• Development and Reproduction
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• v.23 no.3
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• pp.239-253
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• 2019

We investigated the physiological responses of the river puffer, Takifugu obscurus, the tiger puffer, T. rubripes, a hybrids of the two (river puffer${\times}$tiger puffer) and a hybrid triploids to acute changes of salinity from 30 psu to 0 psu and from 0 psu to 30 psu. The blood and plasma factors of each species were elevated for 48, 72, or 96 hrs, and thereafter decreased due to hyper-osmoregulation and hypo-osmoregulation. In hyper-osmoregulation and hypo-osmoregulation, the cortisol concentration of river puffer, hybrids, hybrid triploids and tiger puffer increased for 12 or 48 hrs, and decreased thereafter. Chloride cells in the gill filaments of each species increased with increasing salinity, and melano-macrophages in the kidney tissue of each species increased with decreasing salinity. In conclusion, the hematological and stress responses of the hybrids were between those of the river puffer and tiger puffer, and the hematological responses of the hybrid triploids were higher than those of the other groups. The stress response of the hybrids was more sensitive than that of the hybrid triploids. In all groups, the histological responses of kidney in hyper-osmoregulation were more sensitive than those in hypo-osmoregulation.

• Korean Journal of Environmental Biology
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• v.39 no.1
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• pp.6-15
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• 2021

Various biometric and geometric measures were used to discriminate between the morphologically similar river puffer, Takifugu obscurus, tiger puffer, T. rubripes, their hybrids, and their triploid hybrids. The hybrids and triploid hybrids had greater anal fin width, nostril width, and snout length than the parental species (p<0.05). However, they had less caudal peduncle depth, inter-orbital width, head length, and head width(p<0.05). The morphometric and meristic characteristics of the hybrids and triploid hybrids were either intermediate between the parental species or more similar to those of one parental species. However, the external morphology of the hybrids and triploid hybrids was predominantly maternal. The triploid hybrids had asymmetry in the fin rays and gill raker numbers. This study identified phenotypic characteristics by distinguishing the morphological variables of river puffer, tiger puffer, their hybrids, and their triploid hybrids.

• Development and Reproduction
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• v.21 no.2
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• pp.181-191
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• 2017

A comparison of the growth, hematological values, fatty acids, and gonadal and growth hormonal changes of river puffer, Takifugu obscurus, tiger puffer, T. rubripes, their hybrids (river puffer ${\times}$ tiger puffer) and hybrid triploids was performed during 3 months of their early growth period. Several features were observed during these 3 months: hybrids showed the highest levels of specific growth rate, 1.48%; hybrid triploids showed the smallest change in viscera fat (P<0.05), but GSI was not significantly different among groups (P>0.05). Considering hematological parameters, hybrid triploids had increased mean corpuscular volume and mean corpuscular hemoglobin (P<0.05), but other parameters were not significantly different between groups (P>0.05). With respect to fatty acids, puffer fish, hybrids and hybrid triploids contained fatty acids such as SFAs, MUFAs, n-3 PUFAs and n-6 PUFAs. There were significantly different amounts of total fatty acids between groups (P<0.05), however, rates of changes in fatty acids did not differ significantly between groups (P>0.05). Gonadal hormone (estradiol and testosterone) changes in the river puffer and tiger puffer were significantly higher than that observed in hybrids and hybrid triploids. The hybrids and tiger puffers had higher amounts of growth hormone (thyroid stimulating hormone and thyroxine) than the hybrid triploids and river puffers (P<0.05).

• Journal of Aquaculture
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• v.12 no.1
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• pp.1-5
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• 1999

To obtain fundamental data for sperm cryopreservation in river puffer (Takifugu obscurus), the proper conditions of cryopreservation were investigated. In the sperm cryopreservation of river puffer, marine fish Rinser's solution (MFRS) was found to be good diluent and dimethyl sulfoxide (DMSO) was proved to be superior to glycerol as a cryoprotectant. The highest fertilization rate was achieved when river puffer sperms were cryopreserved with MFRS adding 5％ DMSO.

