Optimum conditions of ultraviolet (UV) ray irradiation for genetic inactivation of eggs were examined to develop simple and easy techniques to induce androgenesis in the loach, Misgurnus anguillicaudatus, since ionizing radiation such as gamma-or X-ray, which has been used generally for fish androgenesis, gives technical problems of safety and the need for special facilities. In the first and second experiments, unfertilized eggs were exposed to UV rays from two sources, germicidal lamps affixed to the ceiling and below, at dosages from 1875 to 15000 erg/mm2. While in the third experiment, eggs being shaken in a micro mixer were irradiated with UV rays from ceiling lamps at dosages between 4200 and 21000 erg/mm2. Most embryos developing after fertilization with normal spermatozoa showed abnormal morphology and a haploid number of chromosomes (n=25) in all the experiments, indicating successful induction of androgenesis. Occurrence of some aneuploids and diploids suggests the necessity of further improvement for homogeneity of treatment.

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Using the sectioning of the otoliths of Pacific cod (Gadus macrocephalus), age determination was made for a total of 1, 076 individuals collected in adjacent regions of north Japan (off the southern coast of Hokkaido, the Musashi-Tai region, off Kinkasan, and the Matsumae-Kojima-Tai region) as well as off the Kamchatka Peninsula. The seasonal changes in percentages of otoliths with a translucent edge showed that the translucent part of the otolith was an annual growth ring formed during the autumn and winter. The change in monthly mean body lengths indicated that the body length of cod increased mainly between May and September. So we used samples collected during October and March for analysis of fish growth. The analysis of von Bertaranffy's curves revealed that there was little difference in growth rates in adjacent waters of north Japan, while it was significantly lower off the Kamchatka Peninsula.

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The sex of the Japanese eel could be controlled by the oral administration of DES-Na (sodium diethylstilbestrol) which also promoted growth. Elvers were reared from glass eels for more than 500 days with a commercial feed which contained DES-Na (0, 0.5, 0.75, 1.0ppm). All the eels were dissected at the end of the experiment to check the sex by both external appearance and histological examinations of gonads. The sex groups were divided into male, male?, female, female? and unknown by their external appearance, and into male, female, hermaphrodite, and non-sex by histo-logical examination. The largest discrepancy (27.5%) in the two examinations was found in the male: the histological examination was found to be essential. The female ratio increased along with an increase in DES-Na. It was 7.7% in the control and 23.2-35.4% in DES-Na groups. The male ratio was 64.1% in the control and 32.0-40.4% in DES-Na groups. The hermaphrodite ratio was 1.1-4.6%, and the non-sexual ratio was 23.8-38.0%. Females were the largest of all sex groups. The growth promoting effect was found to vary with the growth stage.

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Our aim in this paper is to study the fishing management of stone flounder Kareius bicoloratus off the northern coast of Fukushima Pref. As the basis for such management, we investigated the price function of stone flounder each month at Souma-Haragama fish market. Using this price function, the total combination of monthly efforts throughout a year of gill net fishing which maximizes the catch amount in yen was obtained by the Multi-Stage Monte Carlo Optimization method. Comparing this with those that maximize the catch amount in yen calculated after changing to a constant price each month, we found that it was necessary to consider price as a function of catch amount.

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Wild mullet caught during the spawning season by set net in 1990 showed a sex ratio (female: male) of 27 to 34 (44.3% female). Cultured mullet of 1 and 2 years (1 +, 2 +) fed with a diet con-taining 25± protein and 3500 kcal/kg showed a female ratio of 13.0% in 607 mullet of 2 + years and of 15.7% in 643 mullet of 1 + year. Diet containing 10 ppm estradiol 17β resulted in a female ratio of >94.7% in a population of 223 1 + mullet specimens.
The mean body weight of 1 + cultured grey mullet was 900g (500-1100g). That for 2+ was 1700g (700-2500g), that for 3 + 2700g (2100-3100g). Growth rate in weight was faster in 1 + than in 2 + cultured mullets. That in total length (L; cm) of 1 + and 2 + were similar. The con-dition factor (a) for the 2 + and 3 + cultured grey mullet was 1.108+0.168, while a=1.139±0.168 for female and 1.096±0.180 for male, for female andmale will mullet were 0.850±0.043 and 0.741±0.095, respectively.
An intraperitoneal fat body (IPF) containing 94.8-98.7% lipid contributed to 4.01±2.04 to 5.44±2.53% of body weight in the 1-3 years cultured mullet. None was found in wild mullet. The hepatosomatic index was 1.03±0.43 to 1.38±0.35% and decreased with age for cultured mullet and 1.19±0.20% for wild mullet.

