Relationships between the size of fertilized eggs and characteristics such as weight, length and stages of development of hatched embryos and emerged alevins in chum salmon were studied. Eggs weighing from 150 to 400mg taken from chum salmon returning to the Tsugaruishi River in Iwate Prefecture were incubated at 11.0±0.5°C. The entire body weight, tissue weight, yolk weight, length, and developmental stages were compared among different size groups of the eggs at the hatching times and emergence. Irrespective of their differences in size at fertilization, eggs required almost the same duration for hatching and emergence. As was expected larger embryos gave larger alevins emerging at a less developed stage and with a greater condition factor whlie the smaller embryos gave smaller alevins emerging at a more advanced stage and with a lesser condition factor. Thus the larger alevins originating from larger eggs seem to have advantages in their early life history becauseof their energy rich condition. Disadvantages of the smaller alevins might be compensated by the relatively high fecundity and by their higher swimming activity at their emergence by more advance development.

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Monoclonal antibody (mAb) YeT-2 was generated in mice hyper-immunized with thym c lympho-cytes of yellowtail Seriola quinqueradiata. The mAb YeT-2 reacted withthe major population of peripheral blood lymphocytes, but not with serum IgM. OnPercoll density gradientcentrifugation, YeT-2 positive cells were distributed at densities of 1.058 and 1.064. The latter density layer also included some YeT-2 negative cells. Furthermore, on electron microscopic studies, YeT-2 positivelymphocytes in peripheral blood could not be distinguished from YeT-2 positivelymphocytes in thymus. Flow cytometric analysis showed that mAb YeT-2 positivelymphocytes comprised 88.4% and 76.1% of the peripheral blood and thymus, respectively. Functional studies revealed that YeT-2 positive lymphocytes respond to concanavalin A but not to lipopolysaccharide, while YeT-2 negative lymphocytes responded in the opposite way. From these results, it can be concluded that the novel mAb YeT-2 recognizes a lymphocytic population which might be the putative T cell.

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The number of entrapped prawns in a pot may be controlled by the funnel entrancedesign. The catching ability of small prawn pots was studied. To clarify how thepot funnel design affects the number of prawns in a pot, a series of test werecarried out with model pots withoutbait in the south-basin fishing ground of Lake Biwa, Japan. The data used in the evaluation were the catch of 249 test trials by prawn pots in six years (2 October 1986-26 December 1991). The variations in therelative catching index, R_i, could be explained satisfactorily by the differences in the funnel designs.
The pot used here had a characteristic effect forany one funnel design on the number of prawns entrapped. The results suggest that the diameter of the opening and the height of the funnel strongly control the number of entrapped prawns.

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Although dimethyl sulfoxide (DMSO) has been often used in cryopreservation of f sh embryo as an effective cryoprotectant, its maximum concentration in terms of its toxicity wasobscure. When the embryos of several fish species, medaka, pejerrey, rainbow trout and carp, were immersed in solutions of various DMSO concentrations, the amounts of DMSO penetrating into the embryos were measured by HPLC and simultaneously their mortalities were determined from observation undermicroscope. From the uptake curves of DMSO, the permeability coefficients of DMSO to the eggmembrane were estimated to be 0.13 to 1.09×10-4cm/sec. Furthermore, the relations of accumulative mortality v. s. DMSO concentration in embryos were well expressed by a cumulative normal distribution function, and the averageDMSO lethal concentration of each embryo, giving a cumulative mortality of 50%, and its variance were determined. It was concluded that the tolerance to DMSO becomes higher in the order of carp, rainbow trout, pejerrey, and medaka.

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Each group of normal males and sexreversed gynogenetic females (phenotypical m le) of hirame Paralichthys olivaceus were crossed with normal females, and the obtained larvaeand juveniles were reared at two different water temperatures of 18°C and 23-25°C (only normal generation) during the sex determination period. When lower growing fish (about 20mm in total length) appeared in their original populations, these were separated and reared in other tanks. The popul tions reared at 18°C without growth retention indicated the primary genetic sex ratio, while the populations reared at high temperatures showed clearly lower proportionsof females. The lower growing fish showed lower proportions than those in the original group, at both water temperatures. These results show that the sex ratioof a pond population is greatly affected not only by rearing water temperature, but also by the existence of lower growing fish.

