Ocean Perch Research Articles

Phosphoglucomutase polymorphism in Pacific ocean perch, Sebastodes alutus

1.1. Three phenotypes of phosphoglucomutase were found in muscle extracts of Pacific ocean perch (Sebastodes alutus) by starch gel electrophoresis.2.2. Evidence for nonrandom distribution of phenotypes with regard to depth at which samples were taken, sex and alleles of α-glycerophosphate dehydrogenase is presented.

Reproductive Patterns of Pacific Ocean Perch (Sebastodes alutus) off Washington and British Columbia and their Relation to Bathymetric Distribution and Seasonal Abundance

Females of the ovoviviparous species Sebastodes alutus release their larvae in March in the Washington–British Columbia area. Male maturity data from Queen Charlotte Sound indicated that males probably inseminate females in September or October. Examination of the annual bathymetric cycle in three major commercial trawling areas showed that mating and insemination occur while Pacific ocean perch are moving to deep water from the shallow-water regions inhabited in summer and that females release their larvae while in the deepest part of their bathymetric range.Total 1955 through 1965 catch by month, and 11-year mean monthly catch rates were used to indicate relative seasonal abundance on major fishing grounds. Where deepwater regions were trawled, these indices showed a spring maximum associated with the March spawning period. In all areas studied there was a midsummer slump in catch and catch rate, and an October maximum occurring during the suggested mating period.

Parasitic Copepods of Sebastodes alutus Including Chondracanthus triventricosus sp.nov. and Colobomatus kyphosus sp.nov.

Sixty-six specimens of Sebastodes alutus, the Pacific ocean perch, collected from the coast of Oregon and British Columbia were examined for parasitic copepods. The six species identified are Chondracanthus pinguis Wilson, 1912, Chondracanthus triventricosus sp.nov., Clavella parva Wilson, 1912, Brachiella robusta (Wilson 1912) Kabata, 1970, Colobomatus kyphosus sp.nov., and Sarcotaces arcticus Collett 1874. Colobomatus kyphosus is the second species of the genus to be described from the eastern Pacific and Ch. triventricosus is the second chondracanthid to be found in nasal cavities. Sarcotaces arcticus is reported as a parasite of S. alutus for the first time. Details of the appendages of each new species are described and illustrated.

Survey of Rockfishes, Especially Pacific Ocean Perch, in the Northeast Pacific Ocean, 1963–66

During 1963–66, a trawl and echo-sounder survey was conducted in the northeast Pacific Ocean to investigate the distribution and abundance of rockfish (Scorpaenidae) species, particularly Pacific ocean perch (Sebastodes alutus), inhabiting the outer continental shelf and upper continental slope from Cape Blanco, Oregon, to Unalaska Island, Alaska. Rockfish predominated in most trawl catches. Among areas, numbers of rockfish species declined northward, from 19–21 in the Oregon–Vancouver Island region to 5 off Unalaska Island. Within areas, maximum numbers of species were caught at intermediate depths — usually 80–139 fath (146–254 m). With rare exceptions, Pacific ocean perch was the predominant rockfish species in the trawl catches throughout the study area, although its relative abundance declined from north to south.Within areas, ocean perch catch rates were usually maximal at intermediate depths — 120–139 fath (220–254 m) in summer and substantially deeper in winter. Juvenile fish usually occupied shallower depths than adults, but were often in the company of large adults. Among areas, summer catch rates were relatively high off southwest Vancouver Island and southeastern Alaska and in the western Gulf of Alaska. Off Vancouver Island, summer catch rates were higher than winter catch rates, particularly for large adults of both sexes. Echo-sounder records indicated schools were frequently unavailable to the on-bottom trawl used in this survey.Ocean perch in the northeast Pacific Ocean were categorized, tentatively, into B.C.- and Gulf-types, whose mutual boundary is Dixon Entrance. Separation was based on differential size distributions and year-class strengths.Survival rates among year-classes were evidently quite variable, particularly for the Gulf stock west of Cape Spencer.Qualitatively, ocean perch abundance generally increased from south to north in the study area.Bottom-water temperatures varied inversely with depth and latitude. Among areas, temperature range at depths of maximal ocean perch catch rate was 4.5–7.7 C, but in high-abundance areas the temperatures did not exceed 6.0 C. Seasonally, temperature at depths of maximal catch rate varied approximately 1.5 C.

