• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.5
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• pp.346-352
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• 2008

Yellow croaker (Larimichthys polyactis) is a major target species of large pair trawl fishery in the East China Sea. To standardize catch per unit effort (CPUE) of yellow croaker for the large pair trawl fishery, generalized linear model (GLM) was applied to evaluate and eliminate the influence of the explanatory factors (year, month, horse power and gross tonnage of vessel) on daily catches per boat collected and compiled by National Fisheries Research and Development Institute (NFRDI) from 1990 to 2007 at the fishery auction places of Busan, Masan and Incheon in Korea. Results of GLM showed that all of the factors significantly influenced on CPUE, explaining 36% of the total deviance. The standardized CPUE indicated that the abundance of yellow croaker in 2000's was 1.7 times higher than the CPUE in 1990's.

• Fisheries and Aquatic Sciences
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• v.24 no.2
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• pp.63-77
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• 2021

The aim of this research was to investigate different factors, including cryoprotective agents (CPAs), diluents, dilution ratios, equilibrium times, freezing rates, and thawing methods to optimize cryopreservation protocols for large yellow croaker (Larimichthys crocea). The parameters evaluated were sperm motility, sperm activity index (SAI), survival rate, and DNA damage. Different types of CPAs, such as dimethyl sulfoxide (DMSO), propylene glycol (PG), ethylene glycol (EG), methanol, and glycerol, were tested for sperm preservation. The highest motility, SAI, and survival rate were observed when EG was used. Different diluents such as Stein's solution, Hank's balanced salt solution, marine fish Ringer's solution, artificial seminal plasma (ASP) of small yellow croaker, and Cortland solution were investigated. The highest post-thaw motility was observed upon using ASP as the diluent. Different concentrations of EG were then mixed with ASP to identify the optimal EG concentration. Experimental results showed that the motility (70.33 ± 1.20%), SAI (5), and survival rate (78.30 ± 0.42%) of post-thaw sperm were optimum when 10% EG and ASP were used as the CPA and diluent of cryopreservation, respectively. Post-thaw sperm motility was high at equilibration times below 150 s and at an optimum dilution ratio of 1:1 (sperm: CPA + diluent) and was not significantly different compared with fresh sperm motility. The freezing rate was found to be slow below -10℃/min. The thawing temperature of 45℃ was identified as ideal. The percentage of tail DNA in post-thaw sperm at 10% EG and ASP was also investigated and was found to have more significant DNA damage than that in fresh sperm but significantly lower damage than that in post-thaw sperm at EG concentrations of 5%, 15%, and 20% (p < 0.05). The cryopreservation protocols obtained in this study will be useful in large yellow croaker hatcheries.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.3
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• pp.368-377
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• 2014

Small yellow croaker is one of the important stocks in Korean waters. In this study, we conducted sea trials to estimate optimum height of a drift gill net for effective fishing of small yellow croaker. In the trial using existing net which has 9.2m in height, there was 22 species (1,180 fishes, 99.9kg) caught. The catch (in individuals) of small yellow croaker, especially larger fishes (over 22cm in FL), was higher as part of net height is higher, while the number of species bycaught and the catch of those species were higher as part of net height is lower. In the trial using extension net which has 18.4m in height, there was 27 species (2,030 fishes, 151.7kg). It showed same pattern with existing net in the section I to III, however, in the section IV which is over 13.8m of net height, the catch sharply decreased. The number of species bycaught and the catch of those species using extension net were also same as results using existing net. It showed that section III (9.2-13.8m) where is upper-middle part of the net has caught most of catch and large fishes having over 22cm in length. Through these results, it is judged that the setting depth of the net where is 4.6-13.8m above the sea bottom is the best to reduce bycatch and catch much more large size fishes, and the catch per net is proportional to filtering area of net. Therefore the Fisheries Resource Management Act (the clause 1, article 10) on the amount of usage for offshore drift gill net need to be considered not only length of a net but also net height.

