• Fisheries and Aquatic Sciences
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• v.17 no.1
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• pp.85-93
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• 2014

A 9-week feeding experiment was designed to test the effects of the dietary inclusion of distillers dried grain (DDG) on the growth performance, body composition, and antioxidant activity of juvenile rockfish Sebastes schlegeli. Five isonitrogenous and isocaloric diets were formulated to contain 0% DDG (DDG0), 7% and 14% DDG from rice (diets DDG-R7 and DDG-R14, respectively), as well as 7% and 14% DDG from rice and wheat flour (diets DDG-RW7 and DDG-RW14, respectively). Three replicate groups of juvenile rockfish averaging $68.0{\pm}0.4g$ were fed one of the diets to apparent satiation twice a day. Survival, weight gain, feed efficiency, and the protein efficiency ratio of fish were not affected by dietary DDG (P > 0.05). Proximate and amino acid compositions of the whole body were not affected by dietary DDG (P > 0.05). Plasma total protein, glucose, total cholesterol, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, phospholipid, and triglyceride were not affected by dietary DDG (P > 0.05). Radical scavenging activity on 1,1-diphenyl-2-picryl-hydrazyl (DPPH) in the plasma of rockfish fed the DDG-RW14 diet was higher than that of fish fed the DDG0 diet (P < 0.05). Hydroxyl radical scavenging activity in the liver of rockfish fed diets containing DDG was higher than that of fish fed the DDG0 diet (P < 0.05). Alkyl radical scavenging activity in the liver of rockfish fed the DDG-R7 diet was higher than that of fish fed the DDG0 diet (P < 0.05). These results suggest that DDG is a suitable ingredient for the partial replacement of wheat flour and can be used at a rate of up to 14% in the diet without incurring negative effects on the growth performance or body chemical composition of juvenile rockfish.

• Journal of fish pathology
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• v.22 no.2
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• pp.137-146
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• 2009

The black rockfish Sebastes schlegelii neutrophil cytosolic factor components p47 phox (phagocyte oxidase) cDNA was cloned. The sequence of the cDNA showed that rockfish p47 phox cDNA consisted of 1,952 bp contained open reading frame encoding predicted polypeptide of 420 amino acids. Additionally analysis of the p47 phox amino acid sequence showed two potential SH3 domains. The functional domains are highly conserved in many animals, though the sequence of the components of the black rockfish showed low homology with that of mammals. The deduced amino acid sequence of the black rockfish p47 phox was similar to those of the carp (60.4%), zebrafish (59,2%), rainbow trout (68.5%), xenopus (55.2%), mouse (54.2%), rabbit (54.5%), rat (53.7%), and chicken (50.9%). The expression of the rockfish p47 phox molecule was induced in peripheral blood leukocytes (PBLs) from 1 to 12 h following LPS stimulation, with a peak at 6 h after the stimulation, and which increased at 1, 3, and 12 h after treated with Poly I:C compared with the control. The rockfish p47 phox gene was expressed in various tissues of healthy fish. The level of p47 phox expression was high in the PBLs, kidney and spleen.

• Ocean Science Journal
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• v.43 no.2
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• pp.107-113
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• 2008

Laboratory bioassays were conducted to test the acute toxicity effects of sudden exposure to sodium cyanide (NaCN) on the endogenous rhythm of the oxygen consumption rate (OCR) in the black rockfish Sebastes schlegeli. The OCR of the black rockfish(n = 14, total length = $20.4{\pm}1.16\;cm$, wet weight = $158{\pm}25\;g$) was measured with an automatic intermittent-flow-respirometer. OCR decreased significantly when experimental fish were exposed to NaCN. When exposed to 10 ppb NaCN, fish were able to recover their OCR rhythmic activities. When fish were exposed to 20 ppb, however, the metabolic activity rhythms were not recovered. These results suggest that exposure to NaCN concentrations over 20 ppb cause severe physiological damage to the endogenous rhythms of black rockfish.

• Journal of Environmental Health Sciences
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• v.29 no.4
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• pp.17-20
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• 2003

The results of study of the parasites of rockfishes, Sebastes spp. collected at Oregon coast aquarium during April 6 to June 30, 2002 are presented. Six species of parasites were recovered from examination of 19 rockfishes with an incidence of infection of 42.1 %. This study investigated parasitic infestation of 7 black rock-fish, Sebastes melanops ; 3 quillback rockfish, S. maliger ; 2 yellowtail rockfish, S. flavidus ; 3 canary rockfish, S. pinniger 2 yelloweye rockfish, S. ruberrimus ; 2 tiger rockfish, S. nigrocinctus. Sebastes spp. from aquarium were found to be infested with parasites: Mycrocotyle sebastis, Megalocotyle trituba, Clavella uncinata, Anisakis simplex larvae, Contracaecum sp. larvae, Pseudoterranova decipiens larvae. Prevalence and mean intensity of rockfishes were infected respectively as follows: 21.1%, 4.0 of M. sebastis, 10.5%, 55.5 of M. trituba, 21.1%, 34.3 of A. simplex larvae, 10.5%, 15.0 of Contracaecum sp. larvae, 10.5%, 8.5 of Pseudoterranova decipiens larvae and 10.5%, 5.0 of Clavella uncinata. This study reveled that gills and gastrointestinal tracts of S. pinniger were heavily infested with M. trituba and A. simplex larvae.

