An echo sounder system attached to an underwater stereo camera system was used to obtain optical and acoustical information on fish. From the photographic data, the species, size, aspect and bearing angles of fish, and the distance between the fish and the transducer were obtained. The effect of transducer directivity was removed from the echo signal by using the bearing angle which is taken to be the same as the directional angle of the fish relative to the acoustical axis. The target strength of the fish was determined from the acoustic data after removal of the effect of aspect angle on the echo signal. Thus, the relationship between the target strength of the fish and its size could be obtained.
These results are thought useful not only for the measurement of the target strength of free-swimming fish, but also for the estimation of fish abundance.

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In this paper, the composition, size and weight of gut contents of some 36, 000 anchovy larvae collected from Suruga Bay from 1968 to 1976 are treated, and the feeding habit in relation to their mode of feeding are discussed.
Anchovy larvae eat infrequently, capture large-sized prey by the “biting lunge” behavior during the day, and are poor feeders. However, for those over 25mmTL., the 3 times increase in the maximum gut content length and the 2.5 times increase in the number of larvae that have the satiety indices of 20.1-40.0% are observed associated with the increase in the growth rates of the mouth and esophagus diameters. Hence, the feeding success of larvae improves with the development of the feeding organs, though their feeding mode is not changed throughout the larval stage. The feeding incidence and gut content weight reach the highest in summer when high water temperatures prevail in their habitat. These do not clearly correspond with the change in the zooplankton concentration in situ.
In summary, it is considered that the food selectivity of anchovy larvae to prefer large sized plankton is a characteristic of the “biting lunge” behavior, and the feeding success will be increased, if concentrated large and seizable food organisms are available to them.

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The Sakasa-ami is a kind of Otoshi-ami (Set net), the entrance of net being open offshore, and the leader net (Kaki-ami) placed in the offshore of the main net. To estimate the fish behavior when they encountered the leader net, the catch by Sakasa-ami was compared with that of the ordinary type of Otoshi-ami, one is Naka-ami and the other is Oki-ami which is located offshore of the Sakasa-ami. A common inshore leader net was placed between Naka-ami and Sakasa-ami. The catch data of Autumn season of 1977 and 1979 were analysed, and the results obtained are summarized as follows:
1) When Tsubaiso Serbia quinqueradiata, young of yellow tail (less than 20cm in body length) encountered the leader net, they showed a tendency to proceed inshore or offshore, while Fukuragi larger type of same species (20-40cm), had a tendency to proceed offshore.
2) Small size of horse mackerel Trachurus japonicus (body length 10cm) showed a tendency to proceed inshore and offshore in the same ratio, but the larger type of same species (15-30 cm) had a tendency to proceed offshore.
3) Barracuda Sphyraena Pinguis seemed to proceed inshore when they encountered the leader net.

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Long-term preservation of Pasteurella piscicida is necessary for producing highly effective bacterins for the control of pseudotuberculosis in cultured yellowtail Seriola quinqueradiata. This report describes the survival and pathogenicity of P. piscicida in stab culture and frozen storage. Strain 5866 virulence was maintained by fish passage. And then both preservation methods were investigated. With stab culture in BHIA, strain 5866 was isolated from every fish passage and stocked at 15°C. For frozen storage, a culture medium composed of polypeptone, yeast extract and NaCl was used. Cultures of strain 5866 were stored in either glycerol (10, 30 and 50% V/V), defibrinated horse blood (10, 30 and 50% V/V), 20% skim milk (10, 30 and 50% V/V), calf or horse serum (50% V/V) or dimethyl sulfoxide (10% V/V) and dispensed in sterile screw-cap vials. The suspensions were stored frozen at -20 and -80°C.
After 3 months, strain 5866 lost virulence when stored in BHIA stab cultures. After 6 months in frozen storage, the relationship between viability and the use of protective additives was not clear. All cultures stored at -20°C showed a gradual decrease in numbers of surviving cells and viability was lost between 1 and 6 months. Cultures stored at -80°C gave a high recovery of viable cells showing the lower temperature was preferable for prolonged storage. Strain 5866 stored at -80°C in skim milk maintained virulence and pathogenicity after 6 months.