• Fisheries and Aquatic Sciences
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• v.26 no.10
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• pp.628-636
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• 2023

Stomach contents of three commercially important species, anchovy (Engraulis japonica), small yellow croaker (Larimichthys polyactis) and yellow goosefish (Lophius litulon) were analyzed to investigate difference of prey between Spring and Fall. Trawl surveys for target fishes were conducted at 12 stations by the RV Tamgu-8 in the Yellow Sea-Korean side in Spring and Fall 2008 as a part of the United Nations Development Programme/Global Environment Facility (UNDP/GEF), Yellow Sea Large Marine Ecosystem (YSLME) survey. Stomach contents of 50 individuals of each species were analyzed to species level of prey, if the number of specimens was more than 50 for each species. Fullness and digestion condition of stomach contents were determined by five and six levels, respectively. In anchovy stomachs, 23 species in Spring and 15 species in Fall were identified, respectively. Stomach contents were mostly occupied by copepods and euphausiids, mostly Euphausia spp., calyptopis in Spring while by copepods and amphipods in Fall. In small yellow croaker stomachs, 23 species in Spring and 11 species in Fall were identified. Stomach contents were mostly occupied by copepods and euphausiids in Spring, but by only euphausiids in Fall. Total 368 yellow goosefish (151 in Spring and 217 in Fall) were captured, but stomach contents only in Fall were analyzed. Most of stomach contents were anchovy with small proportion of Hakodate sand shrimp, Tanaka's snailfish, Pacific cod, and miscellaneous things. The present research unveiled that main food items of plankton feeder were distinctly different by species and seasons in the Yellow Sea-Korean side, as coincided with previous reports.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.3
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• pp.315-323
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• 2023

The maturity and spawning of the large yellow croaker Larmichthys crocea were investigated using samples randomly collected in the Jeju coastal area, Korea. We analyzed monthly changes in maturity stages, gonadosomatic index (GSI), and egg diameter. Additionally, we verified fecundity by size class and total length (TL) at sexual group maturity at 50%, 75%, and 97.5%, as well as by sex ratio (female vs. male). The overall sex ratio of females to males was 1:0.42. The GSI values showed a peak in October, but the spawning season, revealed by the microscopic analysis of gonadal tissue of L. crocea was from October 2021 to March 2022, with the main spawning period from October to November. The fecundity (F) of female L. crocea ranged from 39,232 eggs at 20 to 29.9 cm to 251,003 eggs at 50 to 59.9 cm, with the relationship between TL and F being 80.244TL-1641.6. In females, TL at 50%, 75%, and 97.5% maturity was 22.4, 24.3, and 29.0 cm, respectively.

• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.803-811
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• 2003

This study compared the physicochemical characteristics of yellow pigments in domestic and imported yellow croakers during distribution and storage. The croaker is generally adulterated by mixed color product of red and yellow pigment. This study found that the yellow pigment was stable during pH and temperature changes, but the red pigment was less stable than the yellow pigment. As for the light effect on the yellow pigment and the red pigment, there was no change in the remaining rate of the pigment stored in a dark place. The moisture content decreased according to the storage period, and the width of changes was large in the order of croaker stored at $5^{\circ}C$, croaker stored at $15^{\circ}C$ and dried croakers. The yellowness value of the abdomen of the adulterated white croaker did not show any large difference at the initial stage and for a storage period of 10 days at $5^{\circ}C$. However, the yellow croakers showed a decreasing trend according to the storage period at $15^{\circ}C$. The croaker can be generally adulterated by a mixed color of red and yellow pigment. For the texture change in accordance with the storage condition of the croakers, both the yellow and white croakers showed a gradually increasing trend of hardness when stored at $5^{\circ}C$ and $15^{\circ}C$.