• Korean Journal of Environmental Biology
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• v.20 no.4
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• pp.300-302
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• 2002

The occurrence and infection level of parasitic Copepod, Clavella adunca on the black rockfish, Sebastes melanops at the Hatfield Marine Science Center Aquarium were studied. C. adunca was usually found on the base of fins, preferably on the pectoral fins. Seven specimens of black rockfish, Sebastes melanops were collected from Oregon Coast Aquarium. Copepods of ten Clavella adunca were present as ectoparasites attached to the fins in the black rockfish. The prevalence and relative density of Clavella adunca were 28.6% and 1.4 respectively. It is considered that the tissue of the fin membrane offers the most favorable conditions toy the attachment of C. adunca.

• Journal of Environmental Health Sciences
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• v.28 no.5
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• pp.102-105
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• 2002

The gills of seven black rockfish, Sebastes melanops collected from Hatfield Marine Science Center Aquarium during September 19-October 3,2001 were examined for parasites attached to the gills. The species of Sebastes melanops were Microcotyle sebastis baled on the number of clamps and testes. The prevalence of 42.9％ was recorded for host and fourteen worms of three black rockfish were recovered. Mean intensity of infection of Microcotyle sebastis individuals per infected host for black rockfish was 2.0(range 1-11). Monogenea helminth sites were mainly consist of second and third gill arch's filaments of black rockfish. The results revealed that surface area of the 2nd and 3rd pair of gills might affect the distribution of Microcotyle sebastis.

• Fisheries and Aquatic Sciences
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• v.6 no.2
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• pp.59-65
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• 2003

The critical thermal maximum (CTM) of black rockfish, Sebastes schlegeli, was evaluated. Black rockfish were acclimated at $24^{\circ}C$, and then exposed to temperatures from 24 to $33^{\circ}C$. Black rockfish were kept in constant darkness and subjected to a gradual temperature increase $(1 ^{\circ}C\;12^{-1})$. The oxygen consumption rate (OCR) was measured using an automatic intermittent­flow-respirometer (AIFR) during the exposure period (from 119.3 to 143.5 h). The OCR increased from 94.5 to 214.2mL $O_2 kg^{-1}\;ww\;h^{-1}$ as the temperature rose from 24 to $29.4-30.9^{\circ}C$. Subsequently, the OCR increased abruptly, reaching 245.8-412.7mL $O_2 kg^{-1}\;ww\;h^{-1}$ at $32^{\circ}C$. This study suggests that the CTM for black rockfish is $29.4-30.9^{\circ}C$ when temperature is increased at $1^{\circ}C\;12h^{-1}$ following acclimation at $24^{\circ}C$.

• Journal of Aquaculture
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• v.11 no.3
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• pp.345-352
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• 1998

The effect of starvation on the growth and hepatocyte nuclear size of larval rockfish Sebastes schlegeli and spotted sea bass Lateolabrax sp. were studied. The growth of total length and wet weight in both rockfish and spotted sea bass starved were lower than their control counter-parts. The nuclei sizes of parenchymal cells in the liver of rockfish and spotted sea bass were correlated with the nutritional status of their first-feeding larvae. The result suggested that hepatocyte nuclear size in rockfish and spotted sea bass could be used as an alternative indicator for the identification of starving condition and such karyometry might be criteria for evaluating the successful transition from endogenous to exogenous feeding regime.

• Journal of fish pathology
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• v.22 no.3
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• pp.343-352
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• 2009

Natural-killer-cell-enhancing factor (NKEF) belongs to the newly defined peroxiredoxin (Prx) family. It was originally isolated from human erythroid cells. The black rockfish NKEF cDNA was identified through the expressed sequence tag (EST) analysis of PBLs libraries. The full-length NKEF cDNA was 1433 bp long and contained an open reading frame (ORF) of 594 bp that encoded 198 amino-acid residues. The 5' UTR had a length of 39 bp, and the 3’UTR 800 bp. The deduced amino-acid sequence of the black rockfish had a density 93.4, 92.9, 87.8, 85.8, 84.8, 83.8, 80.3, 79.7, 77.2, and 75.2% that of the pufferfish, olive flounder, channel catfish, zebrafish, chicken, common carp, Myotis lucifugus, cattle, human PrxI, rat PrxI, human NKEF-A, and Xenopus tropicalis, respectively. The NKEF gene was expressed in all the tissues of the black rockfish. The RT-PCR indicated that the NKEF transcripts were predominantly in the spleen and gill, less dominantly in the PBLs, head kidney, trunk kidney, and liver, and least in the intestine and muscles. This is the first report on the existence of the NKEF-A gene in black rockfish.

• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.420-429
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• 2023

This study was designed to examine the immune response in Korean rockfish during water temperature fluctuation and to elucidate the factors contributing to streptococcal pathogenesis in cultured Korean rockfish, S. schlegeli. We investigated cumulative mortality against Streptococcus iniae (FP5228 strain) infection in the exposed Korean rockfish (39.7±5.8 g) to environmentally relevant temperature (Control, 23℃; High temperature, 28℃ and 23℃ and 28℃ with 12 hours interval exchange, 23↔28℃) for 48 hours. Also, the expression of the mRNA related to the immune response genes (heat shock protein 70, interleukin1β, lysozyme g-type and thioredoxin-like 1) were measured in spleen and head kidney by real-time PCR analysis in the exposed fish to thermal stress. In this study, the combined stress with bacterial challenge in fishes exposed to thermal stress lowered the survival rate than that of control (23℃). The cumulative mortality in the group of control, 28℃ and 23↔28℃ was 24%, 24% and 40% (P<0.05), respectively. Also, thermal stress modulated the mRNA level of immune related genes; heat shock protein 70, interleukin-1β, lysozyme g-type and thioredoxin-like 1 in Korean rockfish. The present study indicates that a high and sudden water temperature change affect immune responses and reduce the disease resistance in Korean rockfish.