• Journal of Aquaculture
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• v.22 no.1
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• pp.92-99
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• 2009

Population dynamics and sexual maturity of Neomysis japonica (Ishikawa and Oshima, 1951) were investigated from a shrimp farm in Tae-an, Korea. N. japonica was collected monthly at the shrimp farm belonging to the Marine and Fisheries Research Institute, the Soonchunhyang University from October 2002 to September 2003. The proportion of female was higher than that of male. The mean carapace length of male (2.42 mm) was larger than that of female (2.31 mm). Brood size increased with increasing female body size. The size of N. japonica at 50% sexual maturity was approximately 4.4 mm. N. japonica females grew faster and reached larger size than males. The mortality rate (z) calculated by length-converted catch curves was $3.46\;yr^{-1}$. The annual recruitment pattern of N. japonica had two major peaks. Log-transformed total length was significantly related with log-transformed carapace length.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.4 no.2
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• pp.43-46
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• 1971

1. The effects of different conditions of the feedings in connection with the bottom stata on the growth rate of Penaeus orientalis have been investigated. 2. The relationships between the days (D) after hatching and the carapace lengths (L) of p. orientalis are represented by the following equations: Feeding, muddy bottom: L=0.3939D+6.8965 feeding, sandy bottom: L=0.2652D+12.2620 Nonfeeding, sandy bottom: L=0.0713D+16.0655 Nonfeeding, muddy bottom: L=0.2852D+7.8620 3. The growth rate of the carapace length of p. orientalis in the region of muddy bottom is higher than that of the carapace in the sandy bottom whether the prawns are fed or not.

• Animal Systematics, Evolution and Diversity
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• v.33 no.4
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• pp.228-234
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• 2017

The first zoeas of Nursia rhomboidalis and Pyrhila carinata were obtained from laboratory condition. They are described and illustrated for the first time. Morphological comparison with those of other Korean described species of the family Leucosiidae reveals that the zoea of N. rhomboidalis is very similar to those of Myra fugax and Arcania undecimspinosa based on characteristics of the carapace spines length, the antenna morphology, the maxilla endopod setation, and the telson, whereas, the zoea of Py. carinata coincides well with those of Philyra kanekoi and Pyrhila pisum based on characteristics of the carapace spines length, the antenna morphology, the maxilla endopod setation, and the telson. Furthermore, we find that at least two groups of zoeas exist in the Korean species of the subfamily Ebaliinae. A provisional key to the known zoeas of ten leucosiid species from Korean waters is provided.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.589-593
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• 2017

A single specimen of Kentrocapros flavofasciatus (measuring 145.9 mm in length) belonging to the family Aracanidae, order Tetraodontiformes, was collected for the first time in 2017 on Jeju Island, Korea. This specimen had isolated bony plates on a caudal peduncle, a carapace with six ridges, and a tail depth equal to its tail length. It is similar to K. aculeatus and K. rosapinto but differs from K. aculeatus in that its carapace is without spines; it differs from K. rosapinto in that the anterior end of its gill opening does not reach below the center of its eye. We propose new Korean names: Yug-gak-bok-gwa for the family Aracanidae, and Hwang-Jul-yug-gak-bok for the species K. flavofasciatus.

• Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.111-117
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• 2011

The population dynamics of Pandalus gracilis was investigated in the southeastern coastal area of Korea between May 1998 and April 2000. Of the 4,127 specimens, 57% were identified as females, 39% as males, and 4% as transitional hermaphrodites. The number of females was greater than that of males and transexuals. A significant correlation was observed between the number of transitional hermaphrodites and ambient seawater temperature. Growth parameters were estimated using the modified von Bertalanffy growth function model incorporating seasonal variation in growth using the program ELEFAN. Females grew faster and reached a larger size-at-age than males (K=0.65/y and $L_{\infty}$=17.86 mm carapace length [CL] for females; K=0.51/y and $L_{\infty}$=14.70 mm CL for males). Mean size and age (95% confidence limits) at sex transition, calculated from growth parameters, were 7.07 mm carapace length and 1.05 years, respectively. The reproductive strategies of pandalid shrimps are discussed in terms of the type of sex transition.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.4
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• pp.219-227
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• 1970

The shrimp fishery for Penaeus japonicus on the Koje-Do coast commences in May and continues to October. The best catches are made twice a year, namely June and September. Modal carapace length for the female is $51\~55\;mm$ in May, $51\~60\;mm$ in June occupying about 80 percent of the total catch. There is conspicuous mode in July and $46\~50\;mm$ in August. Modal carapace length for the male is $41\~45\;mm$ in May, $46\~50\;mm$ in June, $41\~45\;mm$ in July and August. The stock of p. japonicus can be divided into two groups, namely, spring and fall groups. Among samples of p. japonicus during the period from May through August the sex ratio consisted of about 33 percent females and 67 percent males, showing wide departure from a 1:1 ratio. The relationships between carapace length ($\iota$), body length (L) and body weight (W) are expressed by the following formulae : $$L=2.9418{\iota}+2.0166$$, $$W:1.449{\iota}^{2.2858}$$ (Mayssample) $$L=2.5551{\iota}+4.2986$$, $$W=1.528{\iota}^{2.2595}$$ (June sample) $$L=2.6738{\iota}+3.4037$$, $$W=1.341{\iota}^{2.3598}$$ (July sample) The relatlonship between carapace length ($\iota$) and ovary weight (W) is shown as follows: $W=2.695\times10^{-3}\iota^{4.2973}$ for May, June and July Samples.

