• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.6
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• pp.337-342
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• 2007

The formation of lysinoalanine (LAL) in protein recovered from the belanger's croaker, Johnius grypotus, using a pH shifting process was measured by amino acid analysis. The LAL peak was detected at 49.24 min, between phenylalanine and histidine peaks in the amino acid analyzer. LAL was not detected in the fish muscle or in protein recovered using the alkaline pH shifting process. LAL was not formed in protein recovered after storage for up to 9 hrs at pH 11, but was detected in the soluble protein fraction at pH 11, followed heating at $90\;^{\circ}C$. The myosin heavy chain decreased with storage time at pH 11. The results suggest that the alkaline shifting process for recovering fish muscle protein is safe, and that no LAL forms.

• Ocean and Polar Research
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• v.37 no.2
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• pp.161-177
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• 2015

This study analyzes the stock assessment of yellow croaker caught mainly by the Korean stow net and gill net fisheries focusing on single species and multiple fisheries. This study standardizes fishing efforts for the two fisheries using the general linear model and uses a surplus production model based on the exponential growth model. The Clarke Yoshimoto Pooley model estimates a maximum sustainable yield(MSY), an allowable biological catch(ABC), fishing efforts for MSY($E_{MSY}$) and for ABC($E_{ABC}$). The bio-economic model is used to estimate the maximum economic yield(MEY) and fishing efforts for MEY($E_{MSY}$). Also, the study employs an economic analysis to estimate the economic interaction between stow net and gill net fisheries. The economic analysis shows the profit accruing to the two fisheries from estimated ABC. Finally, the study compares TACs based on single species and single fishery to TAC based on single species and multiple fisheries. The study proposes that the TAC assessment is necessary for single species and multiple fisheries in order to preserve resources.

• Ocean and Polar Research
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• v.28 no.3
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• pp.287-290
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• 2006

Eye growth and lens diameter of brown croaker Miichthys miiuy were positively allometric between hatching and 180 days post-hatch (d.p.h.). Eye growth in relation to head length and head height was nearly isometric. Eyes were formed completely at 14 d.p.h. At this age, the eye has a crystalline lens, an optic nerve fiber layer, a ganglion cell layer, an inner plexiform layer, an inner nuclear layer, an outer plexiform layer, an outer nuclear layer, an outer limiting membrane, and a pigment epithelium. The essential demands that must be met by the retina in this species pertain to light sensitivity and spatial resolution.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.3
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• pp.232-248
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• 2004

In order to utilize fisheries resources under a joint management scheme with adjacent nations, as well as detecting of fishing grounds, the factors which influence yellow croaker (Pseudosciaena polyactis) in Korean waters were studied using historical catch per unit effort and oceanographic data. The main fishing ground near Cheju Island was located along the thermal front formed between the Yellow Sea Bottom Cold Water (YSBCW) and northward moving warm current. When the YSBCW (index temperature: $10^{\circ}C)$ strongly extended southward, the fishing condition were worse than average. Especially, low temperatures greatly influenced stow net fisheries, which were operated in the deep water layer The concentration and dispersal of fishing ground and catch coincided with oceanographic features and the seasonality of water masses.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.4
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• pp.352-359
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• 2012

For rebuilding and managing fish stocks and fisheries, the biological and socioeconomic evaluations on fisheries management regulations are important. This study aimed to estimate the economic effectiveness of different mesh sizes in the yellow croaker gillnet fishery. In particular, by comparing economic effects of mesh sizes, 50mm and 52mm, it aimed to provide the economic validity for increasing mesh sizes. Analytical results showed that the fishing revenue was higher in the vessels using a mesh size over 52mm than that in the vessels using a mesh size less than 50mm. In addition, the effect of fishing cost reduction was also larger in the vessels using a mesh size over 52mm than that in the vessels using a mesh size less than 50mm.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.4
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• pp.327-334
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• 2019

The feeding habits of the bighead croaker Collichthys niveatus were studied using 745 specimens collected by bottom trawl net in the West Sea, Korea, in April and October of 2016, 2017 and 2018. The size of C. niveatus ranged from 4.8 to 16.0 cm in total length. The stomach contents analysis indicated that C. niveatus consumed mainly euphausiids and copepods. C. niveatus consumed mainly euphausiids and copepods in all size classes. The dietary compositions of C. niveatus was not significantly different among size classes (One-way ANOVA, P > 0.05). As body size of C. niveatus increased, the mean weight of prey per stomach (mW/ST) tended to increase.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.2
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• pp.145-152
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• 2024

