• Development and Reproduction
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• v.1 no.2
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• pp.173-180
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• 1997

This study has been conducted to investigate the molting behavior and the effects of rearing temperature and day length on molting in the behavior and the effects of rearing temperature and day length on molting in the giant freshwater prawn, Macrobrachium rosenbergii reared in the laboratory. The results obtained were summarized as follow: 1. After pre-spawning molting, the protopodites of 1st, 2nd, 3rd, and 4th except 5th pleopod bore new breeding setae which conserve eggs in the brooding chamber and the basis of 3rd, 4th, and 5th pereiopods bore new breeding dresses which transport the ovulated eggs into the brooding chamber. 2. Adult females reared in 27.5-$29.4^{\circ}C$ molted 10-12 times per year at interval of 27-35 days, of which four or six moltings were common molting for growth and another four or five moltings were pre-spawning molting for spwaning and brooding. In winter season, pre-spawning molting did not happen to most of adult females in spite of the same temperature. 3. Duration of intermolt cycle was 31-38 days and 26-30 days at 25.3- $26.5^{\circ}C$ and 28.7- $30.4^{\circ}C$ of rearing temperature, respectively.

• 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.

• Korean Journal of Ichthyology
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• v.33 no.1
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• pp.8-14
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• 2021

Spawning behavior of the endangered Korean fish, Microphysogobio koreensis, was investigated in the Seomjingang (river), Imsil-gun, South Korea, during the spawning season, April to May 2012. The mating system of M. koreensis, a broadcast spawner, was a primitive spawning mode, and involved one male and one female, unlike group spawning fishes. Spawning behavior of M. koreensis in the wild were observed in eight patterns as resting, male chase, body beating, parallel swim, female withdrawal, male competition, spawning and not guard while spawning behavior in the glass tank were verified in six patterns as resting, male chase, body beating, parallel swim, spawning and not guard. In particular, a behavioral attempt of the pre-spawning stage showed more frequently in the wild than in the glass tank. We assume that difference of spawning behavior might be implication on behavioral restrictions in small and narrow indoor glass tank.

• Development and Reproduction
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• v.1 no.2
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• pp.181-187
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• 1997

This study has been conducted to investigate the mating behavior, time sequence of mating and time limit with which female can fulfill spawning and brooding after pre-spawning molting in the giant fresh-water prawn, macrobrachium rosenbergii reared in the laboratory. the results obtained were summarized as follows. Mating happened spontaneously as the following sequences: courting gesture, seizure of female by male, mounting, turning of female, copulation. The entire mating lated approximately seven minutes. The endopodite of 2nd pleopod of male bore the appendix masculins whcih are male's secondary sex characteristic. cinciulli was formed at the distal portion of appendix interna which are on the upper portion of appendix masculins and helped stabilizing the connection of each side of 2nd pleopod during mating. After the connection of each side of 2nd plepod was fixed on the posterior portion of the thoracic sternum in female, a gelatinous spermatophore that emitted at the basipodite of 5th pereiopod during courting gesture was deposited on the ventral groove of 2nd, 3rd, 4th and 5th pereiopod. time limit which female can fulfill copulation and brooding was from 3 hours to 15 hours after pre-spawning molting.

• Korean Journal of Ichthyology
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• v.34 no.1
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• pp.57-63
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• 2022

On April. 2016, the anadromous icy goby caught at Shinbong-cheon, Tongyeong shi, Gyeongsangnam-do transported to the laboratory of Korea Institute of Ocean Science and Technology (KIOST) and observed spawning behavior and egg development and larvae. In aquarium, males make the nest under stone and waiting female entering. Fertilized eggs attached under the stone in the nest. Male protected the fertilized eggs until hatching. The size of the club-shaped eggs were 3.2~3.4 mm in the major axis and 0.6~0.8 mm in minor axis (n=10). The eyed eggs were hatched after 168 hrs in a range of water temperatures (18.0~20.0℃). The total lengths of newly hatched larvae were 4.1~4.4 mm (n=5) and these larvae had 32~33 (12~13+20) myotomes and transparent oval yolk. Three days after hatching, the pre-larva (4.9 mm in total length) has opening mouth and rectum. Post-larva with 5.2 mm total length have melanophore on air bladder, rectum, base of membranous caudal fin and 9~10 melanophores ventral row on the tail.

