• Journal of the Korean Dietetic Association
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• v.20 no.4
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• pp.306-319
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• 2014

This study is basic research focused on product development and market activation based on analysis of current usage and demand for development of processed blue crabs. A total of 556 subjects aged 20s to 60s living in the Seoul area were surveyed. According to the survey, 65.1% of subjects consumed blue crabs at home, and 82% of them purchased blue crabs whole and undressed. Respondents gave higher marks to taste, nutrition, and texture compared to ingredient preparation, eating method, and price. Majority of blue crab consumers had no experiences of consuming processed blue crabs. Exactly 57.0% of consumers purchased them at big shopping centers, and the reason for purchasing was their good taste. When female consumers purchased processed blue crabs, they checked every part carefully compared to male consumers. Women gave high scores to blue crab powder, blue crab extract, blue crab croquette, and blue crab cake compared to men, demonstrating the necessity of developing processed blue crabs. Furthermore, the experienced processed blue crab group recognized the necessity of developing processed blue crabs compared to the inexperienced group. People showed significant differences in purchasing processed blue crabs according to gender as well as previous experience of blue crab consumption.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.6
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• pp.708-719
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• 1995

This study is to estimate abundance of the Chesapeake Bay blue crab stock. Using 823 dredge tows which were conducted during the 1991 winter survey, blue crab abundance was estimated on the basis of newly developed methods which account for unequal dredge tow distances, size- and sex-specific heterogeneous overwintering spatial distributions, wintertime exploitation, the time period of quasi-hibernation, and dredge capture efficiency. The estimate of total abundance before correction by gear efficiency was 131.8 million crabs $(95\%\;C.I.\;=\;118.2\;million\;crabs\;to\;145.4\;million\;crabs),$ Dredge capture efficiency was estimated to be 0.474. Thus, the estimate of total abundance was calculated as 278.1 million crabs after correction by the efficiency factor.

• Journal of the korean society of oceanography
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• v.37 no.4
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• pp.232-241
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• 2002

The potential role of environmental factors on extractable lipofuscin accumulation rate in the blue crab was studied by examining the effect of temperature on laboratory reared blue crabs and the effect of trace metals from samples collected at impacted sites (Baltimore Harbor) and a relatively pristine site (outdoor ponds at Horn Point Laboratory, Cambridge, MD, USA). Lipofuscin levels did not significantly related with sampling sites or heavy metal concentrations in the crab tissue. Heavy metal body burden was highly variable among sampling sites and tissue types but significantly higher for both impacted areas (Curtis Creek and Inner Harbor) in comparison to the reference site. Among tissue types, gills showed the highest metal concentrations with the exception of Hg, which was highest in muscle tissue. For two groups of crabs that were held at either ambient (4 to 1$0^{\circ}C$) or heated seawater (19$^{\circ}C$) for two months, normalized-lipofuscin levels were significantly different (P-0.001). Results suggest that temperature may affect lipofuscin accumulation (=0.25ng-lipofuscin/mg-protein/temperature-degree day). Therefore, temperature should be considered for accurate age calibration of crab populations using lipofuscin.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.4
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• pp.369-379
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• 1993

Using a successive removal approach the mechanism of sampling capture efficiency of blue crabs by dredges was studied in Chesapeake Bay during winter 1992. For the twenty-six field experiments no significant statistical differences were detected in dredge efficiency using general linear model analysis by factors including bottom sediments, water depths, and sampling vessels. Dredge efficiency (i.e., catchability) was estimated by two methods, Leslie (Leslie and Davis, 1939) and a simple revised method. Mean catchability was estimated at 0.26 (SE=0.03), indicating that only $26\%$($95\%\;C. I.=20{\sim}32\%$) of crabs present in the path of the dredge of a given sampling area are caught with a single dredge tow. Dredge efficiency declined exponentially as crab density increased.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.1
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• pp.48-55
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• 2009