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A convenient method for the evaluation of potential antiviral agents against non-segmented negative single strand RNA viruses using infectious hematopoietic necrosis virus (IHNV) in chinook salmon embryo (CHSE-214) cells was performed on microtiter plates with 96 wells. In this system, cytopathic effect (CPE) induced by IHNV infection was detected as clear spots (CPE spot) in CHSE-214 cell monolayers three days after infection. In none of the cases tested, did the standard error for the number of CPE spots per well exceed 10%. This newly developed method was successfully applied to the quantitative evaluation of several antiviral agents against IHNV on microtiter plates (CPE spot reduction method), with a reproducibility equal to the plaque reduction method.

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A radioimmunoassay for cyprinid gonadotropin (GtH) was developed using GtH purified from the silver carp Hypophthalmichthys molitrix and its specific antiserum. The minimum detectable quantity of silver carp GtH was 0.58ng/ml (29pg/tube). The intraassay and the inter-assay coefficients of variation were 6.8% (N=6) and 8.6% (N=5), respectively near 50% binding. This system was found to be suitable for the measurement of plasma GtH of goldfish Carassius auratus and carp Cyprinus carpio and pituitary GtH of some teleosts. The competition curves for goldfish and carp plasma were parallel to the standard curve with silver carp GtH. Pituitary extracts of goldfish, carp, honmoroko Gnathopogon elongatus, medaka Oryzias latipes, and chichibu goby Tridentiger obscurus showed competition curves parallel to the silver carp GtH standard, but plasma and pituitary samples of bitterlings (Cyprinidae) showed less steep curves than the standard. This system was physiologically validated by detecting the ovulatory GtH surge in individual goldfish. Plasma steroid hormone levels during ovulation were also measured and their role were discussed in relation to the GtH surge.

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In order to investigate the effect of handling stressor on blood coagulation, hematological and hemochemical parameters and plasma clotting time were studied in carp Cyprinus carpio (body weight: about 350g). Experimental fish were acclimated to laboratory condition at water temperature ranging from 18°C to 20°C for 50 days before the experimentation. Immediately after the transfer to small tank, fish were stressed by chasing about with the net for two min and recovered for four min. Before, directly after and until 48h following handling, blood samples were collected from the caudal vessels without anesthetization using syringe tipped with 20-gauge needle.
The levels of hematocrit, red blood cell, hemoglobin, serum glucose and serum calcium were increased by handling, but the serum levels of total protein, magnesium, inorganic P and chloride were not affected. Though 3 plasma clotting times: plasma recalcification time, prothrombin time and activated partial thromboplastin time, were reduced rapidly, especially plasma recalcification time was affected most markedly and did not recover within 48h following handling. The decreased plasma clotting times may be due to the response of thrombocytes to increased blood catecholamines by stress.
These results suggest that plasma clotting time, particularly plasma recalcification time. is useful as an indicator of stress.

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The object of the study was to clarify from an ecological point of view that such an inconstant lighting condition which goes on and off with a short cyclic time as the intermittent or flickering light would give a different stimulation from that of a constant light to fish. Horse-mackerel Trachuras japonicus were used soon after being caught by a stationary trap net for a series of experiments, and the observation of the fish school's behavior was continuously carried on for a period of 90 days, during which experimental fish were replaced with new ones everyday. Thus, the total number of fish used for the study amounted to 1, 200.
As a result, it has been confirmed that not only is there a remarkable difference between fish-school behavior in response to inconstant light and that to constant light, but also their behavior varies in great deal with the blinking frequency of the inconstant light.