• Development and Reproduction
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• v.20 no.1
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• pp.31-40
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• 2016

This study was conducted in order to examine the egg development in red spotted grouper, Epinephelus akaara and the morphological development of its larvae and juveniles, and to obtain data for taxonomic research. This study was conducted in June 2013, and 50 male and female fish were used for the study. One hundred ${\mu}g/kg$ of LHRHa was injected into the body of the fish for inducing spawning, and the fish were kept in a small-sized fish holder ($2{\times}2{\times}2m$). Eggs were colorless transparent free pelagic eggs, 0.71-0.77 mm large (mean $0.74{\pm}0.02mm$, n=30), and had an oil globule. Hatching started within 27 h after fertilization. Pre-larvae that emerged just after hatching were 2.02-2.17 mm in total length (mean $2.10{\pm}0.11mm$), their mouth and anus were not opened yet, and the whole body was covered with a membrane fin. Post-larvae that emerged 15 days post hatching were 3.88-4.07 mm in total length (mean $3.98{\pm}0.13mm$), and had a ventral fin with two rays and a caudal fin with eight rays. Juveniles that were formed at 55 d post hatching, were 31.9-35.2 mm in total length (mean $33.6{\pm}2.33mm$), with red color deposited over the entire body, and black chromophores deposited in a spotted pattern. The number of fin rays, body color, and shape were the same as that in the adult fish.

• Journal of Aquaculture
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• v.4 no.1
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• pp.31-66
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• 1991

This paper deals with the reproductive ecology e.g., number of the pre-spawning moults, morphological characteristics of the pre-spawning moult the common moult, daily ration druing a molting cycle mating behavior, structures of spermatozoa and spermatophore, structure of vas deferens, mechanisms of the oviposition and brooding into the egg-chambers, a suitable time for the artificial mating and fertilization, time sequence of the oviposition and brooding into egg-chambers from the copulation, responses to temperature and chlorinity on the egg development and hatching, effect of temperatures on duration of egg development, physical mechanism of the egg hatching, to make an attempt for the artificial spawning and brooding to establish a suitable system of the artificial seedling-production for the aquaculture. 1. Females molted commonly $8{\~}10$ times at an interval of $17{\~}18$ days at $28^{\circ}C,\;3.26\~4.35\%_{\circ}$ while the prespawning moltings were $4{\~}5$ times at an interval of $13{\~}14$ days. The suitable state for artificial copulation was within 14 hours elapsed from the prespawning moltings (most suitable state was within 8 hours). Males discharged a gelatinous spermatophore and placed it on the females sternum during copulation. Oviposition was seen $6{\~}17$ hours after copulation. External fertilization was considered to take place at oviposition. Fertilized eggs held in egg-chambers forming between pleopods were about $5000{\~}6000$ in females those sizes about 6.5 cm in body length. 2. Eggs immediately after oviposition were elliptic shape, measuring $0.58{\times}0.48$ mm up to hatching. Their sizes increased with egg development and finally reached $0.85{\times}0.54$ mm up to hatching. The relationship between the long axis of the egg(Y in U) and days elapsed(X) was expressed as Y= 5.60194 + 0.007358X. The eggs performed superficial cleavage and their cleavage furrows became visible at the 4-daughter-nucleus stage. The eggs showed normal development up to hatching at water temperature range of $22{\~}30^{\circ}C$ (optimum temperature : $26{\~}28^{\circ}C$) and at chlorinity range of $0.00\~6.64\%_{\circ}$ (optimun chlorinity : $2.21{\%}_{\circ}$). The relationship between incubation period (Y in days) and water temperature(X in $^{\circ}C$) could be expressed as Y= 50.803-1.3555X. The eggs hatched $12{\~}13$ days after oviposition at $28.0{\~}28.6^{\circ}C$ 3. The pre-spawning moltings were appreciably different in the morphologic structure from those of common moltings. Breeding setae and dresses were formed on the thoracic regions, abdominal epimerae and the bases of the first to fourth pleopods in order to prepare and support oviposition, transfering and supporting eggs in egg-chambers up to hatching. These supplementary breeding organs were observed only at reproductive seasons.