• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.2
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• pp.129-138
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• 2013

This study investigated the taste and nutritional properties of domestic mottled skate Beringraja pulchra as affected by the area caught, sex, and weight. Regardless of these three parameters, free amino acids comprised the main factor affecting taste in all B. pulchras. Taste values for B. pulchra ranged from 2.24 to 3.61, which were much lower than values for other fish. The total amino acid content in B. pulchra ranged from 18.82 to 21.34 g/100 g, similar to values in other fish. The major amino acids affecting both the taste value and total amino acid in B. pulchra were glutamic acid, aspartic acid, and lysine. Mineral content in B. pulchra was as follows: calcium, 252.7-288.3 mg/100 g; phosphorus, 248.2-269.3 mg/100 g; potassium, 345.9-389.5 mg/100 g; magnesium, 24.1-26.7 mg/100 g; and iron, 0.4-0.7 mg/100 g. Based on the results of free amino acid and taste value (used as an indicator to evaluate taste), and total amino acid and minerals (used as an indicator to evaluate nutritional value), the taste and nutritional properties of B. pulchra were not influenced by the area caught or weight, but were affected by the sex of the fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.3
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• pp.275-283
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• 2015

This study compared the sensory and nutritional characteristics of mottled skate Beringraja pulchra caught off Ulleung Island (U-MS), Korea, with those caught off Daecheong Island (D-MS). Based on their trichloroacetic acid-soluble nitrogen content, free amino acid content, and taste value, the taste of intermediate weight female U-MS was superior to that of both other U-MS and D-MS. The urea content of U-MS was higher in females than males and increased in the order heavy>intermediate>light individuals. There was, however, no difference in urea content between U-MS and D-MS. The taste and flavor characterization results suggest that the level of ammonia, which was converted from urea, influenced the quality of fermented U-DS. With the exception of the light U-DS, the other U-MS exhibited no difference in terms of hardness. The total amino acid content of U-MS was higher in females than males and increased in the order intermediate > heavy > light individuals. The total amino acid content of U-MS was also higher than that of D-MS. The major amino acids of all MSs were aspartic acid, glutamic acid, leucine, and lysine.

• Korean Journal of Ichthyology
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• v.30 no.4
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• pp.232-237
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• 2018

The feeding habits of Beringraja pulchra were studied using 203 specimens collected from February 2017 to March 2018 in the coastal waters of Incheon, Korea. The size of B. pulchra ranged from 31.1 to 77.7 cm in disc width (DW) and the stomachs of 16 specimens were empty. B. pulchra was a carnivore that mainly consumed fishes and shrimps, but also ate various benthic crustaceans and other invertebrates with small amounts. The main prey items in the diets of shrimps and fishes were Crangon hakodatei and Ammodytes personatus, respectively. The proportion of fishes in prey items increased with size-related while that of shrimps decreased. With increasing disc width of B. pulchra, the mean number of preys per stomach (mN/ST) and the mean weight of preys per stomach (mW/ST) were increased.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.2
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• pp.227-234
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• 2015

To obtain geographical range and growth-kinetics parameters of mottled sake (Beringraja pulchra) populations in the Yellow Sea, three mark-recapture experiments were carried out. Overall, 991 tagged individuals were released, and 4.1% of them were recaptured with the mean release period of 339 d (range, 8-1,420 d) and the mean growth rate of $1.4cm\;mon^{-1}$ (female, $1.5cm\;mon^{-1}$; male $1.3cm\;mon^{-1}$). In the first experiment, 667 individuals were released at Heuksan Island from April to June, 2007-2009, and 30 individuals were recaptured mainly at the north and the north-east coasts of the island, indicating absence of migration to the south of the island. In the second experiment, 323 individuals were released at several fishing grounds scattered in the Yellow Sea in 2010-2013, and 11 individuals were recaptured at points deviated to all directions from the releasing points. As the last, one individual was released with pop-up satellite archival tag at a costal point ($34^{\circ}37.2$'N, $124^{\circ}59.3$'E) off Hong Island on May 21, 2010. The tagged individual migrated to a north-east location ($35^{\circ}50.4$'N, $126^{\circ}03.6$'E) of Eocheong Island by Aug. 25, 2010. The data archived for the three months in the tag indicated that the migration path had depths of 48-80 m and temperature of $12.6-14.4^{\circ}C$. The results indicated that mottled sake populations had a localized habitat ranges at the north of Heuksan Island and the west of Hong Island while growing at the rate of $1.4cm\;mon^{-1}$.