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The ovarian morphology, annual reproductive cycle and spawning characteristics fthe kichiji rockfish Sebastolobus macrochir collected from the Pacific coast of southeasternHokkaido, was examined on the basis of histological observation. The ovaries of this fish are categorized as cystovarian type. The ovarian parenchyma, stroma, and blood vessels run longitudinally through the center of each ovary, suggesting a specialized structure for formation of gelatinous egg masses.
The female kichiji rockfish begins vitellogenesis from August to October, and continues yolk accumulation until March. Post-ovulatory follicles or oocytes at final maturation stage were observed in March and April, suggesting that spawning was carried out mainly in this period.During the spawning season, there were two clutches of developing oocyte, or post-ovulatory follicleand one clutch of oocyte in the ovary. Therefore, females seem to spawn twice within a single spawning season. Fish which finished spawning rapidly form yolk vesicles for the next reproduction, and maintain a resting condition for several months.
Gonad somatic index (GSI) corresponds clearly to ovarian maturity, and could be divided into immature (GSI<2), spent (2<GSI<3), and vitellogenic or maturation (GSI>3) during the spawning season. This indicates that ovarian maturity can be evaluated on the basis of GSI. By this method, the minimum maturation size of the female kichiji was estimated to be 151 to 175mm in standard legth.

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Influence of contracture on the breaking strength was studied using caffeine contracture in ordinary carp muscle. The progressive speed of muscle contracture increased in caffeine contracture at lower temperatures and the contractile percentage of muscle attained maximum values for about 1 h. The breaking strength of muscle was larger in the maximum value of contractile percentage than immediately after death. The increasing rate of the breaking strength was in proportion to the percentage of muscle contracture and about 9 g per 1%.
In an experiment of rigor mortis, the maximum value of muscle contracture was very large in storage at 30°C, however, the breaking strength was much smaller in the maximum value of contractile percentage than immediately after death. In storage at 0 and 15°C, the maximum value of muscle contracture was small, and the breaking strength after storage in comparison immediately after death were either smaller or larger, and differed by the position of the muscle. As a result, the breaking strength did not correspond with contractile percentage of muscle in rigor mortis, indicating that this result was obviously different from that of caffeine contracture by the influence of tenderization.

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This study was conducted to determine digestible and metabolizable energy values(DE and ME) of eight practical diets and five commercial diets for carp. The proportion of DE to gross energy (GE) of the practical diets determined with large carp (150_??_300g) was 76.3_??_81.6%. The proportion of nonfecal energy losses to GE varied from 2.2 to 3.0%, leading to ME values ranging from 3.17 to 3.54 kcal/g. The ME/DE rates were 96.1_??_97.2% (96.7% on average).
In the next experiment, amino acid imbalanced diets were used to examine the effect of feeding levels on non-fecal energy losses in rainbow trout. In the fish fed diets having a low EAA index (68.8), the proportion of non-fecal energy loss to GE increased with decrease of the GE intake, suggesting a low ME value. It is inferred that not only amino acid absorbed but also tissue proteins are deaminated to yield energy.
Seven diets, in which the EAA index ranged from 83.8 to 89.7, were fed to carp and rainbow trout to determine the energy values of the diets. In both species the effect of the EAA index on the non-fecal energy loss was not great and the ME/DE rates were 98.5% in carp and 97.6% in rainbow trout on average.

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Competent pediveliger larvae (26-32 days old) of the mussel Mytilus edulis galloprovincialis attached and metamorphosed when exposed to microbial films but not to unfilmed surfaces. The inducing factor in the microbial film remained active after treatment with 5% formalin solution. However, microbial film lost activity to induce metamorphosis after autoclaving.
The films produced by specific strains of bacteria that were isolated from microbial film induced larval attachment and metamorphosis. The two bacterial strains (C 1.1 and C 4.1) which were most potent in inducing larval attachment and metamorphosis were identified with the Pseudomonas-Alteromonas group. This is the first report which demonstrates the direct involvement of specific bacterial strains in the attachment and metamorphosis of mussel pediveliger larvae.

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This paper analyzes mathematically the dynamic properties of a midwater trawl system which is composed of a trawler, trawl net, otter boards and warp. Taking the midwater trawl system of “SINYO Maru” of the Tokyo University of Fisheries as an example, the effects of changing towing speed and warp length on the system dynamics are demonstrated. The “overshoot” phenomenon caused by sinking of the otter board while lengthening the warp is clearly explained.

