• The Journal of Fisheries Business Administration
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• v.50 no.2
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• pp.41-56
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• 2019

The aim of this study is to analyze the productivity change of pollock enterprise by applying a mutually quadratic hyperbolic model and a bootstrapping model. This study used 20 units of pollock firms data (from 2013 to 2017). As a result of total productivity analysis of twenty pollock enterprises, total factor productivity was estimated to have decreased by 24.9% over the last five years (2013~2017). The main cause of this productivity decline was analyzed by technical change. In terms of annual productivity change, it showed decrease 3.0% in 2013~2014, 7.8% in 2014~2015, 4.5% in 2015~2016 and 4.7% in 2016~2017 respectively. In the analysis of productivity by corporation type, total factor productivity showed a significant decrease in both general corporation and external corporation, and productivity decrease (-29.3%) was larger than general corporation (-23.0%). In the productivity analysis by type of business, total factor productivity decreased significantly in the order of wholesale and commodity brokerage (-26.3%), food manufacturing (-25.1%) and fisheries (-15.3%). This decrease in productivity was caused by the technological change which indicates a downward shift in the production curve that is significant in all sectors.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.3
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• pp.207-214
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• 2012

This study was conducted to optimize the processing conditions, including the ingredient ratio and extraction time, for a water-soluble fraction of Alaska pollock head and non-forming sea tangle by response surface methodology. Our results indicated that the optimal independent variables for obtaining extracts with a high yield and desirable sensory characteristics were 1.32 for $X_1$ (extraction time), 1.36 for $X_2$ (sea tangle concentration) and 0.93 for $X_3$ (water volume) in coded values, and 5.48 h for $X_1$, 18.18% for $X_2$ and 6.86 times for $X_3$ in uncoded values. The predicted values of $Y_1$ (yield), $Y_2$ (TCA soluble-N) and $Y_3$ (overall acceptance) for extracts produced under these optimized conditions were 22.10%, 1.83 g/100 mL and 5.9, respectively, their experimental values were 21.4%, 1.7 g/100 mL and 5.7, respectively. No significant differences between the actual and predicted values were found.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.3
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• pp.179-187
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• 2010

This study examined ways to improve the functional properties of commercial soy sauce using gelatin hydrolysates from the refiner discharge of Alaska pollock, Theragra chalcogramma. The total nitrogen content and pH of gelatin sauce prepared by dissolving the second-step gelatin hydrolysates (15 g), salt (20 g), sugar (5 g), glucose (2.5 g), inosine monophosphate (IMP) (0.5 g), black pepper (0.1 g), caramel powder (0.1 g), ginger powder (0.05 g), garlic powder (0.05 g), vinegar (3 mL), and fructose (3 mL) in water(100 mL) were 1.71% and 5.35, respectively. The results of a sensory evaluation indicated that when preparing blended soy sauce, the optimal blending ratio of gelatin sauce to commercial soy sauce was 20:80 (v/v). Because the total nitrogen content and pH of the blended soy sauce were 1.52% and 5.31, respectively, the blended soy sauce could be sold as a soy sauce. The oxidative property of the blended soy sauce was similar to that of 20 mM ascorbic acid, and its angiotensin-converting enzyme (ACE) -inhibiting activity was 1.5 mg/mL. The results suggest that the antioxidative and ACE-inhibiting activities of commercial soy sauce can be improved by blending gelatin sauce (20) with commercial soy sauce (80). The total amino acid content of the blended soy sauce was 9,107.3 mg/mL, which was higher than that (8,992.4 mg/100 mL) of commercial soy sauce. However, the taste value of the blended soy sauce was 415.8, which was lower than that (431.2) of commercial soy sauce.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.3
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• pp.456-463
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• 2020