• Journal of Applied Biological Chemistry
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• v.58 no.4
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• pp.363-368
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• 2015

The pharmacokinetics of florfenicol were studied in healthy and vibriosis-infected large yellow croaker (Pseudosciaena crocea) following administration of a single oral dose of $20mg{\cdot}kg^{-1}$ at $25{\pm}2^{\circ}C$. After oral administration, florfenicol levels in tissues (liver, kidney, muscle, serum, and skin) were analyzed using high-performance liquid chromatography. A two-compartment open model was used to describe the pharmacokinetics of florfenicol following oral administration. Compared to the healthy group, the absorption rate of vibriosis-infected fish significantly decreased, peak-time ($T_{max}$) delayed, maximum concentration ($C_{max}$) declined, total body clearance decreased, the elimination half-life ($T_{1/2{\beta}}$) was extended, and the area under the curve increased. These results indicate that a $20mg{\cdot}kg^{-1}$ oral dose of florfenicol administered once daily continuously for 4 or 5 days can be used for the treatment of Vibrio alginolyticus infection in large yellow croaker (Pseudosciaena crocea).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.2
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• pp.224-233
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• 2016

The objective of this study was to develop an artificial neural network (ANN) model for the acoustic identification of commercially important fish species in Korea. A broadband echo acquisition and processing system operating over the frequency range of 85-225 kHz was used to collect and process species-specific, time-frequency feature images from six fish species: black rockfish Sebastes schlegeli, black scraper Thamnaconus modesutus [K], chub mackerel Scomber japonicus, goldeye rockfish Sebastes thompsoni, konoshiro gizzard shad Konosirus punctatus and large yellow croaker Larimichthys crocea. An ANN classifier was developed to identify fish species acoustically on the basis of only 100 dimension time-frequency features extracted by the principal components analysis (PCA). The overall mean identification rate for the six fish species was 88.5%, with individual identification rates of 76.6% for black rockfish, 82.8% for black scraper, 93.8% for chub mackerel, 90.6% for goldeye rockfish, 96.9% for konoshiro gizzard shad and 90.6% for large yellow croaker, respectively. These results demonstrate that individual live fish in well-controlled environments can be identified accurately by the proposed ANN model.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.3
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• pp.205-213
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• 2022

The experimental fish transplanted from China in 2015 was used after seedling production and cultivated. Breeding management for experiment was carried out from October 2020 to February 2021. Also, it succeeded in inducing artificial maturation three to four months earlier than wild broodstock and secured good quality fertilized eggs. The average size of fertilized eggs was 1.22 mm, at 20℃ Blastodisc (15 minutes post-fertilization), 2 cell (50 minutes), 4 cell (1 hours), 8 cell (2 hours), 16 cell (2 hours and 30 minutes), 32 cell (2 hours and 50 minutes), morula (3 hours), blastula (8 hours), gastrula (15 hours), skull formation (20 hours), organ formation (30 hours) and hatching yolk larvae stage (35 hours). The total length of the just hatched larvae were 2.50 ± 2 mm, and then gain growth of 42.5 mm by 60 days, reaching 45 ± 5 mm.

• Korean Journal of Ichthyology
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• v.36 no.2
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• pp.182-187
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• 2024

Feeding habits of the large yellow croaker, Larimichthys crocea, was studied using 816 specimens collected by large pair-trawl fishery from June 2021 to May 2022 in the coastal waters of Jeju Island, Korea. The range of total length was 19.8~57.4 cm. Using the IRI, Pisces were mainly prey component constituted 57.5%. Euphausiacea and Macrura were important prey component constituted 23.2% and 18.7%, respectively. There was a significant difference in the change in diet composition by size group. As the L. crocea grew, the feeding rate of Euphausiacea decreased and the feeding rate of Pisces increased. There were also significant differences in the changes in diet composition by seasonal group. The most important prey species for L. crocea in the winter and spring were Pisces, in the summer it was Macrura, and in the fall it was Euphausiacea. As a result of analyzing the feeding relationship between size groups and season groups, L. crocea showed significant differences in the interaction between size groups and season groups.