• Journal of Microbiology and Biotechnology
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• v.30 no.8
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• pp.1195-1206
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• 2020

Beringraja pulchra, Cham-hong-eo in Korean, is a mottled skate which is belonging to the cartilaginous fish. Although this species is economically valuable in South Korea as an alkaline-fermented food, there are few microbial studies on such fermentation. Here, we analyzed microbial changes and pH before, during, and after fermentation and examined the effect of inoculation by a skin microbiota mixture on the skate fermentation (control vs. treatment). To analyze microbial community, the V4 regions of bacterial 16S rRNA genes from the skates were amplified, sequenced and analyzed. During the skate fermentation, pH and total number of marine bacteria increased in both groups, while microbial diversity decreased after fermentation. Pseudomonas, which was predominant in the initial skate, declined by fermentation (Day 0: 11.39 ± 5.52%; Day 20: 0.61 ± 0.9%), while the abundance of Pseudoalteromonas increased dramatically (Day 0: 1.42 ± 0.41%; Day 20: 64.92 ± 24.15%). From our co-occurrence analysis, the Pseudoalteromonas was positively correlated with Aerococcaceae (r = 0.638) and Moraxella (r = 0.474), which also increased with fermentation, and negatively correlated with Pseudomonas (r = -0.847) during fermentation. There are no critically significant differences between control and treatment. These results revealed that the alkaline fermentation of skates dramatically changed the microbiota, but the initial inoculation by a skin microbiota mixture didn't show critical changes in the final microbial community. Our results extended understanding of microbial interactions and provided the new insights of microbial changes during alkaline fermentation.

• Development and Reproduction
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• v.17 no.3
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• pp.247-255
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• 2013

The gonadsomatic index (GSI) of mottled skate was the highest in April, GSI and HSI showed a reverse phase for its reproductive cycle. The fish had one pair of egg capsules, having 1 to 7 fertilized eggs, and spawned all the year round. When surveying the reproductive characteristics of females over 63 cm in disc width, we found the spawning peak was between April to June, and the appearance ratio of egg capsules was the highest in May (32.1%). The eggs were hatched at $8^{\circ}C$, $13^{\circ}C$, $18^{\circ}C$, water temperature (12.8 to $24.2^{\circ}C$), and the best hatching temperature was $18^{\circ}C$. The number of fish hatched was 4 to 5 fish/egg capsules, and the hatching rate was 100%. The sex ratios of hatching larvae were 45.5% female and 54.5% male. Therefore this study will provide fundamental data and information for artificial reproduction of the mottled skate.

• Korean Journal of Ichthyology
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• v.26 no.4
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• pp.295-302
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• 2014

Mottled skates, Beringraja pulchra, mainly found in the Yellow Sea were caught by otter trawl at 30 stations from 2002 to 2013 to identify the distribution patterns and ecology of the fish in the eastern Yellow Sea. A total of 442 individuals of mottled skate were caught at the 112 hauls of the total 892 hauls. The fish was widely distributed in the entire survey area in spring and autumn, and mainly caught in the northern offshore in summer and in the southern part in winter. The under-yearlings of the mottled skate were mainly caught in the offshore in spring and autumn. The mottled skates were found at the temperature ranges of $3.8{\sim}14.5^{\circ}C$, and the salinity of 31.2~34.2. The catch data of the fish suggested that water temperature be a critical factor for the distribution with the optimal ranges of $5{\sim}14^{\circ}C$. Salinity and water depth were not critical as much as the water temperature for the distribution of the mottled skates in the Yellow Sea. Also, the annual fluctuations of the fish catch were reviewed using the catch data from korea fisheries cooperative and national statistics from 1991 to 2009.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.3
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• pp.213-222
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• 2020

Species composition and seasonal variations of fish in the Five West Sea Islands in Korea, were investigated by using otter trawls and bongo nets from 2014 to 2015. During the surveyed period using an otter trawl, a total of 53 species, 147,253 ind./㎢ and 2,721,296 g/㎢ of fish were collected by otter trawls. The individual dominant species were Chaeturichthys stigmatias (30.3%), Coilia nasus (18.2%), Engraulis japonicus (12.3%), and Setipinna tenuifilis (12.2%). Moreover, the biomass dominant species in biomass were Liparis tanakae (21.3%), Beringraja pulchra (18.5%), Engraulis japonicus (8.3%) and Okamejei kenojei (8.1%). Eggs by bongo nets included 1,748 ind./1,000 ㎥ of Engraulis japonicus and 64,691 ind./1,000 ㎥ of unidentified species. A total of 15 species and 2,015 ind./1,000 ㎥ of fish larvae were collected, and the dominant species were Johnius belengerii and Pholis fangi.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.3
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• pp.245-251
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• 2013

This study was conducted to compare quality characteristics of imported skate rays. The moisture content was higher in imported skate rays than in domestic mottled skate, while the protein content displayed a contrasting pattern. From measurements of the volatile basic nitrogen content, pH, viable cell counts, and urea and ammonia contents, the freshness of skate rays imported from Chile, Canada and Uruguay was considered to be inferior to domestic mottled skate, while the freshness of skate rays imported from the USA was similar. The measurement of physicochemical properties revealed that four kinds of imported skate rays were of inferior quality, as compared to domestic mottled skate.