The diet of the walleye pollock Gadus chalcogrammus, was studied by examining the stomach contents of 864 individuals. Using gill nets, samples were collected monthly from January to December 2017 in Jugwang, Sokcho, Yangyang, Uljin, Ganggu, and Gampo, Korea. The specimens ranged in total length (TL) from 16.6 to 75.2 cm. G. chalcogrammus fed mainly on Euphausia pacifica (Euphausiacea) and less on Cephalopoda, Pisces, Mysidacea, and Macrura. The results indicated that G. chalcogrammus is a specialist feeder, feeding mainly Euphausiacea. With growth, however, its diet shifted from Euphausiacea to Cephalopoda, Macrura and Pisces. Smaller individuals (<40.0 cm TL) consumed mainly Euphausiacea. The proportion of Euphausiacea decreased with increasing body size, whereas the consumption of Cephalopoda and Macrura increased gradually.

• Journal of Life Science
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• v.26 no.8
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• pp.955-962
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• 2016

Fish-meat gel is an intermediate product used in a variety of surimi-based seafood. One of the most-used raw materials of fish-meat gel is Alaska Pollock due to its high-quality meat in terms of gel strength and texture. However, increasing demand for fish-meat gel, along with overexploitation of the wild catch Alaska Pollock, has put the industry in need of low-cost sustainable alternative sources for fish-meat gel. Pagrus major (PM) is a widely aquacultured fish known for having white meat that is low in fat. The current study compares the quality of fish-meat gel prepared from aquacultured PM to that of high and mid-grade Alaska Pollock fish-meat gel. Gels were compared in terms of gel strength, texture, color, and protein pattern. Results indicated that fish-meat gels prepared from PM were superior to Alaska Pollock fish-meat gels with regard to gel strength, hardness, springiness, chewiness, cutting strength, and breaking force. In addition, although not matching in quality, PM exhibited a cohesiveness, whiteness, and expressible moisture content comparable to Alaska Pollock of both grades. Protein pattern analysis also showed that PM and Alaska Pollock fish-meat gels had similar protein profiles before and after gel preparation. Therefore, P. major is suggested as a potential substitute for Alaska Pollock in fish-meat gel production.

• Journal of fish pathology
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• v.31 no.1
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• pp.9-13
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• 2018

We previously monitored nervous necrosis virus (NNV) in brain samples of artificially produced walleye Pollock (Gadus chalcogrammus) seedlings, with a low prevalence (1.8%, 1/55) but no clinical symptoms. Given that this virus is considered one of the most serious viral threats for almost all marine aquaculture fish species and characterized by both vertical and horizontal transmission, it would be interesting to monitor NNV in the fertilized eggs as well. We collected fertilized walleye pollock eggs from the farms located in Goseong during January to March, 2017. Approximately 50 mg of eggs were periodically taken from 4 each different batches, and 37 different pooled sample sets in total were made during sampling period. RNA was extracted from the eggs by using Trizol and cDNA was synthesized for RT-PCR for detecting NNV. Primers and PCR conditions are the same as previously described. As a result, NNV was not detected from any of the sample sets by one step PCR (0%, 0/37), suggesting NNV may not be a threat in walleye pollock aquaculture in Korea at present time. However, continuous monitoring for NNV should be conducted because introducing a new species into aquaculture industry involves potentials of disease outbreak and NNV is already known to cause outbreaks in gadoid fishes.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.4
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• pp.584-590
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• 2009

The effects of different washing time and pH adjustment of surimi-like materials from pork leg on quality characteristics were investigated. Surimi was made from pork leg by washing two or four times with water, as well as by pH adjustments of 3.0 or 11.0. The control surimi was made by two times washing from Alaska pollock. The content of crude protein was higher in the surimi manufactured from pork leg with pH adjustments. The highest gel strength was found in the control, and the control had greater lightness and whiteness value. The control had higher texture attributes than the other samples, whereas the surimi from pork leg made by a pH 11.0 adjustment had higher texture attributes than the pH 3.0 adjustment. The sensory color was higher in the control compared to other surimi samples, whereas aroma was lower in the control. However, there were no significant differences in overall acceptability among the surimi samples.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.4
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• pp.339-346
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• 2015