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Virus-like particles (VLPs) were found in several kinds of unicellular apochlorotic microorganisms in the electron microscopical samples obtained from three stations in the coastal water of Japan. All of the observed VLPs were icosahedral and 175-335 nm in diameter. Some of the host cells had apparent food vacuoles indicating that they were phagotrophic. These observations suggest that viral multiplication may effect the dynamics of unicellular apochlorotic microorganisms including heterotrophic nanoflagellates (HNF), grazers of bacteria.

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We developed a physiological method to open oyster shells persistently for use in an automated oyster shucking machine. When oysters (shell height, 10-13cm; shell length, 5-7cm; molluscous body weight, 9-22g) were submerged in 0.369m MgCl₂ solution, their adductor muscle began to relax persistently after 17±5.9min (mean+standard deviation) at a water temperature of 5°C and after 18±11.5min at 15°C. The muscle did not contract when the molluscous body was stimulatedwith a needle. After the oysters were transferred into artificial sea water, the muscle began to contract and the oysters resumed shell movement in 78±44.2min at 5°C and 24±5.4min at 15°C. When 120 individuals were submerged in MgCl₂ solutions at 17-18°C, cumulative persistent shell opening rates in the solutions of 0.369m and 0.738m were 14.2% and 63.3% for 30min submersion, 35.0% and 72.5% for 60min submersion, 64.2% and 83.3% for 120min submersion, and 76.7% and 85.8% for 180 minsubmersion, respectively. This method for opening oyster shells persistently with the use of Mg²⁺ will be applicable to other bivalves for opening shells by adjusting the Mg²⁺ concentration and submersion time for each species.

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Distribution of aerobic bacteriochlorophyll-containing heterotrophic bacteria (ABHB) was examined for the seawater of Otsuchi Bay, Iwate, in 1992 and 1993. In 1993, the population of ABHB was highest on July 22 and its percentage in total aerobic heterotrophic bacteria counted on agar plates ranged from ca. 20 to 50%. ABHB was present at lesser extents in August and September but not found in neither May nor October. Increase of ABHB population was coincident with the development of stratification in seawater, but did not seem to correlate with the change of solar radiation intensity. Higher proportions of ABHB were also found on July 14 of 1992, and were around 20%.

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The isozyme profiles of Porphyra were examined by means of polyacrylamide gel electrophoresis to establish a method for distinguishing Porphyra species. The conchocelis of Porphyra used in this experiment included P. tenera (Minomi), P. tenera (Matsukawa), P. yezoensis f. narawaensis, P. yezoensis (Saga10), P. yezoensis (Green), and P. seriata (Shimabara). Among the detected enzymes, the electrophoretic profiles of GOT, GDH, PGM, G6PD, ADH, and AK isozymes varied. In particular, the GOT profile distinguished P. tenera, P. yezoensis, and P. seriata, which was the wild type, whereas the AK profile differed in all six species. In addition, the GDH, PGM and ADH profiles distinguished all six species, when combined with those of GOT.
In conclusion, the GOT, AK, GDH, PGM and ADH profiles obtained by polyacrylamide gel electrophoresis using conchocelis are thought to be useful for identifying of Porphyra species.

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The effect of reagents related to the non-covalent bonds of proteins, such as alcohols, polyols, and surface active agents, on the dynamic visco-elasticity of suwari gel from jack mackerel was studied. Storage modulus (G') and loss modulus (G'') of the gel increased by the addition of alcohols, such as methanol, ethanol, and n-propanol, but decreased by that of polyols, such as ethylene glycol, glycerol, sorbitol, and sucrose, and surface active agents, such as sodium laurate andsodium dodecylsulfate. With the rise of measuring temperature from 10 to 40°C, the G'and G''decreased in the gel with polyols added, but the decrement was not so large in the gel with surface active agents added. G'and G''slightly increased in the gel with methanol added but decreased in the gel with n-propanol added.

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Klebsiella sp. isolated from water of the Sumida River produced an extracellularpolysaccharide “BS-1”. The BS-1 was prepared by an addition of ethanol to the culture broth containing 3% lactose. It was further purified for chemical analyses. Itshomogeneity was confirmed by both ultracentrifugal and electrophoretic analyses. Color reactions, thin layer chromatography, gas-liquid chromatography, and elementary analysis indicated that the BS-1 was an acidic heteropolysaccaharide composedof galac-tose and glucuronic acid in the molar ratio of 4:1. The order of its molecular weight was estimated to be more than 10⁶ by gel permeation chromatography. Pyruvic acid and acetyl group were not found as structural components. By the comparison of these results with those of the reported polysaccharides produced bysome known strains of Klebsiella, the BS-1 was considered to be a newheteropolysaccha-ride.

