogenesis in the cytoplasm of the vitellogenic oocyte (maturing oocyte), and formation of chorion membrane (secondary egg membrane) of the ovarian eggs. Fecundity per female closely related to GSI was 294-660 eggs (average, 429 eggs). The diameters of the ovarian eggs surrounded by chorion membrane were approximately in the range of 10.10-2.50 mm. Each ovarian egg laid by a female was connected to an egg string. Each egg string was 1-5.5 cm (average 3.6 cm). The total number of eggs laid by a female of this species ranged 218-314, the egg sizes were independent to the size of female adult. this species has a life mode showing some special reproductive characteristics of an annual semelparity as shown in Octopodidae species because we have never seen a female spawning a second time.

• Journal of Aquaculture
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• v.10 no.1
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• pp.17-24
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• 1997

In order to understand the spawning and larval development of Perinereis aibuhitensis for the effective seedling production, the influence of water temperature on spawning induction, egg and larval development of the worm were investigated from October 30, 1989 to October 30, 1990. Main spawning period was from July through September, and average diameter of mature eggs was $220\mu m$. The relationship between the adult weight (Wt) and the number of spawned eggs (NS) was given as follws : NS=48635.589Wt1.3044 (r=0.8572). Adult males and females died immediately after spawning. Trochophore larvae developed 12 hours after fertilization, and hatched out after 56 hours.

• Korean Journal of Ecology and Environment
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• v.34 no.4 s.96
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• pp.337-341
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• 2001

Studies were conducted to determine the effects of water temperature on the number of spawning, egg production, spawning intervals and hatching success of Chinese bleak, Aphyocypris chinensis. Adult fish were exposed to water temperatures of 19, 22, 25 and $28{\circ}^C$ for two months in the laboratory. The spawning number, egg productivity, and hatching rate increased as water temperature increased between $19{\circ}^C$ and $25{\circ}^C$. Maximum egg production and hatching rate occurred at $25{\circ}^C$, whereas the spawning intervals decreased as water temperature increased except for the treatment of $28{\circ}^C$. The shortest spawning interval observed at $25{\circ}^C$.