We examined the effect of warm temperature on the survival of larvae of walleye pollock and on their swimming behavior during the four days of post-hatch. Observations were conducted on larvae in Petri dishes and in 85 cm tall, cylindrical tanks that had a warmer upper layer and cooler lower layer separated by a small thermocline. Mortality was carried out in four temperature ranges from $3.1^{\circ}C$ to $9.7^{\circ}C$. The number of days to 50 % mortality ($D_{50}$) was longest (18.7 days) at $3.1^{\circ}C$ and decreased with increasing temperature to 10.3 days at $9.7^{\circ}C$. And $D_{50}$ were similar level to that at temperature 3.1 and $5.1^{\circ}C$(17.9 days). Larval responses to warmer temperatures varied depending on developmental stages. 2dph larvae changed the distribution to the thermocline of the water column. And, 3dph larvae had a ability for escaping from the unfavourable warmer temperature. These results suggest that the warmer water negatively affects the larval survival.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.1
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• pp.18-24
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• 2011

This study investigated the physicochemical and enzymatic properties of unmarketable cultured bastard halibut (Paralichthys olivaceus) of different weights as a potential source of surimi and surimi gel. The proximate composition of cultured bastard halibut of different weights did not differ significantly at P<0.05 (light weight (LBH) 400~500 g, medium weight (MBH) 600~800 g, and heavy weight (HBH) > 1,000 g). Compared to Alaska pollock muscle, the bastard halibut muscle had a 4% higher crude protein content and 6% lower moisture content. The collagen content of LBH bastard halibut muscle was 1.58 g/100 g, which was lower than or no different from bastard halibut weighing different amounts. Regardless of fish weight or pH, the enzymatic activities of crude fish extracts ranged from 0.34~0.48 U/mg for casein and hemoglobin, 11.0~12.7 U/mg for LeuPNA, 5.4~6.1 U/mg for ArgPNA, 2.3~2.9 U/mg for SAAPFNA, and 0.1~0.2 U/mg for BAPNA. The yield of surimi gel from LBH was 24.4%, which was similar to that from MBH and lower than that from HBH. The surimi gel from LBH was similar to that from HBH, while weaker than that from MBH. The surimi gel from LBH gel was stronger than grade SA gel from commercial Alaska pollock.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.598-605
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• 2010

This study investigated the physicochemical and enzymatic properties of unmarketable bastard halibut (Paralichthys olivaceus) cultured in different regions (i.e., Jeju, Wando, and Geoje) as a potential source of surimi and surimi gel. The proximate composition of unmarketable bastard halibut cultured in different regions did not differ significantly at P<0.05. Compared to Alaska pollock muscle, all of the unmarketable bastard halibut muscle had a 4% higher crude protein content and 5% lower moisture content. The collagen content of bastard halibut muscle cultured in Jeju was 1.96 g/100 g, which was higher than in fish cultured in other regions. Regardless of the region where cultured or pH, the enzymatic activities of the crude extracts from unmarketable bastard halibut muscle ranged from 0.30.0.48 U/mg for casein and hemoglobin, 11.9.13.7 U/mg for LeuPNA, 5.6.6.7 U/mg for ArgPNA, 2.8.4.7 U/mg for SAAPFNA, and 0.1.0.2 U/mg for BAPNA. Regardless of region, no mercury or lead was found in any of the unmarketable bastard halibut muscle, except for lead in fish cultured in Geoje. The strength of surimi gels from unmarketable bastard halibut cultured in Jeju, Geoje, and Wando was 1059, 988, and 900 g${\times}$cm, respectively. The surimi gel from unmarketable bastard halibut cultured in Jeju was stronger than commercial Alaska pollock surimi, which was grade SA.