Keeping Time of Frozen Redfish (Sebastes marinus mentella) Fillets in Relation to Handling of the Raw Material and Storage Temperatures after Processing and Freezing

The effect of various periods of prefreezing storage for iced, whole redfish (Sebastes marinus mentella) on the frozen-storage keeping times (at −23 C) of the fillets and the effect of various periods of fillet storage at temperatures equal to and higher than −23 C are reported. The fish were caught on the Grand Bank and on Banquereau in May and June. Assessment was by taste panel with chemical tests for protein solubility, rancidity, and pH made for purposes of comparison.Fish iced 2 days, then processed and frozen, were of acceptable quality for 83–94 weeks; those iced for 12 days, then filleted and frozen, had a storage life to unacceptability of 51 weeks. Samples processed and frozen after 4 days in ice and subjected to variation in temperature (−23 C; −12 C) during initial frozen storage, then stored at a final temperature of −18 C, as in transportation aboard a refrigerated vessel and in cold storages used in the marketing chain, had initial quality characteristics similar to fish iced for 12 days (then processed and frozen) but had a shorter storage life to unacceptability, 44 weeks. Fish iced 15 days were unacceptable for freezing.

IRRADIATION OF PACIFIC COAST FISH AT SEA

An experimental shipboard irradiator was installed aboard the Bureau Of Commercial Fisheries research vessel Miller Freeman and utilized to irradiate West Coast fish at sea. The optimum dose range for irradiating whole English sole (Parophrys vetulus), Dover sole (Microstomus pacificus), Pacific cod (Gadus macrocephalus), Pacific ocean perch (Sebastodes alutus), and black rockfish (Sebastodes melanops) is in the range of 50 to 100 kilorads. The shelf life (at a high level of quality) of the irradiated products was extended by one and one-half to two times that of the nonirradiated samples. Among the five species irradiated at various states of rigor, prerigor-rigor fish generally had better storage characteristics than postrigor fish.

Analysis of arsenic and selenium in marine raw materials.

AbstractThe content of arsenic and selenium has been analysed in the following marine organisms: cod (Gadus morhua), herring (Clupea harengus), mackerel (Scomber scomber), Norway haddock (Sebastes marinus), lobster (Homarus vulgaris), mussel (Mytilus edulis), clam (Pecten maximus), oyster (Ostrea edulis), squid (Ommastrephes sagittatus) and whale (Balaenoptera physalus). The analyses were performed both on the raw material and in the water‐soluble phase after the samples had been boiled (the N liquor). An enrichment of arsenic is observed in the N liquor, compared with the raw material. The results indicate that selenium is also enriched in the N liquor from fish, but not from the invertebrate animals analysed.The N liquor and the water‐soluble phase of the enzyme‐hydrolysed presscake (the water‐insoluble phase after boiling) were fractionated by molecular gel nitration. Fractions from these elutions were analysed for arsenic and selenium. Selenium was present in the fractions with a molecular weight above about 5000. Arsenic was connected with the lower molecular weight fractions, and may be present as more arseno‐organic compounds.

Electrophoretic Variants of L-Alpha-Glycerophosphate Dehydrogenase in Pacific Ocean Perch (Sebastodes alutus)

Three phenotypes of L-alpha-glycerophosphate dehydrogenase (α-GPDH) were found in muscle extracts of Pacific ocean perch by starch-gel electrophoresis. No association was obvious between alpha-glycerophosphate phenotype and sex or stage of maturity. The observed phenotypes were presumed to be under the control of two allelic genes, F and S. This assumption was supported by the distribution of phenotypes of fish collected off the coasts of Washington and Oregon. This report is the first on genetic variants of an enzyme in Pacific ocean perch and suggests that isozymes of α-GPDH may be useful in population studies of this species.

Direct Determination of the Thiobarbituric Acid Value in Trichloracetic Acid Extracts of Fish as a Measure of Oxidative Rancidity

AbstractThe possibilities of the direct determination of the thiobarbituric acid (TBA) value in trichloracetic acid (TCA) extracts instead of distillates were evaluated. Tests carried out on herring (Clupea harengus L.), redfish (Sebastes marinus L.), cod (Gadus morhua L.), plaice (Pleuronectes platessa L.) and spurdog (Squalus acanthias L.) of varying degree of oxidation gave 95.3% recovery in the teleost species but only 75.2% in the elasmobranch spurdog, due to the urea present. With the distillation technique, recoveries were lower and averaged 66.1% for teleosts and 43.0% for spurdog. Addition of 0.1% of both propyl gallate and EDTA to the TCA solution lowered TBA values by 25 to 59%. When fish samples were submitted to a 4 hours′ forced oxidation period, TBA values increased to a greater extent with the direct extraction procedure than with the distillation method.