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Carp and red sea bream were exposed for 96h to 0.3mgCd/l in freshwater and 10mgCd/l in seawater, respectively. The cadmium tissue distributions and cadmium cytosolic partitioning in tissues were analyzed using Sephadex G-75 chromatography to estimate the toxicity in tissues. Cadmium tissue distributions in carp and red sea bream after intraperitoneal administrations of CdCl₂ and cadmium-metallothionein (CdMT) were also investigated to compare the cadmium movement in their bodies.
The exposure of carp to cadmium resulted in the highest accumulation in the gills, followed in descending order by the kidney, intestine, and hepatopancreas. The highest proportion of cadmium concentration in the HMW pool (fractions containing enzymes) relative to the MMW pool (fractions containing metallothionein) was found in the gills. These results suggest that the gills of carp are most likely to be harmfully affected by exposure to an acute level of cadmium.
The exposure of red sea bream to cadmium resulted in the highest accumlation in the liver, followed in descending order by the kidney, intestine, and gills. The cadmium concentration in the HMW pool was highest in the kidney. However, the highest proportion of cadmium concentration in the HMW pool relative to the MMW pool was found in the intestine. These results suggest that the maximum detoxification capacity was reached first in the intestine.
After the intraperitoneal administration of CdMT, a significantly high accumulation of cadmium was found in the kidney of carp but not in the kidney of red sea bream. This result suggests that the ability to trap the cadmium bound to MT in plasma by kidney may be lower in red sea bream than in carp.
In conclusion, the osmotic regulation mechanisms in fish may possibly be related to the distribution and movement of cadmium in the body.

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Fishing experiments were conducted using topshell trammel nets and bottom fish tramme nets as a control in the west of Yamaguchi Prefecture form October 1990 to June 1991. The topshell trammel nets were grouped into two types, one being the ordinary type and the other a pilot type proposed for test purposes. The latter, as compared with the former, is smaller in the height of the net and thus plays, in effect, a role in reducing fishing mortality caused by lost gear, even if the gear escapes during fishing operation, because it has the least possible amonut of netting. This kind of fishing mortality is called ghost fishing. Each of the two types was grouped into three subtypes by the mesh size of the inner net. Of a total of 391 topshells Turbo cornutus, 139 were caught by the ordinary type, 169 by the pilot type and 84 by the control nets. The mean CPUE, the catch per unit of net per average of soaking hours, was used in a statistical comparison between the catching power of the ordinary type and that of the pilot type. As a result, the topshell cathing power of these two types were nearly equal.

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Microinjection of foreign DNA into oocyte nucleus is a useful method for producing transgenic medaka. To find the most appropriate stage of oocyte maturity to obtain efficient foreign gene transfer, we microinjected the plasmid pHV-GH containing Drosophila Hsp70 promoter and rainbow trout growth hormone cDNA into medaka oocytes collected 20-6h before ovulation at intervals of 2 hours. Injected oocytes were cultured until ovulation, inseminated and incubated for 7 days. Oocytes collected 14-6h before ovulation matured in culture while most of those col-lected 20-16h before ovulation did not. The proportion of oocytes which were successfully fertilized and normally developed to the 7-day-old stage after microinjection were highest for oocytes collected at 8h before ovulation, as 79% were successfully fertilized and 58% developed normally. Embryos developed normally to the 7-day-old stage were assayed for the existence of foreign sequences by slot blotting. The proportion of embryos positive for foreign sequences among those assayed was highest (60%) for oocytes at 8 and 10h before ovulation. Thus, the gene transfer efficiency, ie. the ratio of positive embryos to injected oocytes, was highest (35%) at 8h before ovulation.

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Cultures for the gametophytes of Ecklonia kurome, Undaria pinnatifida, Eisenia bicyclis, and Ecklonia cava and the young sporophytes of E. kurome and U. pinnatifida were developed in order to study the influence of light quality and quantity on gametophyte growth and fertility, as well as sporophyte growth. Red, green, blue, and white fluorescent light was used in varying degrees of quantum irradiance. The results confirmed nearly identical tendencies for all species examined. That is, the growth of both gametophytes and sporophytes was most pronounced under blue light, followed by good growth under white and green light, with red light showing the poorest results. Fertility of gametophytes developed most quickly under blue light, and could be seen to develop more slowly under white light. Fertility showed a tendency toward delay under green and red light. Also, male and female gametophytes of Ecklonia kurome, which is distributed in deeper water at 7-20m, became fertile in lower quantum irradiance than in the gametophytes of Undaria pinnatifida and Eisenia bicyclis growing in shallow water down to 7m.

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This paper deals with the effect of net clogging on measurement for filtered water volume with a flowmeter placed at the center of a net frame. Experiments were carried out using a sampler which had two cyclinder-corn nets: one with fine mesh (0.100×0.100mm, F-net), the other with coarse mesh (0.140×0.170mm, C-net), with a ratio of mesh aperture to mouth area of 10. The sampler was towed horizontally 151 times at a speed of about 1.25m/s for 7 min.
In most of the tows, the distances which the C-net flowmeter travels (L_c) and which the F-net flowmeter travels (L_F) almose reached the expected value (525m). However, on some of the tows, L_F was much shorter than the expected value and L_F/L_c was under 0.9. On these tows, the settling volume caught with the F-net was over 100ml and the number of fish eggs caught with the F-net per 25m³ (D_F), calculated with the filtered water volume estimated from the revolution of the flowmeter's impeller, tended to be a little more than the number of fish eggs caught with the C-net per 25m³ (D_c). The correlation between D_F and D_c are indicated by a regression line of D_F=1.128 D_c. This suggests that net clogging has an effect on measurement with a flowmeter for filtered water volume.