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Monoamine oxidase A (EC 1. 4. 3. 4) in skipjack liver was extracted from mitochondrial prepara-tions by Triton X-100. The enzyme was purified by ammonium sulfate fractionation, followed by chro-matographies of Sephadex G-200, Butyl Toyopearl 650M, and hydroxyapatite. By this method a final specific activity of 19.5 units/mg and 30-fold purification were attained.
The molecular weight of the final preparation was estimated to be about 130, 000 by gel filtration on Sephadex G-200. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated asubunit molecular mass of 64, 000. The optimum pH was 9.0 and the enzyme was stable between pH 9.0 and 10.0 after incubation at 4°C for 60 min. The optimum temperature was 30°C. The enzyme was in-hibited by Ca²⁺, Mg²⁺ and Mn²⁺, but was activated by Cu²⁺. Theenzyme showed a high activity by 5-hydroxytryptamine, tyramine and epinephrine assubstrates, but showed low activity by benzylamine and 2-phenylethylamine.

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The effects of microbial transglutaminase (MTGase) on fish muscles of seven kindsof fish-species were studied to increase the basic knowledge of the preparation of the high quality frozen surimi. Be-cause of the full consideration of application, all tested samples were prepared in the surimi plants with the commercial manufacturing process. The textural properties of each surimi gel were measured by apunch force and punch deformation. The condition of setting was defined at 30 C and for 60min. The accuracy of the data of the punch test was investigated by using the coefficient values of variation. The effects of MTGase on surimigel varied with each fish species. The values of the punch force of all tested surimi gelsincreased with the addition of MTGase, but the values of punch deformation decreased with an addition of over 0.03% MTGase in general. Since, the value of the punch deformation is highly ap-praised by Kamaboko makers more than the punch force, about 0.03% of MTGase (1.1 unit/mg pow-der used) were recommended for the desirableconcentration in the frozen surimi processing. However, thereis a recognizabledifferences in the two kinds of walleye pollock surimi. The results show thatthe increasing effect of MTGase is not only controlled by the fish species but also by more complicated fac-tors such as freshness of the raw fish.

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Triglycerides (TGs) from orbital fat of tuna (tuna-TG) and from soybean oil (soy-TG) were dis-persed in a buffer with milk casein and their oxidative stabilities in an emulsion were compared with those in the air. Since the average number of bisallylic positions in tuna-TG molecule was higher than that in soy-TG molecule, tuna-TG was more susceptible to oxidation than soy-TG in the air. However, tuna-TGbecame oxidatively more stable than soy-TG in an emulsion. PV of soy-TG increasedrapidly after 100 h of oxidation in an emulsion, but such an increase was not observe in the oxidation of tuna-TG. Gas chromatographic analysis also showed that 94.0±3.8% of polyunsaturated fatty acids (PU-FAs) in tuna-TG remained unchanged after 240 h of oxidation in an emulsion, while soy-TG was more rapidlyoxidized inan emulsion with loss of 76.2±1.1% of PUFAs after 240 h of oxidation. These resultsshow the possibility that fish oils may be protected from their oxidations by emulsification.

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Common carp Cyprinus carpio were fed at a constant feeding rate for 30 days on isoenergetic diets containing different levels of carbohydrate (4-58%) and protein (65-27%), and activities of several hepatopancreatic enzymes together with growthperformance were determined. Dietary inclusion of adequate levels of carbohydrateimproved the growth and feed conversion and exerted a protein-spar-ing effect. With increasing dietary carbohydrate levels and decreasing protein levels, the activities of hepatopancreatic glucosephosphate isomerase, glucose-6-phosphate and phosphogluconate de-hydrogenases, and malic enzyme as well as hepatopancreatic glycogen and serum triglyceride contents increased, while those of glucose-6-phosphatase, arginase, GOT, and GPT together with serum free amino acid concentrations decreased. Therefore, high correlation coefficients were obtained between dietary carbohydrate levels and these biochemical parameter concentrations. The results suggest that dietary carbohydrate stimulates glycolysis and lipogenesis and depressesgluconeogenesis and amino acid degradation in the hepatopancreas. This comprehensive regulation of nutrient metabolism may ac-count for the protein-sparing effect exerted by dietary carbohydrate.