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The origins and migration routes of migrating juvenile chum salmon Oncorhynchus keta along the Pacific coasts of Hokkaido and Honshu were examined on the basis of seasonal and geographical distribution data. Three groups of migrating juveniles were recognized in the survey area. The first group in the waters from Tsugaru Strait to Hidaka from late May to early June was suggested to originate from the Japan Sea area of northern Honshu or from Mutsu Bay, the second, occurring in large numbers off Hachinohe from mid-June to late June was suggested to be from the Pacific coast of northern Honshu. The third, occurring in large numbers along the Pacific
coast of Hokkaido from early July to mid-July, was estimated to be composed of juveniles from the Pacific coast of Honshu and from nearby localities. The migration routes of the juveniles are considered to be along the coast, and offshore migrating juveniles of various origins are thought to migrate along the Pacific coast of eastern Hokkaido.

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Dried and toasted laver, “Yaki-nori”, Porphyra yezoensis, was compared with dried, but not toasted laver, “Hoshi-nori”, with respect to water sorption and the pigment stability during storage under various conditions.
The water-adsorbing activity of “Yaki-nori” was lower than that of “Hoshi-nori”, and hysteresis effect of the water adsorption profile was observed in “Yaki-nori”, but not in “Hoshinori”. During a three-day storage period at 20°C in 100% relative humidity, chlorophyll a was degraded mainly to chlorophyllide a and pheophorbide a in “Hoshi-nori”, but to pheophytin a in “Yaki-nori”, thus, suggesting that chlorophyllase, which hydrolyzes the chlorophyll and pheophytin to the chlorophyllide and pheophorbide respectively, was inactivated by the toasting process.
During a three-month storage period under various conditions of water activities and temperatures, chlorophyll a and carotenoids were degraded in similar profiles in “Yaki-nori”. However, the rate of pigment degradation in “Yaki-nori” depended more or less on the quality of the sample.

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Effects of various antibiotics on the growth and pigment (violacein) production in eleven strains of Alteromonas luteoviolacea were examined. Antibiotic production by Alteromonas strains was also studied under various conditions. With the lapse of time, actinomycin D, colistin, streptomycin and leucomycin initially inhibited the growth of all the strains, and also their pigment production. Low concentration of chloramphenicol, oleandomycin and erthromycin rather enhanced pigment production in all the strains. Lincomycin, sulfisoxazole and sulfisomezole enhanced their growth, but suppressed their pigment production. When cultured on the ZoBell medium for 24h, the Alteromonas strains produced a compound which inhibited several strains of Vibrio parahaemolyticus, Vibrio alginolyticus, Lactobacillus delbrueckii, Corynebacterium strain 520 and Proteus vulgaris. V. parahaemolyticus and V. alginolyticus were also inhibited by the Alteromonas strains grown on L-valine medium, while Staphylococcus citreus, Micrococcus lysodeikticus, Bacillus subtilis, Escherichia coli and Alteromonas haloplanktis strain 1055-1 were inhibited by the Alteromonas strains grown in a L-tyrosine medium. The optimum pH for antibiotic production was 7. Solid media were found better than broth media for antibiotic production in the Alteromonas strains.

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Effects of glucagon, insulin, and the eel serum on protein, glycogen, and gluconeogenesis in the eel liver cells in primary culture were investigated. The cells cultured in the medium with 0.25μM glucagon for 6 days synthesized glucose and glycogen from ¹⁴C-pyruvate by 37 and 2.5 times higher respectively, than the control cells cultured without glucagon. Furthermore the cells cultured with glucagon incorporated ¹⁴C-leucine into intracellular and extracellular proteins by 1.6 and 1.3 times higher respectively, than the control cells. However, glucagon inhibited glycogen and protein synthesis from ¹⁴C-glucose remarkably.
The cells cultured with 0.25μM insulin for 6 days inhibited gluconeogenesis from ¹⁴C-pyruvate by 30%, but stimulated glycogen synthesis from ¹⁴C-glucose by 2.3 times compared to the control cells.
The cells cultured in the medium containing 10% eel serum (13.5 mg protein/ml) for 5 days incorporated ¹⁴C-pyruvate into glucose by 100 times higher than the cells cultured with NU-serum, which is an artificial serum. Glycogen synthesis from ¹⁴C-pyruvate was stimulated, but that from ¹⁴C-glucose was not stimulated by the cells cultured with the eel serum. These results showed that the effects of the eel serum resembled those of glucagon, and it is suggested that the eel serum contains something like glucagon.