Effect of EDTA Treatment on Spoilage Characteristics of Petrale Sole and Ocean Perch Fillets

Ethylenediaminetetraacetic acid (EDTA) used in 1% solution as a dip extended the 0.5-C shelf life of petrale sole and ocean perch fillets by repressing growth of Pseudomonas spoilage organisms and formation of trimethylamine. Of the three salts compared, Na2EDTA and Na4EDTA were the most effective, extending shelf life of ocean perch fillets by 7–10 days, whereas Na2CaEDTA gave a 4-day extension over the control fillets. Vacuum packaging enhanced the effectiveness of EDTA as a preservative.

ベーリング海におけるアラスカメヌケの鱗相-II

ベーリング海におけるアラスカメヌケの鱗相-II

ベーリング海におけるアラスカメヌケの鱗相-I

The scale characters of Pacific Ocean Perch, Sebastodes alutus, and its variations by body regions were investigated for two specimens caught in the Bering Sea in 1965 (Table 1 and Fig. 1). The scale is of a ctenoid type by many characters recognized on the surface of scale (Fig. 2). There are many ridges concentrically around the central plate on the covered portion. The widely spaced ridge zone and the close one appear alternately, and they are considered to be the growth zone and the resting zone respectively (Figs. 2 and 3). The radius of the resting zone, measured from the converged point of grooves to the each outer edge, shows a smooth curve (Fig. 4), but the cumulative number of ridges indicates a inflective line (Fig. 7). The resting zones are supposed to be formed periodically from the Walford's graphic method for their radii (Fig. 6). These characters aforementioned were observed similarly on every scale of the same fish irrespectively of samlping region, and of the shape and the size of scale (Fig. 4, 5, 6 and 7). Therefore, there is a good possibility for determining the age of S. alutus by the scale character, and so far as age determination is concerned, there is no need of strictly defining of scale sampling region.

Sampling Research Trawl Catches at Sea

During 1963 and 1964, studies were conducted aboard the research vessel G. B. Reed to test schemes for sampling individual trawl catches of groundfish, principally Pacific ocean perch (Sebastodes alutus), for size composition, weight and numbers caught, and sex ratio. A species sort into tub lots preceded sampling. Empirical tests were used to evaluate sampling methods for all parameters except sex ratio. Size composition and sex ratio samples were evaluated with chi-square tests. Estimates of weight and numbers caught were arbitrarily evaluated on the basis of their percentage deviations from actual values.For ocean perch the size composition, weight caught, numbers caught, and sex ratio were best estimated from a stratified sample consisting of the first 2, middle 2, and last 2 full tubs weighed. For 21 test hauls, the error range for weight estimates was −6 to +5%; for estimated numbers caught, −5 to +4%. Sex ratio was homogeneous among tubs within hauls.For six other groundfish species, weight caught was satisfactorily estimated from a serial sample consisting of the first 6 full tubs weighed, providing the tubs within hauls were filled uniformly. For 13 tests, the error range was −3 to +1%.

Selection of microbial population in chlortetracycline-treated ocean perch (Sebastodes alutus).

Microorganisms isolated from chlortetracycline (CTC)-treated ocean perch were individually tested to determine their relative sensitivity to CTC by use of CTC-impregnated paper discs. The CTC sensitivity varied among isolates obtained from untreated fish. The proportion of CTC-resistant species increased with higher CTC concentration and the length of storage at 7 C. Among individual generic groups, "coryneforms" and yeasts were more resistant to CTC than other groups. Pseudomonas, Achromobacter, Flavobacterium, Bacillus, and Lactobacillus all contained species either resistant or sensitive to CTC. More CTC-resistant species in these genera accumulated with the increased CTC concentrations and with the length of storage in the presence of CTC.

Comparative effects of chlortetracycline, freezing, and gamma radiation on microbial population of ocean perch.

The microbial populations in chlortetracycline (CTC)-treated (50, 100, 200, and 500 ppm), frozen (-15 C), and irradiated (0.1 Mrad) ocean perch (Sebastodes alutus) were compared. The control sample spoiled at 7 C, primarily because of the growth of Pseudomonas. Irradiation changed this to Achromobacter-dominated spoilage. Freezing or CTC treatment altered the spoilage pattern very little. CTC was particularly effective against ultraviolet fluorescent Pseudomonas species at the higher concentrations. Freezing and CTC were not effective against "coryneforms."

Comparative Effects of Chlortetracycline, Freezing, and γ Radiation on Microbial Population of Ocean Perch1

The microbial populations in chlortetracycline (CTC)-treated (50, 100, 200, and 500 ppm), frozen (-15 C), and irradiated (0.1 Mrad) ocean perch (Sebastodes alutus) were compared. The control sample spoiled at 7 C, primarily because of the growth of Pseudomonas. Irradiation changed this to Achromobacter-dominated spoilage. Freezing or CTC treatment altered the spoilage pattern very little. CTC was particularly effective against ultraviolet fluorescent Pseudomonas species at the higher concentrations. Freezing and CTC were not effective against "coryneforms."