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A specific and sensitive enzyme-linked immunosorbent assay (ELISA) was developed for the measurement of low levels of serum vitellogenin (VTG) of the Japanese eel Anguilla japonica. The non-competitive avidin-biotm interaction was performed by a sandwich method using the specificity of the specific antiserum to eel yolk protein (a-lipovitellin) and biotinylated F (ab')₂ fragment of a-lipovitellin. The assay could be run in 2 days and routinely detect VTG in a concentration as low as 0.8 ng/ml. The appearance of low levels of serum VTG significantly increased 9-12h after a single injection of estradiol-17β into immature fish.The development of an ELISA for VTG made possible the quantification of serum VTG and thereby in vitro analysis of the mechanism of the onset and course of vitellogenesis.

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Microbial flora of an indigenous food to Japan, fermented puffer fish ovaries, “fugunoko nukazuke”, were examined. Samples used for the examinations were salted ovaries of puffer fish Fugu stictonotum for 2 months and 1 year, exudate from ovaries after 2 months' and 1 year's salting, ovaries fermented in rice-bran for 4 months and 2 years, and rice-bran fermented for 4 months and 2 years.
The viable bacterial counts obtained from these samples were different dependingon the culture conditions and manufacturing process. However, high counts of 10⁷ cfu/g and 10⁷ cfu/ml were obtained in some samples of fermented rice-bran and exudate.
Most isolates which were tolerant to high levels of salt concentration can be tentativelydivided into four groups: lactic acid cocci, halophilic anaerobes, Pseudomonas-like halophiles, and halophilic archaea. These four groups of bacteria were found insalted ovaries and exudate, while in the samples fermented with rice-bran the dominant microflora were lactic acid cocci. Bacillus, Corynebacterium, and Staphylococcus were also isolated, but the counts of these were much lower.

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The very-low-density lipoproteins (VLDL), low-density lipoproteins (LDL) and high-density lipoproteins (HDL) were isolated from the serum of red sea bream by sequential preparative ultracentrifugation and high performance gel-filtration chromatography. The major lipid components of VLDL and LDL were triglycerides; however, thepercentage of sterol esters in LDL was higher than that in VLDL. The HDL contained phospholipids as the major lipid components. Red sea beam apo VLDL and apo LDL contained predominantly apo B-like proteins (150-250 kDa) in addition to small molecular weight proteins(6-7 kDa). Apo A-I-like (27.5 kDa) and apo A-II-like proteins (14 kDa) were the major constituents of apo HDL. The isoelectric points of two major isoforms of apo A-I-like protein (pI 5.4 and 5.3) were similar to thoseof a human counterpart. The molecular weight of apo A-II-like protein was approximately twice as large as that of human apo A-II and the isoelectricpoints of its major isoforms (pI 5.3 and 5.2) were more basic than the major isoform (pI 5.0) of human apo A-II.

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The histopathological effects of a homologous series of amphoteric surfactants, N-alkyl (C₈-C₁₈)-N, N-dimethyl-3-ammonio-1-propane sulfonate, on the gills of common carp Cyprinus carpio were examined by light microscopy. Fish were exposed to the lethal concentration (96-h LC₅₀) of each surfactant for 96 h. The gills exposed to C₈ showed slight hypertrophy of epithelialcells and epithelial lifting of the secondary lamellae. Marked epithelial lifting was observed after the exposure to C₁₀. In the groups exposed to C₁₂, C₁₄, and C₁₆, hyperplasia between thesecondary lamellae occurred to such an extent that it led to lamellar fusion. In the gillsexposed to C₁₈, hyperplasia was more advanced and revealed fusion of the primarylamellae. These findings suggest that the extent of gill damage induced by this homologous series of amphoteric surfactants progressively deteriorated withthe increase in the number of carbon atoms in the alkyl chain.

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A feeding experiment was conducted to examine the effect of several ingredients incorporated in diets as binders on the growth, feed efficiency, and digestive enzymes'activities of fingerling Japanese flounder Paralichthys olivaceus. Carboxymethylcellulose (CMC), gelatinized potato starch (α-starch), and wheat gluten were separately incorporated in flounder diets as binders at the 5% level. These diets were fed to flounder with an initial mean weight of 15g for 4 weeks at 20°C. Weight gain, feed efficiency, and protein retention of the fish fed a diet containing CMC were significantly inferior to those of the fish fed diets containing α-starch or wheat gluten. Apparent digestibility of protein in the diet containing CMC was also significantly lower than the diet containing wheat gluten. Afterthe 4-week feeding trial, proteolitic and lipolitic enzyme activities were measured with the homogenates of stomach or intestine. Proteolitic enzymes' activities such as pepsin-like and trypsin-like were lower in the fish fed the diet containing CMC than those in the fish fed the diets containing α-starch orwheat gluten, and especially trypsin-like activities at 4 to 12 hours after feeding were significantlylower. These results suggest that α-starch and wheat gluten are suitable as binders for fingerling flounder diets compared with CMC because CMC inhibits the proteolitic enzymes' activities in digestive tracts.