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The salt-insoluble fraction was extracted from the muscle tissue of mature striped dolphins Stenella coeruleoalba, in order to examine the properties of mercury and selenium coexisting in the fraction.
After pronase digestion, almost all of the total mercury and selenium in the salt-insoluble fraction were found in a small amount of insoluble residue, although the protein was nearly dis solved. Most of the total mercury and selenium in the insoluble residue were precipitated by centrifugation after solubilization with 0.1M potassium hydroxide solution. The amounts of total mercury and selenium in the above precipitate were almost the same as those in sodium dodecyl sulfate-insoluble fraction of the muscle.
By treatment with 2-mercaptoethanol, the amounts of mercury and selenium removed from the salt-insoluble fraction were low, and the molar ratio of residual mercury and selenium was approximately 1:1.

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The goal of this study is to obtain a basis for the research of recovering and reutilizing the water soluble proteins discarded into the waste wash waters of the frozen mince (surimi) plants.
Effect of an ultrafiltration system (IHI Co., Ltd.) to recover the water soluble proteins was studied. Proteins from 5 fish species, cod, Alaska pollack, sardine, mackerel, and horse mackerel were studied. The water soluble proteins were extacted with 5-10 volumes of water and the extracts were applied to the ultrafiltration system giving rise to concentrates. The protein concentration of the extracts, 0.1-2%, was raised to 0.4-18% with yields of nearly 90%. The low molecular matters, inorganic and organic, were largely filtered off by a membrane. The molecular weight composition of the water extracts and the concentrates were analyzed by Sephadex G-100 or G-200 gel filtration. The water extracts consisted of 5-7 groups with molecular weight ranging 4, 000-150, 000 and the proteins higher than 10, 000 were recovered in the concentrates by ultrafiltration with sieve size 20, 000. Some packing effect on the sieve was suggested. These profiles were generally found for the five species tested. The applicability of the ultrafiltration system appeared optimistic.

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As a result of screening for antioxygenic principles in marine algae, the effects of two types of red algae, Polysiphonia urceolata and Gelidium divaricatum, were found to be clearly superior to those of brown algae.
Bromophenols with 5-bromo-3, 4-dihydroxy benzaldehyde (I) as the main constituent were identified as the effective principles in P. urceolata.
Two types of bromophenols found in P. urceolata, (I) and 5-bromo-3, 4-dihydroxy benzylalcohol, were synthesized and their antioxidant activities compared with several natural and synthetic antioxidants by the following methods: (1) the oven test, (2) oxygen absorption in emulsion, (3) the Active Oxygen Method, (4) the chemiluminescence method. Both of the bromophenols showed considerable antioxidant activity in these tests at low temperature, however, their effects at higher temperatures were poor.

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Dimethyl sulfide (DMS) and dimethyl-β-propiothetin (DMPT) contents in 20 species of phaeophyta 24 samples, 6 species of rhodophyta and 4 species of chlorophyta were determined by gas-liquid chromatography.
The result, DMS and DMPT were detected in all samples examined; and many kinds of chlorophyta generally contained larger amount of DMS and DMPT than the samples of phaeophyta and rhodophyta.
DMS content in extracts of sea algae increased by incubation at 25°C for 2h. But as this phenomenon was not observed in heated samples, it seemed the formation of DMS was concerned with enzymatic action. The partial purification of this enzyme, extracted from Botan-aosa Ulva conglobata was done by using Sephadex G-200 gelfiltration and DEAE-Sephadex•A 25 column chromatography. The highest activity of the partially purified enzyme thus obtained was observed at 40°C and pH 7.0-7.5.
S-methyl-methionin sulfonium salt as another precursor of DMS was identified in Botan-aosa, but the amount was very little.

