As part of on-going efforts to reduce environmental phosphorus (P) and nitrogen (N) loading from culture systems, five experimental diets were formulated containing 5-15% of fish meal (FM) and different levels of soy protein concentrate (10-20%), corn gluten meal (3-5%) and defatted soybean meal (2.0-8.5%). These diets had total P ranging between 1.04 and 1.29% and available P between 0.62 and 0.63%. A FM-based (43%) commercial diet was used as the controland this diet had total P of 1.87% and available P of 0.82%. Waste loading was calculated after feeding the diets to 3.4 g carp for 10 weeks. Feed gain ratios were not significantly different for fish fed control and experimental diets having 10-15% FM, but the protein efficiency ratio was lower for the control group. The rates of P absorption and retention in the experimental dietgroups were significantly higher than those of the control group. The lowest N retention was obtained for the control group, although absorption was not markedly different among the treatment groups. Total P and N loading (kg/ton production) produced from the experimental diets ranged from 7.1 to 8.9 and from 36.1 to 41.3, respectively, whereas the corresponding values for the control dietwere 15.2 and 48.1.

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Through a series of experiments, it has been demonstrated successfully that an appropriate choice of ingredients is primary for achieving a reduction in phosphorus (P) and nitrogen (N) loading from carp culture. In this final study, four multi-ingredient diets were examined. In addition to the basal ingredients (fish meal 15%, corn gluten meal 8%, defatted soybean meal 10%, blood meal 3-5%), three of the test diets (PF, MM, and SP) contained 6% each of either poultry feather meal, meat meal or soy protein concentrate, respectively, and the fourth diet (PMS) had each of the three aforementioned ingredients includedat 3%. These diets had crude protein <35%, digestible energy >3.5 kcal/g, available P between 0.65 and 0.66% and total P ranging from 1.26 to 1.36%. The diets were fed to juvenile carp during a 12-week feeding trial. The highest growth was obtained for fish fed the MM diet. The absorption and retention rates of P were higher for the PF diet, whereas these values for N did not showtreatment-related differences. The total discharges per ton fish production were estimated to range between 7.8 and 9.2 kg for P and between 39.1 and 40.7 kg for N. These were lower than the figures for Lake Kasumigaura, a main carp culture site, indicating that proper balancing of protein ingredients aids in efficiently lowering emissions from aquaculture.

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The in vitro effects of 17, 20β-dihydroxy-4-pregnen-3-one (DHP) and prostaglandins (PGE₁, PGE₂, PGF_1α, PGF_2α) on ovulation in the Japanese eel Anguilla japonica were examined. Oocytes with follicle layers at the migratory nucleus stage (approximately 850-900 μm diameter) were removed using a polyethylene cannula from artificially matured fish. At concentrations of 10 and 100 ng/mL, DHP was found to induce both germinal vesicle breakdown and ovulation. The prostaglandins, except for PGE₁, effectively inducedovulation of previously matured oocytes by DHP treatment in vitro. Prostaglandin F_2α was the most effective. A significant increase in ovulation rate was observed even at a concentration of 0.01 μg/mL PGF_2α. Indomethacin blocked the in vitro ovulation induced by DHPand addition of PGF_2α reversed indomethacin-blocked ovulation. Actinomycin D and cycloheximide blocked DHP-induced ovulation and PGF_2α reversed the effects of both inhibitors. These results indicate that DHP induces ovulation through endogenous prostaglandin synthesis in the follicle layers of the Japanese eel.

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Three diets supplemented with taurine, β-alanine and GABA and a control diet were fed to juvenile and fingerling Japanese flounder to investigate the effects of the diets on growth and metabolic changes of free amino acids in whole body and tissues. In experiment I, three diets supplemented with 1% each of taurine, β-alanine and GABA and a control diet were fed to juvenile Japanese flounder with an initial mean body weight of 0.4 g for 4 weeks at20°C. In experiment II, the taurine-supplemented diet and a control diet were fed to fingerling Japanese flounder with an initial mean body weight of 15 g for 4 weeks at 20°C. Only supplementation of taurine in the diet of juvenile flounder improved their growth performance in experiment I, but fingerling growth performance of experiment II was not significantly related to taurine supplementation in the experimental diet. These results suggest that there is a greater requirement for taurine for the growth of juvenile Japanese flounder than fingerling Japanese flounder.