• Development and Reproduction
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• v.23 no.1
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• pp.21-34
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• 2019

The effects of the anaesthetic agents, clove oil and mixture of clove oil with lidocaine-HCl were evaluated on river puffer, Takifugu obscurus and tiger puffer, T. rubripes. Anaesthesia times of clove oil were affected by water temperature ($20^{\circ}C$, $24^{\circ}C$, and $28^{\circ}C$) and salinity (10, 20, and 30 ppt). Anaesthesia times of mixed samples were significantly similar with regard to exposure and recovery times, and all samples satisfied anaesthesia criteria (exposure time within 3 min and recovery time within 5 min) under the various temperatures and salinities, and the lowest to highest concentration of anaesthetics (p<0.05). Both species river puffer and tiger puffer had short exposure time with a high anaesthesia dose, high temperature ($28^{\circ}C$) and intermediate salinity (20 ppt), and were highly affected by temperature and salinity (p<0.05). The mixed anaesthetics had rapid exposure times and long recovery times in contrast to the effects of clove oil. Cortisol concentrations under the conditions of various clove oil dosages, salinity, and temperature for both species increased until 12 hrs after recovery from anaesthesia (p<0.05). After 12 hrs, cortisol concentrations decreased until after 48 hrs (p<0.05). During the simulated transportation of both species, control and sedated clove oil groups (5 ppm) were measured for water parameters, dissolved oxygen (DO), $CO_2$, respiratory frequency, $NH_4{^+}$, and pH for 6 hrs in 1 hr intervals. Water parameters of sedated groups and controls were significantly different after 2 hrs (p<0.05).

• Journal of Aquaculture
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• v.18 no.1
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• pp.45-51
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• 2005

The optimum salinity and the effects of rapid salinity change on oxygen consumption and ammonia nitrogen excretion were examined in River Puffer Takifugu obscrus (total length 9.5$\pm$0.9 cm, total weight 18.7$\pm$5.4 g). Fish examined at the different transfer medium salinity (2, 12, 22 and 32 psu) after 2 months of acclimation period at each salinities. The routine metabolic rates of River puffer are shown as parabola equation, $Y=-0.0873X^2+0.6384X-0.690$ for oxygen consumption and $Y=-2.1667X^2+7.1672X+31.999$ for ammonia nitrogen excretion with the salinity medium at 2, 12. 22 and 32 psu. The oxygen consumption and ammonia nitrogen excretion of River puffer trans-ferred to the low salinity medium (2 and 12 psu) showed significantly difference in each salinities rearing groups than to salinity of 22 and 32 psu. Fish has a diurnal rhythm in relate to feeding, it was showed that the peak of oxygen consumption appeared at 3 hours after feeding and the ammonia nitrogen excretion rate reached maximum 4 hours after feeding. These results may indicate that the optimum salinity for rearing of River puffer is 22 psu based on growth and feed conversion ratio. The rapid change of medium salinity had no effects on the oxygen consumption and nitrogen excretion in River puffer based on this experiment.

• Journal of Aquaculture
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• v.17 no.3
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• pp.221-227
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• 2004

In the present study, we investigated the effects of food and salinity on growth and survival of river puffer, Takifugu obscurus offsprings in indoor land-based tank during the early development. In the food experiment, the river puffer larvae (TL 8.7$\pm$0.1 mm, BW 20.0$\pm$3.2 mg) were fed with tubificid, Limnodrilus gotoi, water flea, Daphnia carinata, mysid, Neomysis awatschensis, Manila clam, Ruditapes philippinarum and artificial food together Artemia nauplii for 30 days, and the growth and the survival of larvae were investigated. In the salinity experiment, the river puffer larvae and juvenile at three stages (Stage I: TL 5.8$\pm$0.4 mm; Stage II: TL 12.0$\pm$0.2 mm, Stage III： TL 44.5$\pm$0.7 mm) were supplied with Artemia nauplii, water flea and/or artificial food and were reared in 0, 10, 20 and 30 psu at respective stages. The results shows that the growth rates of larvae feeding with artificial food and tubificid together Artemia nauplii were higher than those of larvae in other groups, but the survival rates of larvae feeding with water flea and mysid together Artemia nauplii were higher than those of larvae in other groups. In salinity, the results shows that the growth and survival rates of offsprings were significantly higher in 10∼20 psu than those in 0 and 30 psu at Stage I and n. At Stage III, the growth and the survival rates were the highest in 20 psu, but the lowest in 0 psu. However, it should be noted that the rates in 0 and 30 psu were significantly enhanced at Stage III in comparison with those at Stage I and II. Therefore, it is concluded that river puffer, T. obscurus is euryhaline marine species, which can normally grow and live at salinities from 0 to 30 psu, and that a combinative supplement with Artemia nauplii and water flea, D. carinata may confer an advantage on growth and survival of the river puffer offsprings in indoor land-based tank.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.4
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• pp.383-389
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• 2014