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The crude venom (protein concentration 9640μg/ml) was extracted with buffered saline from the spines of the crown-of-thorns starfish Acanthaster planci and assayed for some biological activities. The venom was lethal to mice when administered intraperitoneally and the LD₅₀ was determined to be 2.7mg/kg. In addition to the hemolytic activity against animal erythrocytes in the absence of lecithin, much higher activity was observed in the presence of lecithin, suggesting that the venom contains both direct hemolytic factor(s) and indirect hemolytic factor(s) (phospholipase A). The edema-forming, capillary permeability-increasing and hemorrhagic activities were all positive; the venom dose causing a 130% of the edema ratio in mouse foot, this causing a 10-mm blue spot in rat skin and this again causing a 10-mm hemorrhagic spot, were 9.0, 5.3 and 120μg, respectively. Moreover, histological observations showed qualitatively that the venon induced severe necrosis in mouse skeletal muscle.

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The object of this study is to estimate objectively the species difference and the changes in he physical properties of fish meat during the post-harvest storage and to search for the changes of the muscular matters underlying the property changes. Muscles of five fish species: skipjack, flyingfish, common horse mackerel, plaice, and channel rock fish were stored at 4°C for 14 days. Sample fish were taken out in turn and submitted to measurements of physical properties, namely penetration of a needle, firmness and cohesiveness by a General Foods type Texturometer, respectively. The measured values of each measurement item varied from species to species. During the storage, each of them shifted to the values reflecting the softening of the muscle usually observed. The rate of softening varied from species to species. The extractability of myofibrillar-, sarcoplasmic-, alkali-soluble-, and stroma-protein fractions of five fish muscles did not show any significant changes during storage. The SDS-polyacrylamide gel electrophoretic patterns of these extracted protein fractions and of the myofibrillar proteins extracted after M. H. STROMER showed no difference with respect to the storage time. The muscle samples were broken by rotating blades and sieved by 7 mesh, the percentage of the pieces remaining on the sieve decreased with the decrease of the freshness. The muscle samples were homogenized and the length of the myofibril fragments or the sarcomere number of each fragment was estimated under a microscope. The percentage of the small myofibrils varied by the fish species, and the degree of fragmentation increased with the storage period. These results denoted that changes in the physical properties, namely softening of meat, during the post harvest storage were affected more by the changes of the muscle tissue structures than by the changes of the component proteins.

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Crude stromata were prepared as the residual fraction of salt-extraction of muscles from carp Cyprinus carpio and Japanese mackerel Scomber japonicas. They were divided into alkali-soluble (AL-S, 0.1N NaOH-or 0.01N NaOH-soluble), acid-soluble (AC-S, 0.5M acetic acid-soluble), autocleave-extractable (AU-E, extraction at 120°C for 2h), and residual (RES) fractions.
Constituent proteins in each fraction were examined by the analyses of amino acid and SDS-polyacrylamide gel electrophoresis. It was found in both species that AL-S consisted mainly of denatured myofibril proteins, and AC-S and AU-E mainly of collagen. In both species, the amino acid composition of RES was also found to be similar to connection.