The gonad maturation and spawning of blue crab, Portunus trituberculatus (Miers, 1876) using samples caught by trammer net in the western coast of Korea from January to December. The gonadosomatic index (GSI) showed the highest value of 15.0 in June and lowest value of 1.29 in August. Hepatosomatic index (HSI) showed the lowest in the spawning season from June to July. Thereafter, from August the value started to increase to 5.77 in December, showing an adverse trend against GSI. In the histological studies of the female reproductive organ, the gonad filled with primary oocytes from January to February and secondary oocytes in May. The female gonads mature from June, and mature and immature groups could be distinguished from December to February or March. In August, female developed another cycle of gonad development, showing new primary oocytes in the gonads again. Some of female crabs had receptaculum filled with already active sperm cells in it from March to May. In the time of August to September, almost all the females had the sperm sacs in the receptaculum. From the result, the coupling period estimated from August to September. Total RNA and DNA values of the crabs were highest in May (2.51, $0.57{\mu}g/mg$). The DNA value remained unchanged except for the value in May ($0.09-0.13{\mu}g/mg$). while RNA value was lowest in January ($1.08{\mu}g/mg$). The RAN/DNA ratio was the lowest (6.23%) in May and highest (18.05%) in July. The value of correlations coefficient between body weight and fecundity of the crabs was higher that of between carapace width and fecundity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.6
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• pp.581-585
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• 1985

This study was carried out with blue mussels at Otsuchi Bay in Japan from August 1981 to May 1982, in order to investigate the effect of the parasitic pea crab (Pinnotheres pholadis) on the reproductive capacity of host blue mussels (Mytilus edulis galloprovincialis). The results show that pea crabs delay gonad development of host mussels about one month and lower their fatness rate by intercepting nutrients. The parasitization with pea crabs is thought not to prevent spawning activity itself, but to reduce the number of germ cell resulting in the reduced space of gonads.

• Korean journal of food and cookery science
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• v.12 no.4
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• pp.469-480
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• 1996

Nitrogenous constituents in the extract of 3 species of raw and boiled crabs, tenner crab (Chionoeretes opilio elongatus), horsehair crab (Erimacrus isenbecki), and blue crab (Portunus trituberculatus) caught in the Korean adjacent sea, were analyzed and compared their compositions with the sex and the tissues, body meat, leg meat, and viscera. The crabs contained about 3％ of the extractive nitrogenous constituents in the tissues, meat and viscera. The free amino acid compositions were commonly featured a high content of arginine, taurine, proline, and glycine regardless of the differences in species and tissues. Free amino acids and quarternary bases were greatly increased in hot water extraction while nucleotides were slightly diminished. Glycine betaine and trimethylaminoxide were accounted for above 30% of the total extractive nitrogenous constituents. Arginine, taurine, proline, glycine, glycine betaine, and trimethylaminoxide which abundant in the meats and viscera of the crabs were estimated to greatly contribute directly or indirectly toward appearing the characteristic crabs taste.

• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.296-302
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• 2019

Ganjang-gejang (soy sauce-marinated crab) is a ready-to-eat (RTE) seafood and is also one of the most popular traditional dishes in Korea. It is generally prepared by washing raw blue crabs and then preserving them in soy sauce. Since this process does not involve cooking or any treatment with heat, it is difficult to control the microbiological quality of the final product. Thus, the objectives of this study were to compare the efficacies of various sanitizers in eliminating microorganisms on raw blue crab during the washing step and to evaluate the effectiveness of chitosan on the inhibition of microbial growth in the ganjang-gejang during storage. The raw blue crabs were submerged in chlorinated water (50 mg/L), peracetic acid (40 mg/L), acetic acid (5%) and lactic acid (5%) for 10 min at $25^{\circ}C$, respectively. The blue crabs treated with 5% acetic acid were marinated with soy sauce containing 0.5 and 1% of soluble chitosan, followed by storing them at 4 and $12^{\circ}C$ for up to 30 days. Results show that 5% acetic acid reduced the microbial populations on the blue crabs by 1.5 log CFU/g, which was significantly higher than those of other treatments. Based on these results, 5% acetic acid was selected for the washing step. The microbial populations of all ganjang-gejang samples significantly increased to about 8.0 CFU/g at $12^{\circ}C$ for 7 days. At $4^{\circ}C$, the microbial populations of the products containing 1% chitosan increased by about 2.9 CFU/g for 20 days, which were significantly lower than those (4.2-4.5 log CFU/g) of the products without and with 0.5% chitosan. Thus, these results suggest that 5% acetic acid washing of raw blue crabs and the addition of 1% chitosan in ganjang-gejang could improve the microbiological quality of the final products under refrigerated condition.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.714-719
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• 2001