• Animal Systematics, Evolution and Diversity
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• no.nspc2
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• pp.233-241
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• 1988

The crab, Macrophthalmus (Mareotis ) japonicus , collected in 1983 from CHojijin tidal flat, southeastern part of Kangwha Island , Korea, was studied. Its caraace breadth, the carapace length , and body height were checked , and the measured raw data were analysed for the growth ratios by the mode subtraction method from the frequency distribution compared with the probability graphs. The growth rate of the crab rose more in summer than in fall and exceeded 10% during the same period on Chojijin tidal flat in Kangwha Island , Korea. Four size groups of the crab appeared in June, 1983 , but they were put together into only on emixed group by autumn. The rapid growth of the crab in summer in middle latitude comes from the seasonal bio-rhythm and the best conditions for food. But the physiological activities of the crab are reduced from autumn and the growth rate reaches the upper limits in many individuals on this tidal flat. The more the crabs grow, the more the breadth ratios to the carapac length become larger and the slopes of correlation curve get smaller. The measured values from the carapace breadth of the crab are more useful for morphological studies than those values from the carapace length or body height.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.2
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• pp.110-116
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• 1970

The fresh_water shrimp, Palaemon modestua is one of the most important types of bait f[r fishing and can be found abundantly in the Nak-Dong River. The larval development of Palaemon modestua in the laboratory was reported by Liu (1949), Kown and Uno (1968), but they didn't give any ecological features in the natural environments. Shrimps were collected from the Nak-Dong River near Pusan, once a month from July to December 1953 and from February to June 1969 respectively. The following is a summary of the results: 1. They breed from April to September, mainly in July. 2. A generation of this type of shrimps appears to be approximately one year and after breeding they die off up untill the end of October. 3. The sex ratio (female=100) is $44.2\~95.5$ (mean 78.5) and goes down during spawning seasons. 4. The minimum size of the ovigerous female is approximately 0.5 gram in body weight, 29mm in body length and 7mm in carapace length. 5. Most shrimps of $31\~41mm$ In body length lay eggs. 6. The relationship between the boby length (X) and the number of eggs (Y) is: $$Y=0.0000203937X^{3.5668}$$ 7. The relationship between the body length (X) and the body weight (Y) is: $$Y=0.099801X^{2.85407}$$ in female. $$Y=0.004198X^{3.40614}$$ in Male. 8. The relationship between the carapace length (X) and the body weight (Y) is: $$Y=5.56008X^{2.25503}$$ in female. $$Y=5.09541X^{2.28875}$$ in male. 9. The relationship between the carapace length (X) and the body length (Y) is: Y= 5.07540+3.36057X in female. Y=4.90514+3.47791X in male.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.2
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• pp.422-435
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• 2017

Intermolt periods, growth rates, survival (%) and relative growth of the megalopa larvae of Portunus trituberculatus (Miers, 1876) were studied up to the crab 7th stage for 160 days in the 3 different temperature groups in which each has 60 larvae. The higher the water temperature was the shorter the intermolt period was in each crab stage. In addition, a deviation of intermolt periods was shown as few as the water temperature gets higher. The intermolt period in the 7th crab stage was $29.8{\pm}3.26$ days in the experimental group at the room temperature, $45.2{\pm}3.89$ days at the temperature of $17^{\circ}C$, and $25.6{\pm}2.23$ days at the temperature of $27^{\circ}C$, respectively. The survival (%) of larvae of P. trituberculatus (the crab 7th stage) is the highest in the group at the room temperature: However, they showed 15% at the temperature of $27^{\circ}C$ and 10% at the temperature of $17^{\circ}C$. All the groups were shown the similar relative growth, but significant differences appeared in some comparison. The sizes (mean growth of carapace width) of the crabs in the group at the temperature of $27^{\circ}C$ reached 5.01~25.45 mm length (it is the longest among the groups) from the crab 1th to the crab 7th stage. However, the sizes (mean growth of carapace width) of room temperature were 4.99~22.26 mm and the size of crab in the group at the temperature of $17^{\circ}C$ reached 4.8~17.26 mm, The sizes (mean growth of carapace length) of the crabs in the group at temperature of $27^{\circ}C$ reached 2.88~13.56 mm, However, the size of the crab in the group at the room temperature showed 2.88~12.34 mm, while in the group at temperature of $17^{\circ}C$, their average growth of carapace length were 2.51~8.03 mm. The growth rates of larvae of P. trituberculatus (from the crab 1th to the crab 7th stage) were changed with the increase of the instar stage, however their changes showed irregular.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.3
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• pp.396-404
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• 2015

Morotoge shrimp Pandalopsis japonica is caught by pot and others in the eastern coastal waters of Korea. Comparative fishing experiments were carried out in the eastern coast of Korea, using the dome-shaped pots with different five mesh sizes (17.1, 24.8, 35.3, 39.8, and 48.3 mm) in order to estimate the mesh selectivity of the pot for the morotoge shrimp, Pandalopsis japonica. The SELECT (Share Each Length's Catch Total) analysis method was applied to the catch data. The master selection curve of the pot for the shrimp was estimated to be s(R) = exp(15.770R-10.573)/[1+exp(15.770R-10.753)], where R is the ratio of carapace length to mesh size. From the selection curves, the carapace lengths of 50% retention were 11.6, 17.0, 23.9, and 34.1 mm for 17, 25, 35, and 50 mm mesh-size pot, respectively. It means that the pots of larger mesh size allow more shrimp of small size to escape.