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Life history parameters (growth pattern, the length of the spawning season and age at sexual maturity) of Apogon lineatus were investigated from three localities in Japan. The maximum ages were found to be 3 years in Tokyo Bay, 2 years in Osaka Bay and 5 years off Niigata Prefecture. Both sexes from Tokyo Bay grew to larger sizes between the ages of 1 and 2 years than both sexes from otherlocalities, food availability being suggested as the major factor for differences in growth. Spawning seasons were during 4 months (July-October) in Tokyo Bay and Osaka Bay, but were found to only occur during the two months of July and August off Niigata Prefecture. Factors that could limit the spawning season off Niigata Prefecture were not determined. Age at maturity for both sexes inall localities appeared to be 1 year. We could not elucidate whether these variations in life history parameters arose from genetic differences or from phenotypic plasticity. In either case, the trade-off between the maximum age and the length of the spawning season in the off Niigata Prefecture population and any other population may be interpreted as an adaptation to local conditions, such as with the off Niigata Prefecture population.

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We collected phytal animals (fauna associated with drifting seaweeds) off the Tohoku coast in northern Japan in May and June 1994 to examine their feeding habits. Phytal animals were assignedto the following three feeding habit groups: (i) carnivores preying on crustaceans: a gammarid (Stenothoe sp.) and a decapod megalops; (ii) omnivores feeding on crustaceans and pinnate diatoms: a cirripede (Lepas anserifera), three gammarids (Calliopius sp., Jassa slatteryi and J. marmorata), an isopod (Idotea metallica), a decapod crustacean (Planes cyaneus), a decapod megalopsand two caprellids (Caprella penantis and Caprella mutica); and (iii) herbivores grazing on pinnate diatoms, fucoids and seaweeds other than fucoids: three gammarids (Allorchestes angusta, Amphithoe lacertosa and Perampithoe lindbergi), an isopod (Cymodoce japonica) and a polychaete (Platynereis bicanaliculata). Pinnate diatoms in the gut contents were composed mainly of Licmophora spp., Navicula spp., Nitzschia spp. and Cocconeis spp. and seaweeds other than fucoids (i.e. Ectocarpus siliculosus and Sphacelaria furcigera). The latter twoalgae seemed to be epiphytes on drifting seaweeds. These results suggest that phytal animals play an important role in drifting seaweed communities through trophic linkage with two primary producers (i.e. drifting seaweeds and the epiphytes growing on them).

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We examined the diets of three size groups of the Pacific pomfret Brama japonica collected in April and May 2000 in the transition zone of the central North Pacific. Amphipods, cephalopods and fish werethree of the most common prey groups of pomfret. Of the three size groups, small pomfret (11.0-19.9 cm standard length (SL)) preyed mainly on amphipods and occasionally on cephalopods (mainly transitional species Onychoteuthis borealijaponica) and fish.(These prey amphipods and fish could not be identified to lower taxonomic levels because they were too digested.) Medium and large pomfret (20.0-30.9 and 31.0-40.9 cm SL, respectively) preyed mainly on cephalopods (mainly O. borealijaponica, but also on two subarctic species, namely Berryteuthis anonychus and Gonatopsis borealis), suggesting that these cephalopod species ensure energy for the northward migration of these two size groups in the transition zone in the spring. The next most common prey for medium pomfretwas amphipods (mainly subtropical species Phronima sedentaria and Platyscelus ovoides), followed by fish (mainly Bathylagus sp.). However, in the case of large pomfret, fish (mainly Paralepididae sp. ‘A’) were the next most common prey, followed by amphipods (mainly P. sedentaria and P. ovoides), indicating that the importance of fish as prey increases with growth for medium and large pomfret.

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The effects of lunar phase and habitat depth on the vertical migration patterns of the sergestid shrimp Acetes intermedius were examined based on seven field observations in coastal waters off south-western Taiwan. The results indicate that the pattern of nocturnal vertical movement of A. intermedius depends on the lunar phase. The shrimp evaded moonlight during the ascending period andthen the moon was used as a trigger for resuming an ascent towards the sea surface or descending towards the 10 m water layer. During the descending period, A. intermedius moved rapidly to the bottom or to a middle water depth at 50-80 m before sunrise. However, A. intermedius in waters of deep Kaoping Canyon can also perform a slow descending migration thatcoincides with photosynthetically active radiation of 4 μmol/s per m². Because the density of A. intermedius on the surface layer is affected by moonlight, the lunar phase is one of the factors affecting the catch rate of large-skimming nets during the night in waters off south-western Taiwan.

