• Animal cells and systems
• /
• v.11 no.2
• /
• pp.183-189
• /
• 2007

To investigate the properties of mucosubstances of the epidermis in various teleostean species, conventional histochemical stainings were used on the skin in five species of order Perciformes, i. e., yellowtail, Seriota quinqueradiat, striped beakperch, Oplegnathus fasciatus, brown spotted grouper, Epinephelus chlorostigma, sea chub, Ditrema temmincki and multicolorfin rainbowfish, Halichoeres poecilopterus. The following methods were used: periodic acid Schiff (PAS), alcian blue (AB) pH at 2.5, AB pH at 1.0, AB pH at 2.5-PAS, AB pH at 1.0-PAS, aldehyde fuchsin (AF) pH at 1.7-AB pH at 2.5 and high iron diamine (HID)-AB pH at 2.5. The epidermis of all five species consisted of three layers: superficial, middle, and basal layer. The superficial layer was comprised of rather flattened cells. In particular, the outermost layer of striped beakperch and middle layer of sea chub consisted of mucus-secreting cells. Mucous cells, the unicellular glands, were found in epidermis but varied in number in different body regions and species. Although there was a slight difference in the amount in various species and body regions, the secretory contents of the mucous cells in the five teleostean species contained acidic mucopolysaccharides. In yellowtail, striped beakperch, and multicolorfin rainbowfish, the property of mucosubstances was identified as sialomucin, while it was sulphomucin in brown spotted grouper and sea chub.

• Fisheries and Aquatic Sciences
• /
• v.14 no.4
• /
• pp.257-265
• /
• 2011

The effects of cooking method (grilling, frying, steaming, and microwaving) on the proximate composition and protein quality of chub mackerel Scomber japonicus treated with 2, 6, and 10% sodium chloride (NaCl) brine were investigated. Moisture content decreased in all cooked samples from 60.22% in the raw sample to 48.7% in the fried samples. Brine (10% NaCl) treatment recorded the highest moisture loss. All cooked samples showed a decrease in fat content, except fried samples. Protein content increased in all cooked samples, from 47.21% in the raw sample to 63.87% in the grilled sample. Brine treatment resulted in the highest degree of fat oxidation (thiobarbituric acid-reactive substances), which was highest in the fried samples and lowest in the microwaved samples. The trypsin inhibitor (TI) concentration was highest in the microwaved samples and lowest in the fried samples. In all samples, 6% salt treatment caused the lowest TI level and the highest in vitro protein digestibility. In vitro digestibility increased from 79.4% in the raw sample to 86.43% in the fried samples. The total essential amino acids of all cooked samples increased. Results suggested that grilling and steaming had beneficial effects on the protein quality of chub mackerel.

• Journal of Aquaculture
• /
• v.21 no.4
• /
• pp.213-217
• /
• 2008

This study investigated the effect of supplement of the pigment source in diets on body color for round tailed paradise fish Macropodus chinensis and the pale chub Zacco platypus. Fish (the round tailed paradise fish: 1.6 g/ fish, pale chub: 2.4 g/fish) were fed diets containing various pigment sources (Porphyra powder, Spirulina powder. yeast astaxanthin and paprika extract) twice a day for 6 weeks. Survival of all treatments was above 80%. Weight gain and total carotenoid contents of round tailed paradise fish fed the diet containing Porphyra powder was higher than that of fish fed the other diets. The apparent redness of skin and fin in round tailed paradise fish fed the diets containing paprika extract and yeast astaxanthin was better than that of fish fed the diets containing Porphyra powder, Spirulina powder and the control diet. Weight gain and total carotenoid contents of pale chub fed the diet containing paprika extract were higher than that of fish fed the containing Porphyra powder, yeast astaxanthin, Spirulina powder and the control diet. The apparent redness of skin and fin in pale chub fed the diets containing parika extract and yeast astaxanthin was better than that of fish fed the diets containing Porphyra powder, Spirulina and the control diet. The results of this study suggest that dietary supplementation with paprika extract and yeast astaxanthin can improve redness of skin and fin of round tailed paradise fish and pale chub.

• Animal Systematics, Evolution and Diversity
• /
• v.26 no.2
• /
• pp.105-114
• /
• 2010

A study of Han River fish assemblage dynamics for 4 years was conducted. From April 2005 to August, 2008, fishes inhabiting two sites of Han River were sampled for identification. For further analysis, 40 individuals of the dominant species were sampled monthly from March 2006 to November 2008. The fish assemblage at site 1 was dominated by Zacco platypus (32.69%), while the subdominant species were Acheilognathus yamatsutae (14.4%), Acanthorhodeus gracilis (9.43%), Squalidus japonicus coreanus (6.84%), and Tridentiger brevispinis (5.18%). The most abundant species at site 2 was Korean Chub (Zacco koreanus) with relative abundance of 62.45% and followed by Pungtungia herzi (10.29%), Coreoperca herzi (8.67%), and Coreoleuciscus splendidus (6.82%) as the subdominant species. At both sites, the endemics populations show an increasing pattern during the whole survey period, while the natives were declining in the last two years.