Effects of Water and Dielectric Thawing Processes on Shelf Life of Double-Frozen Cod and Redfish

Analytical taste panel results showed that immersion-thawing in tap water at two different temperatures (7.2 and 15.5 C) and dielectric thawing (at 38 Mc/s) had similar effects on the cold-storage life (at −23 C) of processed, refrozen fillets of cod (Gadus morhua) and of redfish (Sebastes marinus mentella) (water thawing at 15.5 C only).Refrozen fillets from Grand Bank cod, captured in March, iced 4 days and frozen, water-thawed, and reprocessed as above, though not quite as good as once-frozen controls, were still of good quality after 35 weeks storage.Lightly feeding June trap cod, captured in cool (4 C) inshore water, iced, and frozen before and during rigor mortis, then water-thawed and refrozen, were still acceptable after 28 weeks storage, but were considerably poorer than samples frozen once. Quality was similar at both thawing, temperatures (7.2 and 15.5 C) and both conditions of rigor at first freezing.Heavily feeding July trap cod, captured in warmer (7–9 C) inshore water, similarly handled and similarly processed and refrozen following thawing in water at 15.5 C or dielectrically, were of just acceptable quality up to 32 weeks in storage and were similar to samples frozen once.Grand Bank redfish, similarly frozen before and during rigor and later processed and refrozen, maintained very acceptable quality up to 28–34 weeks with both thawing procedures and state of rigor at freezing and were equal to samples frozen once. Thiobarbituric acid values increased on storage.

Selection of Microbial Population in Chlortetracycline-treated Ocean Perch (Sebastodes alutus)1

Microorganisms isolated from chlortetracycline (CTC)-treated ocean perch were individually tested to determine their relative sensitivity to CTC by use of CTC-impregnated paper discs. The CTC sensitivity varied among isolates obtained from untreated fish. The proportion of CTC-resistant species increased with higher CTC concentration and the length of storage at 7 C. Among individual generic groups, "coryneforms" and yeasts were more resistant to CTC than other groups. Pseudomonas, Achromobacter, Flavobacterium, Bacillus, and Lactobacillus all contained species either resistant or sensitive to CTC. More CTC-resistant species in these genera accumulated with the increased CTC concentrations and with the length of storage in the presence of CTC.

Occurrence of dimethyl-ß-propiothetin in marine phytoplankton : Ackman R. G., C. S. Tocher and J. McLachlan, 1966. J. Fish Res. Bd Can., 23 (3): 357–364.

The fatty acid and lipid class composition of the eyes and brain were determined for the following species: Atlantic cod (Gadus morhua), saithe (Pollachius virens), redfish (Sebastes marinus), Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), Portuguese dogfish (Centroscymnus coelolepis), black dogfish (Centroscyllium fabricii), and leafscale gulper shark (Centrophorus squamosus). Fatty acid analyses of eyes from teleosts in the present study indicated that the lean species contained high ratios of docosahexaenoic acid (DHA) versus eicosapentaenoic acid (EPA), and high ratios of n−3 fatty acids versus n−6 fatty acids, while these ratios were significantly lower for the fatty fish species. The lipid class analyses revealed that among both elasmobranchs and teleosts, phospholipid was the dominant class of lipids in the eyes of lean species, while triacylglycerol was the dominant class of lipids in fatty species. Analyses of the fatty acid composition of brains revealed that the deep-sea elasmobranchs, Portuguese dogfish, black dogfish, and leafscale gulper shark, contained a level of arachidonic acid (AA) that was higher than their level of EPA and about fivefold higher than what was found in the brains of teleosts. Such high levels of AA are not normally observed in fish brains; rather, they are generally observed in brains of higher vertebrates.

Brown discoloration in pre‐rigor cut fish fillets

SummaryThe surface browning in pre‐rigor processed cod fillets has been shown to be caused by the formation of a denatured form of methaemo‐globin produced from fish blood contaminating the surface. Browning is less likely to occur in fillets cut in rigor or later because a pre‐rigor cut surface exudes a coagulum in which blood is trapped and from which it cannot be easily removed by washing. The observation that Ocean Perch is more liable to surface discoloration has been explained in terms of differences in blood distribution in the muscle tissue. Cod haemoglobin differs markedly from mammalian haemoglobin in that oxyhaemoglobin changes to deoxyhaemoglobin as the pH is reduced below 8. Mammalian haemoglobin is stable at all pH values between 10 and 4.It is suggested that surface browning in fish fillets can be prevented by using correct bleeding procedures before filleting, or by filleting in rigor or later.