The present study investigated the digital color characteristics corresponding to different maturity stages and maturation levels of white croaker Pennahia argentatus specimens collected from the Southern Sea of South Korea. Maturity stages were determined using photomicrographs depicting ovarian developmental phases and compared with digital color values. The specimens ranged in body length from 21-36 cm, with mature ovaries observed within the 24-30 cm length range. To differentiate the maturing, mature, spawning, and post-spawning stages of the gonads, boundary lines were established based on specific coordinates. For the ovaries, a dividing line was drawn through (-10, -10) and (15, 5), described by the equation Y=3/5X-4; while for the testes, the line passed through (20, 0) and (0, 15), indicated by the equation Y=-3/4X+15. However, the visual determination of the maturity stages proved challenging due to overlapping color values. Consequently, this study underscores the efficacy of employing digital color measurements over subjective visual assessments to evaluate the maturity of white croaker gonads and offers more quantitative insights.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.37-44
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• 1992

Annual biomasses of small yellow croaker, Pseudosciaena polyactis, were estimated by biomass-based cohort analysis (Zhang, 1987) , using data on annual catch in weight at age for 1970-88 in Korean waters. Annual biomass of croaker was highest in 1974 with about 100,000 mt, declining to a level of 20,000-30,000 mt after 1981. Adult biomass also showed a peak in 1974 with about 50,000 mt. Afterwards, however, it continuously dropped. According to the estimates of biomass at age obtained from this analysis, the age composition of small yellow croaker in the 1980's differed greatly from that in the 1970's. The proportions of older croakers (>5 years) were very low in the 1980's and even the biomasses of young croakers (1-4 years) were at a very low level in the 1980's. Year classes of 1968, 1972 and 1978 appeared to be relatively dominant. The mean value of instantaneous fishing mortality (F) in the 1980's was twice that of the 1970's. Recruitment of croaker exhibited an unusally linear relationship with adult stock biomass.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.5
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• pp.423-429
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• 2001

Prediction of the variation in annual biomass was conducted for the white croaker. Argyrosomus argentatus in Korean waters using leslie Matrix, based upon fishery data for the past 21 years and biological data, We used density-independent and density-dependent Leslie Matrix models. Similar parameters were estimated from two models except that the density-dependent model was influenced by the density effect variable, q(i,t), The eigenvalue of the white croaker population for the $1984\~1995$ period was estimated to be 0.8, indicating a declining pattern of the population. The survival rate of 0-th year class was calculated to be 0.00005. Based on the schedule of the age-specific survival rate and fecundity, the future biomass and catch was predicted for various levels of fishing mortalities (F), If F was set at 0.252/yr ($F_{35x}$) or 0.368/yr ($F_{0.1}$), the biomass and catch increased, and if F was set at 0.922 ($F_{current}$), the biomass and catch decreased, The fishing mortality at equilibrium was estimated to be 0.7/yr. Finally, the management strategy of the white croaker was discussed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.3
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• pp.169-175
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• 2004

In order to examine the mesh selectivity and optimum mesh size of gill nets for croaker, Milichthys miiuy, the field experiments were carried out during Aug. 10 to 14, 2002 and Aug. 10 to 17, 2003 at the caostal area of Imja-Do, Shinan, Jeonnam province. The experimental fishing gears were used in two set of gill nets, which one set was consisted of 12 sheets of gill nets, and each set was connected alternatively 4 different sheets that were 129mm, 135mm, 144mm and 150mm in mesh size. The analysis of mesh selectivity curve was done by Kitahara's method. The results obtained are summerized as follows : 1. The total number of catch by the experimental fishing of gill nets for croaker was 719, and it was consisted of 526 croakers (73.1%), 168 blue crabs (23.4%), 17 harvest fishes (2.4%) and 8 other fishes (1.1%). 2. The value of maximum 1/m on the mesh selectivity curve was estimated at 6.91. 3. The value of 1/m on the 50% selection range was estimated at 5.62${\sim}$80.3, and the selection width was 2.41. 4. The optimum mesh size of gill nets for croaker was estimated 142mm, and the 50% selection range of total length of croaker was 798${\sim}$1,140mm.