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We have been developing an artificial bait for longline tuna fishing using the liver of the Japanese common squid Todarodes pacificus, a waste product of the squid fisheries industry, as the primary component. Three control test operations using the artificial bait and natural squid were conducted during January 1998, 1999 and 2000. During these operations, we compared the angling performance of the artificial bait with that of the natural squid. Some tuna was caught using the artificial bait; however, the hooking ratio for the artificial bait was less than that for the natural baits. Despite this, there was no significant difference between the hooking ratio by artificial bait and natural squid. In addition, species selectivity in the by-catch, a characteristic particular to this artificial bait, was observed. In the present paper, we discuss the hooking ratio and the reduction in by-catch of the artificial bait compared with natural bait.

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Elasmobranch fish, particularly deep-sea sharks, are the most important component of the by-catch of the hake semipelagic near-bottom ‘pedra-e-bola’ longline fishery in the Algarve (South Portugal) and most of these fish are discarded. The effects of the removal of the lower hooks were evaluated, in terms of target and by-catch reductions, by quantifying the catches of each hook relative to the distance from the bottom. The analysis showed that most European hake (Merluccius merluccius), the target species of this fishery, were caught in the middle range of the hooks, with very few individuals caught near the bottom, whereas for sharks the situation was the opposite, with most hooked near the bottom. The removal of the lower three pairs of hooks wouldresult in a small reduction in the catch of the target species, but a much more significant reduction in elasmobranch by-catch. In the specific case of the blackmouth catshark (Galeus melastomus), discard mortality would be further minimized due to the fact that the lower hooks capture significantly smaller animals that are always discarded compared with hooks that are more distant from the bottom.

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A mooring-type underwater positioning system (UPS) to measure the bag-net movements in a set-net by acoustic telemetry techniques with five transponders was reconstructed. The field experiments were conducted in Jaran Bay, Kosung, Korea on 6 October 2000 (neap tide) and 28 November 2000 (spring tide). The average UPS fixing errors of x-axis, y-axis and z-axis were less than 0.6 m, 0.8 m and 1.2 m, respectively. The longitudinal movement range, the latitudinal range and the vertical range of the bag-net at the neap tide were 3.2 m, 3.4 m and 2.1 m, respectively. At the spring tide, these ranges were 7.8 m, 7.8 m and 5.0 m, respectively. It was confirmed that the UPS system could be used for measuringa part of the bag-net movement.

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A physical model of a soft shell underwater float with an open bottom was constructed and the float was subjected to sinusoidal oscillation in the vertical direction in order to investigate the relations between the characteristic properties of the buoyancy and fluid forces in the movement of the float. No change in the fundamental period of the float was seen in response to the imposed oscillation, but there was a lag in the phase of the float response of up toone-quarter wavelength. Various fluid force factors approached values reported for a globular buoy as the float was increasingly filled with air, but hysteresis was very low. The drag coefficient showed much scatter. The dominant factor for control of vertical movement of a soft shell float with open bottom was buoyancy, not fluid resistance force. It was concluded that for the purposes of design and control of these systems, only the float volumetric capacity and air capacity must be considered.

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The red drum Sciaenops ocellatus Linnaeus is an exotic aquaculture species in Taiwan. As a carnivore it preys on a variety of food organisms, including fishes and invertebrates. Isolating the sensory mechanisms that govern its predatory behavior would help clarify its feeding habit. The present study focused on predation responses influenced by vision, olfaction and lateral line in captive juvenile red drum. Results showed that the lateral line had themost significant influence on predatory behavior of the fish. Blocking mechanoreception of the lateral line system resulted in complete loss of ability to catch prey. Ablation of olfaction, in contrast, caused a booster effect on the predation rate. Experimental fish with scorched olfactory rosettes showed active predatory behavior. Nearor complete darkness had insignificant influence on the predation rate. When the lateral line system was blocked, the fish could not prey normally, even when vision and olfaction were left intact. It was concluded that mechanoreception plays the primary role and vision the secondary role in predatory behavior of the red drum.