• Applied Microscopy
• /
• v.25 no.3
• /
• pp.63-74
• /
• 1995

The development of pale chub oocyte from the immature oogonium to mature oocyte was investigated by light and electron microscope. The cytoplasm of pale chub oogonia was acidic and many vesicles were located at inner side of nuclear membrane. In primary oocytes, yolk vesicles were distributed in cytoplasm. Also, fibrous materials and protuberances were distributed on the surface of zona radiata. The nucleus of secondary oocyte was enlarged and yolk vesicles in cytoplasm migrated to zona radiata. In early egg, yolk mass are formed and yolk vesicles were located at inner side of zona radiata. Three-layered zona radiata was about $3{\mu}m$ in thickness. The three layers were an outer fibrous material layer, a middle nurse cell layer in which microvilli of early egg cytoplasm contact with processes of nurse cells, and an inner layer with high electron density. In mature egg, euchromatin and a germinal vesicle were developed, mitochondria, free ribosomes, and yolk mass were distributed in cytoplasm. But, yolk vesicles were disappeared. Specially, zona radiata of matured eggs were better thin than the one of immature eggs In conclusion, it is summerized that the oogenesis of pale chub were the increase of cell size, the formation and accumulation of yolk, the decrease in nucleat electron density, changes of zona radiata, and the development of microvilli.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.41 no.1
• /
• pp.26-31
• /
• 2008

The feeding habits of chub mackerel (Scomber japonicus) were studied based on an examination of the stomach contents of 512 specimens collected between November 2005 and October 2006 in the South Sea of Korea. The specimens ranged in fork length (FL) from 23.4-37.5 cm. Chub mackerel is a piscivore and consumes mainly Teleosts such as Engraulis japonicus. Its diet also includes amphipods, crabs, Euphausia, chaetognaths and shrimp. Smaller individuals (<26 cm FL) consume mainly crabs. The proportion of these prey items decreases with increasing fish size, and this decrease paralleles the increased consumption of fish. The prey size increases with S. japonicus size.

• Korean Journal of Ichthyology
• /
• v.17 no.2
• /
• pp.98-104
• /
• 2005

Integumentary structures of the chub mackerel (Scomber japonicus) were examined by light and transmission electron microscopy. The integument of the fish was composed of epidermal and dermal layers. The epidermal thickness is about $20{\mu}m$ in TL 35~40 cm fish. The epidermal layer could be classified into superficial, intermediate, and basal layers by morphology and position of the supporting cells. The epidermal layer also possessed mucous cells, club cells and chloride cells. The area of secretory cells, including mucous and club cells, is about 23% of the epidermal layer. The mucous materials were identified as sulfated glycoprotein, neutral and acid in nature. Club cells had a large central vacuole and rough endoplasmic reticula in the cytoplasm. Chloride cells had numerous tubular mitochondria in the cytoplasm. The dermal layer consists mainly of collagenous fiber, and it contains fibrocytes, pigment cells and cycloid scales.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.48 no.2
• /
• pp.107-117
• /
• 2012

Korean large purse seine fishery catches chub mackerel, sardine, jack mackerel, Spanish mackerel, etc. which are mainly pelagic fish species. The proportion of chub mackerel was 60% over in Korean large purse seine fishery. Sea surface temperature (SST) increased $0.0253^{\circ}C$ per year and total rising rate was $0.759^{\circ}C$ from 1980 to 2009 in the southern sea of Korea, where is mainly fishing grounds of Korean large purse seine. It was that p<0.01 level was statistically significant. It is northward movement that the center of fishing grounds of chub mackerel by Korean large purse seine fishery moved 4.57km/yr. It was rapidly northward movement about 7.1km/yr, 8.13km/yr to move Spanish mackerel and bluefin tuna fishing grounds. However, the fishing grounds of jack mackerel were moved further south in the 2000s than the 1980s. Catch of tunas and bluefin tuna consistently increased in Korean waters. There was a significantly positive correlation between SST and catch of bluefin tuna in the fishing grounds of Korean waters.

• Economic and Environmental Geology
• /
• v.55 no.1
• /
• pp.19-27
• /
• 2022

Fish that inhabited in the watersheds of Andong, Imha and Yeongju Dam in the upper Nakdong River were analyzed heavy metals by separated into muscle, gill, stomach and liver part. Thirteen fish species such as dark chub, skygager, coreoperca herzi, Korean piscivorous chub, cornet fish, Japan crucian carp, catfish, bass, crucian carp, mandarin fish, carp, long-nosed barbel, Korean sharpbelly were analyzed using ICP/MS. The results of the analysis based on the overall average concentration showed that the muscle part is lower than other parts in all heavy metal items except mercury. The gill part showed high concentrations of chromium, manganese, nickel, and lead, the stomach part has high zinc, and the liver part showed high concentrations of iron, copper, arsenic, and cadmium.

• Korean Journal of Ichthyology
• /
• v.33 no.2
• /
• pp.64-73
• /
• 2021

We examined the growth and age structure for chub mackerel caught by a large purseseine in the Korean waters from January to December 2015. A total of 459 specimens were used for otolith analysis, ranging from 19.6 cm to 46.0 cm in fork length. Translucent zone was regarded as an annual mark, and age was counted using the information of the number of translucent zone, capture date, edge type of the otolith and nominal birthdate of 1 January. Annuli in otoliths were mainly formed in May, coinciding with the spawning season. Estimated ages were 0~6 years, and the von Bertalanffy growth models were not significantly different between male and female. Sex-combined growth model was obtained as FL_t=39.3×{1-exp[-0.90×(t+0.033)]}. Among the chub mackerel caught in 2015, the age 2 group had the highest proportion (30.9%), and the age 0 to 2 group accounted for 88.5% of the total catch.