An interest in traditional foods is growing in an effort to preserve dietary culture in Korea. Blue crab preserved in soy sauce, one of the Korean traditional foods is especially popular in summer and is produced in the Jeollanam-do province, Korea. However, there has been no report on processing of the blue crab. The objective of this research is to investigate changes of nutritional composition in blue crab preserved in soy sauce. Moisture content was a little higher in FBC (Fresh Blue Crab) than in PBC (Preserved Blue Crab) and ash content was greatly higher in PBC than in FBC. Salt content was 1.50% in FBC and 7.89% in PBC. The amount of free sugars in FBC was very low but was increased after preserved using soy sauce, especially of fructose significantly. After preserved, the pH of blue crab was also increased. The contents of most total amino acids in blue crab were decreased after preserved, but free amino acids were increased. Major total amino acids were glutamic acid, arginine and aspartic acid in two samples and major free amino acids were arginine, proline and alanine. Fatty acid content was decreased after preserved and major fatty acids were palmitic acid (16 : 0), oleic acid (18 : l), eicosapentaenoic acid (20 : 5) and docosahexaenoic acid (22 : 6).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.3
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• pp.174-183
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• 2008

In order to develop the substitutive materials for natural baits of swimming crab pots, the fluorescent characteristics of the baits were analyzed, and the preference of fluorescent dyes were investigated by the mean entrapped catch number to the pots through the water tank experiments and fishing experiments. On the investigation of fluorescent characteristics by the 5 kinds of baits, mackerel, krill, manila clam, pig's fat and chicken's head which were used in substitutive baits for test in the UV long wave(365nm) area, it showed clear blue fluorescence in the skin of mackerel, shell of krill, manila clam and bill of chicken's head, and green fluorescence in the mackerel s muscle and internals, and yellow fluorescence in the pig's fat and chicken's head. On the investigation of fluorescent characteristics by the bait cages in the UV short wave(254nm) and long wave(365nm) area, it showed each green, red and blue fluorescence in the cylinderical or hexahedral red plastic bait cages which were painted each green, red and blue fluorescence dyes, but it showed yellowish green flourescence in the cylinderical or hexahedral red plastic bait cage which was painted yellow fluorescent dye. On the preference investigation of the fluorescent dyes of swimming crabs by the 5 kinds of the bait cages which were put the mackerel in the non-fluorescent red plastic cage($RF_N$), red, yellow, green and blue fluorescent plastic cages(RF, YF, GF, BF) each, nonfluorescent red plastic cage($RF_N$) was entrapped mean 2.0(6.7%), but blue fluorescent plastic cage(BF) was mean 5.0(16.7%) and it was more 2.5 times comparing to $RF_N$, and red fluorescent cage(RF) was same level and green fluorescent cage(GF) was 50% of catch number comparing to $RF_N$, and yellow fluorescent cage(YF) was entrapped nothing(F 46.324, P < 0.05). On the investigation of the entrapped catch number to the pots which were put the mackerel in the blue fluorescent hexahedral plastic cage(HP) and blue fluorescent silicon mackerel model cage(SM), HP was mean 3.4(11.3%) and it was a little more comparing to SM which was entrapped mean 3.2(10.7%)(t 0.775, P > 0.05). Fishing experiments on the preference investigation of swimming crabs by the pots which were put in the non-fluorescent red plastic cage($RF_N$) and blue fluorescent plastic cage(BF) were conducted 3 times. Mean catching number and weight of $RF_N$ were 71.7 ind.(18.3%) and 16.9kg(64.3%), and those of BF were 93.0 ind.(23.1%) and 19.8kg(64.5%), respectively.