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The development of embryos, larvae and juveniles of the Ryukyu-ayu, Plecoglossus altivelis ryukyuensis are described based on laboratory-reared specimens. The eggs were spherical, 0.98-1.18 mm (mean 1.06 mm) in diameter with an adherent membrane. The incubation period after fertilization was approximately 155 h at a water temperature of 19.7-22.0°C (mean 20.7°C). Newly hatched larvae were 5.0-5.9 mm (mean 5.5 mm) in body length (BL) with 59-62 myotomes. Within 5 days after hatching, the larvae had attained 6.4-8.2 mm (mean 7.8 mm) BL and had completely consumed their yolk. Notochord flexion began at 13.7 mm BL and was completed by 16.3 mm BL. The rudimental dorsal, anal, pelvic andadipose fins appeared at 14.7, 16.3, 21.8 and 21.8 mm BL, respectively. All fin rays reached the same fixed number of adult fish at about 28 mm BL. The comb-like teeth began to form at approximately 30 mm BL and were fully developed at about 40-50 mm BL. The proportions of P. a. ryukyuensis specimens, which were consistent with adult fish, occurred at approximately 40 mm BL.

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The influence of reward level on vertical distribution and growth was examined in rainbow trout fed on demand with self-feeders. Groups of 15 trout with initial body weight of 140 g were maintained at 14°C and feed access was restricted to a 12-h photophase. The trout received three reward levels with triplicates: 0.051 (low), 0.089 (medium) and 0.267 g/kg fish/trigger actuation (high). Vertical distribution in the higher reward groups was generally more even than that in the lower-reward groups, but the behavioral characteristics of some individuals in a group could play an important role in determining vertical distribution. Moreover, no fish including the individuals responsible for trigger actuation, occupied the vicinity of a trigger. The small groups of 15 trout receiving the medium-reward level obtained as much feed and grewas fast as the high-reward groups, but this was not the case for the low-reward groups.

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The parasite fauna of Mustelus manazo from seven localities in Japan and Taiwan was assessed for the feasibility of using parasitesas biological tags for the identification of different host stocks. Examination of 1038 host specimens resulted in 13 parasite species recorded: one nematode, two myxosporeans, two copepods and eight cestodes. Although relatively low overall prevalence of the first five species at different localities showed some significant differences, the samples collected in Tokyo Bay bore the lowest similarity (19.2%). These results support previous studies, which suggested the existence of a unique host stock in Tokyo Bay. Accordingly, combinations of prevalence data may provide useful information on stock identification. Cestodes probably have the greatest potential for use as biological tags. Detailed examination of 25 specimens of M. manazo from Aomori and Tokyo Bay disclosed eight species of intestinal cestodes. A canonical discriminant analysis based on these species separated the two localities clearly.

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The appropriate water velocity in artificial burrows for the Japanese crayfish species Cambaroides japonicus was studied. An experimental system of two artificial burrows (burrows A and B) of the same size was set in a large tank. The velocity of burrow A was 0 cm/s and that of burrow B was varied andset at 0 cm/s, 5 cm/s, 10 cm/s, 20 cm/s and 30 cm/s. The selection of these two burrows by C. japonicus was observed. No animals selected burrow B significantly more than burrow A above 10 cm/s. At 20 cm/s, some crayfishes were swept away and could not return to burrows because of the high water velocity. At 30 cm/s, most animals were swept away. We conclude that the appropriate water velocity for the suitability of artificial burrows and the immediate foraging area adjacent to the burrows should be as low as 5 cm/s.

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The auditory characteristics of pelagic fish have received less attention compared to those of benthic or freshwater fish species, even though underwater sounds are considered to affect their behavior. Audiograms of five spotlined sardines were obtained using the auditory brainstem response technique in which the evoked potential on the skin covering the head of the fish was measured. The auditory brainstem response is a non-invasive electrophysiological method that enables the auditory threshold level of fragile species, such as spotlinedsardines, to be measured. The gas bladder of the spotlined sardine has been considered as possibly contributing to an enhancement in their hearing. In the test, the sound absorption profile of sardines was also measured. The frequency at the lowest auditory threshold level (i.e. the most sensitive frequency) and absorption were foundat 1024 Hz and 1040 Hz, respectively. The spotlined sardine was found to be sensitive to sounds at relatively higher frequency ranges compared to other seawater fishes and the gas bladder is seen to play a significant role in detecting sound.