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The rate of non-enzymatic browning reaction taken place during thermal processing of canned sardine was determined. Losses of glucose and G6P in the meat and liquid portions of canned sardine during thermal processing were found to follow first-order kinetics. The loss rate of G6P was greater than that of glucose. Losses of glucose and G6P in meats were larger than those in liquids. However, the activation energies for these losses were approximately 20kcal/mol for both meat and liquid portions. The available lysine degraded at a slightly slower rate, but its activation energy was also equivalent to those for glucose and G6P losses. The development of brown color in liquids of canned sardine increased with the increase in processing time by a first-order reaction (activation energy= 18.8kcal/mol). On the other hand, browning was not visually detected in the meat portion. It was found that canned sardine meats softened with the processing time at every temperature employed in this study (activation energy=35.0kcal/mol).

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The skin of toxic puffers (Fugu niphobles, F. vermicularis vermicularis and F. pardalis) was found to release 5-80MU of tetrodotoxin (TTX) per specimen when lightly stimulated by handling. The puffer did not release any more toxin when the handling stimuli were repeated 3-5 times at a 30 min-interval. Some of them, however, recovered to release TTX on handling stimulus when kept intact for two weeks. The cultured puffer (F. rubripes rubripes) specimens which were artificially toxified by feeding with toxic puffer livers, released TTX up to 540 MU on a single handling stimulus.
From these and other results, it was strongly suggested that TTX acts as a biological defense agent in puffers.

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Contents of free amino acids (FAA) and related compounds were examined in plasma, whole blood, and erythrocytes of four species of freshwater fishes: carp Cyprinus carpio, coho salmon Oncorhynchus kisutch, rainbow trout Salmo gairdnerii, and channel catfish Ictalurus punctatus. The content of each FAA in the erythrocytes washed with saline was always low in all species and about 20-60% of the calculated erythrocytes (CE) content which was estimated from the whole blood and the plasma content. This result probably indicates that FAA in the erythrocytes of fishes were washed out by rinsing. In carp, coho salmon, and rainbow trout, the total amounts of essential FAA in the CE were similar or slightly higher than those found in the plasma, while the total amounts of nonessential FAA in the CE were two to three-fold higher than those found in the plasma. In channel catfish, however, both total amounts of essential and nonessential FAA in the plasma were about one-fifth of those in the CE. The CE levels of phosphoserine, taurine, aspartate, glutamate, and ammonia were 7-30 times higher than the plasma levels. On a percentage distribution basis, the plasma contents of these compounds were only 4-16% of those in the whole blood.

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The effect of washing on the refrigeration tolerance of minced meat from seven species of fish was determined by assaying the kamaboko-forming ability and protein extractability. The quality deterioration occurred at both the freezing stage and the storage period. The degree of the stability of unwashed mince during freezing did not always correspond with that of the stability during storage. In the cases of lizard fish and common mackerel mince the freezing stability was very high, but the storage tolerance was low. In case of carp the case was reverse. Horse mackerel, red branchiostegus fish and flat-nosed shark minces were very stable to both freezing and storage, while Alaska pollack mince was extraordinarily unstable to both. When minces were washed, their stability to freezing were remarkably lowered, while their storage tolerance were increased, although the extent of the increase was different with the fish species and storage period. The addition of sucrose to washed mince was very effective in increasing the freezing stability, but not so effective in enhancing the storage tolerance. From these results it became clear that “washing” in the frozen surimi making process is for improving the storage tolerance of fish meat and “sugar adding” is for recovering a loss of the freezing stability suffered during “washing”.

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Cobalt-binding substances in the branchial heart of Octopus vulgaris were examined by means of gel-filtration, ion-exchange chromatography, electrophoresis and amino acid analysis.
Two cobalt-binding substances were fractionated in the gel-filtration experiment. Their molecular weights were estimated to be 2000 and 1000 and they developed reddish brown and pale yellow colors, respectively. They showed, almost the same amino acid composition; namely, both showed a characteristic feature of predominant Gly. Next to Gly, Asp was obviously observed as compared with other trace amounts of amino acids.
By considering their molecular weights, amino acid composition and other results of the experiments, the cobalt-binding substances were estimated to be adenochromes, purple-brown pigments, in the branchial heart.

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