An 8-week feeding trial was conducted to determine the apparent dry matter and protein digestibility of seven different dietary protein sources by juvenile river puffer Takifugu obscurus. Eight diets containing white fish meal (WFM), brown fish meal (BFM), squid liver powder (SLP), krill meal (KM), leather meal (LM), soybean meal (SM), or fermented soybean meal (FSM) were prepared by mixing a basal diet (BD) with one of the seven test ingredients at a ratio of 7 to 3. Fish averaging $10.8{\pm}0.04g$ were fed the experimental diets in triplicate groups. The apparent dry matter digestibilities of BFM, WFM, FSM, SLP, LM, SM, and KM were 80, 78, 72, 67, 56, 55, and 54%, respectively, while the corresponding apparent protein digestibilities were 96, 96, 93, 92, 89, 88, and 86. The weight gain of fish fed BFM was significantly greater than that of fish fed SM or LM (P<0.05), while it was not significantly different from that of fish fed the BD, WFM, FSM, BFM, SLP, or KM. These results indicated that WFM, BFM, FSM, and SLP are potentially good protein sources for replacing fish meal in river puffer feed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.243-246
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• 1999

To obtain the basic data for the preservation of river puffer (Takifugu obscurus) sperm, experiments were carried out on the physico-chemical properties and cold storage of milt. The average number of sperm and spermatocrit in milt stripped were $1.13\pm0.34\times10^{10}/ml$ and 64.8$\pm$1.4, respectively. Osmolality of seminal fluid was 266$\pm$2 mOsm/kg, Total protein and total lipid from sperm were higer than that from seminal fluid. $Ca^{2+}$ and $Na^{+}$ concentrations were higher in the seminal fluid than in the sperm, while $Mg^{2+}$ and $K^{+}$ concentrations were lower in the seminal fluid. When sperm of river puffer were preserved in $0\pm0.5^{\circ}C$ with various diluents for 16 days, fertilization rate was $0\~0.7\%$. It suggested that cold storage of river puffer sperm was detrimental to sperm fertility.

• Journal of Aquaculture
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• v.20 no.4
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• pp.270-277
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• 2007

White spot syndrome virus (WSSV) which is the most serious threat to cultured shrimp around the world has given enormous economic damages to shrimp culture industry every year since it was found from the shrimp ponds in the west coast of the South Korea in 1993. WSSV has strong infectivity as well as virulence and it can be rapidly transmitted among shrimps in ponds by cannibalism of infected ones. Polyculture of shrimps with carnivorous fish has been applied in commercial shrimp farms to suppress or delay the viral outbreak because the fish may selectively eat the moribund shrimps infected by virus. To determine the selective predatory effect of a carnivorous fish, river puffer Takifugu obscurus on white shrimp Litopenaeus vannamei, polyculture trials in laboratory scale of WSSV-infected and non-infected shrimps with river puffer were conducted in concrete round tanks of $28.26\;m^2$ in surface area as followings: 1) juvenile shrimps (B. W. 0.62 g) with 5 months old puffer (B. W. 11.60 g) cultured for 8 days, and 2) sub-adult shrimps (B. W. 6.84 g) with 16 months old puffer (B. W. 85.82 g) cultured for 5 days in order to know the effects according to size difference of cultured animals. In polyculture of juvenile shrimp with 5 months old puffer, survival rates of infected and non-infected shrimps were 46.0% and 89.1% respectively and in that of sub-adult shrimp with 16 months old puffer those were4% and 48% respectively. The results showed that puffer tends to selectively prey on virus infected shrimps among infected and non-infected ones in a limited space with although there is difference in predatory rate with age and density of animals. Regardless of different densities and ages of animals as well as health condition of shrimps, however, there were low differences in daily biomass of shrimp consumed per kg body weight of puffer. This finding suggests that puffer preys on healthy shrimps when moribund shrimps were not sufficient. Therefore, farmers should consider the total biomass of puffer as well as density and stocking time when they stock puffer into shrimp ponds for polyculture.