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β-Connectin, a 2, 100 kDa fragment of connectin, was extracted with 0.1M phosphate buffer at pH 6.6 and purified on a Bio-Gel A 50m gel filtration from carp skeletal myofibrils. The isolated connectin was in the native state judging from the fact that it enhanced aggregation of both myosin and actin filaments and appreciably elevated actomyosin Mg-ATPase activity.
The thermal denaturation of connectin was measured in 0.1M and 0.6M KCl solutions of neutral pH by means of turbidity. Increase in turbidity was observed at 40°C and occurredmarkedly above 50°C. A physiological concentration of Ca²⁺ and Mg²⁺ did not affect turbidity. Theloss of interaction of connectin with myosin was caused by the denaturation of myosin at lower temperatures rather than that of connectin.

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A marine microalga, Gymnodinium A₃ OKU-1 strain, which was originally isolated from a water sample of the Seto Inland Sea produced an extracellular acidic polysaccharide when grown in a seawater medium. Isolation and purification of this polysaccharide were accomplished by precipitation with ethanol and Cetavlon, followed by fractionation with DEAE-cellulose column chromatography. This polysaccharide preparation, which was homogeneous in both ultracentrifugal and electrophoretic analyses, was composed of galactan containing sulfate and lactate as the components.

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The three-dimensional structure of a collagen fibrillar network was examined by using a cell-maceration/SEM method combined with measuring the breaking strength of rainbow trout, yellowtail, and tiger puffer muscles. Rainbow trout and yellowtail muscles were tenderized during storage, but tiger puffer muscle showed no tenderization even after 72h storage. According to histological observations, the thickness of pericellular connective tissue in rainbow trout and yellowtail muscles became thinner, and the density of their collagenous fibrils decreased during 24h storage. On the other hand, no structural change was observed during 72h storage in tiger puffer muscle. These results showed that the structural change in the collagen fibrillar network corresponded to the post-mortem tenderization. This result agreed well with previous light microscope and transmission electron microscope observations.

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The growth responses of Spirulina platensis NIES-46, a brackishwater strain originally isolated from Lake Texcoco Mexico, to some physico-chemical factors and nutrients were investigated. The optimum conditions for growth were the following: light intensity of 160 μEm^-2 sec^-1, temperature of 30°, pH 10, and chlorinity of 0.55‰. NIES-46 strain could utilize both inorganic and organic phosphorus sources. Values on the different growth parameters for orthophosphate andother organic phosphorus sources were as followings: half-saturation constant of 0.02-0.07mg-P/l; maximum growth rate of 0.8-1.0/d; minimum cell quota of 0.08-0.32 pg-P/cell, and level for saturated growth yield of 0.3-1.0mg-P/l. The result that this species utilized effectively a rather wide range of both inorganic and organic phosphorus and showed a high growth rate suggests that mass production of this species is possible by recycling organic waste.

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A blue carotenoprotein (λ_max=615 nm) was purified and characterized from the exoskeleton of black tiger prawn Penaeus monodon. It contained free astaxanthin as the prosthetic group. Its molecular weight was found to be 126 kDa and 120 kDa by gel filtration and native-polyacrylamide gel electrophoresis (PAGE), respectively. SDS-PAGE indicated that the carotenoprotein consisted of six subunits, with three sets of two kinds of subunits of 22.4 and 21.4 kDa in a molar ratio of 1:1. The stoichiometry of carotenoid and apoprotein was 2:1. Another blue carotenoprotein (λ_max=625 nm) was isolated from the muscular epithelium of P. monodon by collagenase treatment. The molecular weight of the carotenoprotein was determined to be 21.4 kDa by gel filtration. SDS-PAGE indicated that the carotenoprotein was composed of a polypeptide of 22.9 kDa. This carotenoprotein also contained free astaxanthin as the prosthetic group.

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