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To elucidate the recruitment and movement process of larval ayu in the surf zone of a sandy beach facing Tosa Bay, 31 collections were made with a small seine net at intervals of approximately 5 days from November 1990 to April 1991. On the basis of seasonal variations in larval abundance, size, age, duration of residence, and the occurrence patterns of ayu in the surf zone, larval ayuwere classified into two groups: short-term resident (<30 days in duration) and long-term resident (90-120 days). The former appeared in the surf zone abundantly from mid-November to mid-December and resided there for about 1 month until they reached approximately 25 mm BL. It is likely that larval ayu (short-term resident), which recruit abundantly to the surf zone, expand their distribution offshore at approximately 25 mm BL. In contrast, the latter group were found after mid-December, and the population size was markedly small although they stayed continuously in the surf zone for 3-4 months until they reached approximately 40 mm BL.

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Genetic variation of the fungal parasite Pythium porphyrae, causative organism of red rot disease of Porphyra, isolated from Asan, Mokpo, Pusan and Wando in Korea, and from Aichi, Fukuoka and Miyagi in Japan was investigated by random amplified polymorphic DNA (RAPD) cluster analysis. The total 67 RAPD markers were generated from 38 isolates by RAPD-polymerase chain reaction (PCR) using arbitrary primers consisting of 10 nucleotide sequences and 33 of them indicated polymorphisms. The dissimilarity coefficients calculated from the RAPD banding patterns ranged from 0.0010 to 0.6983. The dendrogram generated by the unweighted pair-group method using arithmetic averages showed that the 38 isolates were classified into three clusters (Groups 1, 2 and 3). Group 1 consisting of two isolates from Miyagi was separated from all other isolates by a genetic distance of 0.6983. Groups 2 and 3 containing the majority of the isolates were branchedon genetic distance of 0.3957. These two clusters subdivided into four and three subclusters, respectively, which were apparently associated with geographic origins of the isolates. Interestingly, the isolates from Asan of Korea were close to Japanese isolatesrather than Korean isolates on genetic diversity. In addition, thegenetic distances of intra-isolates from Japan were higher than those from Korea.

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Bioaccumulation and distribution of Mn and Zn in the total soft tissues, digestive glands, residuals and adductor muscles of the horse mussel Modiolus modiolus from three sites, including industrialized and non-industrialized locations in Eastern Canada, were investigated. Extremely high digestive gland metal concentrations were found in individual mussels, as high as 1819 μg/g Mn wet weight and 1964 μg/g Zn wet weight, with mean values from 358 to 404 μg/g Mn and from 399 to 614 μg/g Zn for the collection sites. High Mn to Zn interrelationships were observed inall types of tissues and at all sites. Between different tissues, Zn was interrelated by linear relationships, and Mn was best described by power curve relationships for all tissue types. In the total soft tissue, Mn and Zn interrelations were fitted to power regression curves with different slopes between the three study sites. This indicated that horse mussel was exposed to different metal levels inthe environments and could be useful for monitoring these metals. The uptake of both metals at extremely high concentrations, the lack of regulation and the occurrence of interactions all suggest that Mn and Zn may play a biological role in horse mussels. Zn and Mn interactions, surprisingly, were not disrupted at the very high concentrations of either metal, which proves that the mechanism of metal interactions does not involve a detoxification role.

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inhibitory effect of 70% acetone extract of enokitake mushroom Flammulina velutipes on the mealnosis of shrimp Trachypenaeus curvirostris was investigated. The acetone extract effectively prevented the mushroom tyrosinase activity as well as melanosis of American crayfish Procambarus clarkii hemolymph. When each of two fractions of the acetone extract, which were unadsorbed on both of Dowex 50W X8 and/or DEAE-TOYOPERAL 650 columns, was mixed with hemolymph of the American crayfish, the melanosis that usually occurs in the heparinized hemolymph was effectively prevented. Immersing shrimp in the acetone extract of enokitake mushroom delayed the color darkening usually found in the post-mortem shrimp. These observations suggested that enokitake mushroom contained certain compounds that inhibit the formation of melanin due to the catalytic oxidation of polyphenol oxidase, as well as mushroom tyrosinase activity.

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A rapid clustering scheme for Vibrio species was developed based on the analysis of 16S rDNA, which compriseda group-specific polymerase chain reaction (PCR) and restriction fragment length polymorphisms (RFLP) of the PCR-amplified 16S rDNA. The group-specific PCR, using a specific primer Vib1F, clustered the Vibrio species into two large groups: Vib1F⁺ group and Vib1F^- group. The PCR-RFLP, using ScaI and BlnI, further divided these groups into smaller groups. Finally, 46 Vibrio species and eight related species could be clustered into 14 groups usingthis rapid clustering method. Seasonal dynamics of the Vibrio community in Yoshimi Bay, Hibiki-nada Sea, Japan, were examined based on the rapid clustering method. In both seawater and sediments, the group comprised Vibrio parahaemolyticus, Vibrio alginolyticus, Vibrio campbellii, Vibrio carchariae, Vibrio harveyi and Vibrio natriegens and was predominant when the seawater temperature was above 20°C, whereas the group of Vibrio splendidus biotype I and Vibrio lentus was abundant when the temperature was around or below 20°C.

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In order to identify free amino acids (FAA) that are important as intracellular osmolytes in Crassostrea gigas, we investigated the change in FAA content in the mantle exposed to an abrupt decrease or increase in salinity. In hypo-osmotic adaptation, most FAA showed remarkable and synchronous decreases from 2 to 8 h, suggesting that the non-selective efflux of FAA was mainly responsible for the decrease in FAA. Taurine that accounted for approximately 80% oftotal FAA content contributed most significantly to the hypo-osmotic adaptation. In hyper-osmotic adaptation, significant increases in glycine, alanine, β-alanine, proline, arginine and taurine were observed. Of these, alanine showed an immediate increase that is important to short-term adaptation to hyper-osmolality, while taurine showed a slower and substantial increase that contributes to a long-term adaptation to hyper-osmolality.

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The skin of halibut Reinhararditus hippoglossoides has been discarded as a waste product in large quantities by the food industry; hence, we examined the biological activity in the skin in order to make good use of the waste. In the present study, we determined induction of hepatocyte growth factor (HGF) from the MRC-5 human fibroblast cells and inhibition of cell proliferation in tumor cells using various components extracted from the fish skin. The glycosaminoglycan fraction was extracted with alkali solution and fractionated byion chromatography. Consequently, dermatan sulfate showed the strongest activity in HGF induction, as well as commercially available heparin and heparan sulfate. Moreover, the alkali extract of fish skin showed inhibition of proliferation for some tumor cells in vitro. In particular, viable cells determined by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-tetrazolium bromide (MTT) assay were significantly decreased by 5% in HL60 and 8% in U937 of leukemia cells in the medium containing 5 mg/mL alkali extract. These observations indicate that the fish skin has significant biological activity and is valuable for functional foods and drugs.

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Change in the translucency of squid mantle muscle during its storage at 0°C was studied by monitoring L* valueand turbidity. Two indicators showed that squid mantle muscle lostits translucency and reached maximal turbidity within 24 h of storage. Thickness of mantle muscle also increased by 15% in 12 h, earlier than the loss of translucency. ATP content decreased with storage time and was completely lost in almost 24 h, a similar period to translucency loss, but later than rigor contraction. Development of black color on skin surface by chromatophores was fully achieved in 24 h. It was thus concluded that ATP content was well correlated with a loss of translucency or increase in the turbidity of mantle muscle and development of dark coloron the surface skin of mantle.

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Purified trimethylamine-N-oxide demethylase (TMAOase) from walleye pollack muscle is a thermostable protein that was not inactivated after heating at 80°C for 30 min. The heated enzyme was electrophoresed in the same manner as fornative enzyme. Circular dichroism (CD) spectra for purified enzyme changed reversibly in the temperature range of 10-80°C. As the enzyme was still active at 80°C, the CD spectral change did not directly relate to enzyme activity. TMAOase activity inthe myofibrillar fraction decreased sharply above 30°C, but was extracted and recovered from the heated myofibrillar fraction, suggesting that the activity seemed to be interrupted and apparently inactivated due to the thermal alteration of myofibrillar proteins or some unknownfactors. The complicated profile found in dimethylamine (DMA) formation from trimethylamine-N-oxide (TMAO) in walleye pollack muscle during heating consisted of both enzymic and non-enzymic processes. Most DMA was produced enzymatically below 40°C and interrupted above 40°C. Therefore, DMA and trimethylamine was formednon-enzymatically at high temperatures regardless of the presence of native enzyme. A new, simple and easy purification method was proposed based on the thermostable nature of the enzyme.

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