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Karyotypes of all species of Gnathopogon and Squalidus inhabiting Japan (G. elongatus, G. caerulescens, S. chankaensis biwae, S. c. subsp. (Japanese name: korai-moroko), S. japonicus japonicus, and S. gracilis gracilis) were analyzed by conventional staining and Ag-NOR banding techniques. Both Gnathopogon species had 50 chromosomes in diploid number, and their chro-mosome complements each consisted of 7 pairs of metacentric and 18 pairs of submeta-and subtelocentric chromosomes (including 2 pairs of sat-chromosomes, with NORs). Of the four Squalidus species, each had a diploid chromosome number of 50, and the chromosome comple-ment in each case consisted of 10 pairs of metacentric and 15 pairs of submeta-and subtelocentric chromosomes (including a single pair of sat-chromosomes, with NORs). In this study, karyo-of F₁ hybrids types of S. g. gracilis (female) and G. caerulescens (male) were examined. Accord-ing to the chromosomal configuration of both parental species, chromosome size in Gnathopogon was found to be essentially the same as that of Squalidus.
Fish belonging to these genera have been classified into genus Gnathopogon collectively, or into genera Gnathopogon and Squalidus separately. Karyotypic data presented here support the latter classification. It has recently come to be considered that Gnathopogon should be assigned not to the subfamily Gobioninae but to Barbinae. However, no precise solution to the problem could be obtained by the karyotype analysis.

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The annual reproductive cycle, breeding season and shell length at first sexual maturity of the sunray surf clam, Mactra chinensis, in Tomakomai, were examined histologically. Devel-opment of the germ cells was divided into five stages; in the female, they were oogonium, yolkless stage, early yolk-formation, late yolk-formation, and mature stage; in the male, they were spermatogonium, primary spermatocyte, secondary spermatocyte, spermatid, and sper-matozoon. On the basis of cytological characteristics and the relative amount of germ cells, maturation of the gonad was classified into recovery, early growing, late growing, maturing, spawning, and spent stages. The early growing stage appeared in March, while the late grow-ing stage was found in April in the male and in May in the female. The maturing stage was observed from May to June in the male and in June in the female, while the spawning stage occurred from July to September. The spent and recovery stages appeared from Octo-ber to November and from December to February, respectively. The breeding season of the clam was estimated to be from July to September. Shell length at first sexual maturity was 25-30mm.

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Concentrations of eighteen elements in several tissues of four species of Tridacnidae from coral reefs off Ishigaki Island, Okinawa, Japan, were measured by inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry. The highest concentrations of Ca, Cd, Co, Mn, Ni, P, Pb, Sr, and Zn were found in the kidney of Tridacnidae. In particular, the concentrations of Mn and Ni in the kidney were approximately one hundred times higher than those in other tissues.
Microscopic observation of the kidney showed that intracellular granules with concentric rings were present in each cell. The granules (ca. 20μm in diameter) occupied more than a fourth of the vacuole space in the kidney cells. The concentrations of Ca, Mn, P and Sr in the granules were several times higher than those in the kidney.
From these results it was concluded that the specific accumulation of Ca, Mn, P and Sr in the kidney of Tridacnidae was related to the presence of metal-containing granules.

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Three mid-layer floating reefs made of steel were deployed at a depth of 80-90m off Tajima in the Japan Sea in May 1987. To examine the distribution of fish around the reefs, an acous-tic survey over a 3×2km area, 70-110m in depth, and ROV observations were carried out during the daytime in May and August, 1988.
Around the mid-layer reefs, Navodon modestus and Trachurus japonica were observed. Sol-itary Navodon modestus were close to the reef (within 10m) in the daytime, and were thought to settle on the reef at night. As Trachurus japonica, observed in August, was distributed around the floating reefs and a sunken ship in dense small schools, they were not seen else-where in the survey area. The mid-layer floating reef was concluded to act as a schooling ground for Trachurus japonica in the daytime.
In May, many scattering fish echoes, which were thought to be a mixture of small squid, pelagic crustacea and others, were distributed over the whole survey area. They stayed around the reef twice-a scattering fish echo stayed at the bottom layer around the reefs for more than few hours, and a dense fish school stayed beneath the mid-layer reef for a short dura-tion. These phenomena were concluded to show an attraction and detention function of the mid-layer floating reef.

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To clarify the effects of environmental water temperature on antigen kinetics in the plasma after hyperosmotic infiltration (HI) treatment, bovine serum albumin (BSA) was administered to rainbow trout Oncorhynchus mykiss by HI treatment or by intravenous injection at various water temperatures (9.0, 12.0, 15.0, 17.5, and 20°C). BSA in the plasma was determined by Laurell-rocket immunoelectrophoresis. First, using a least squares program, the BSA clearance rate from the plasma was computed from the plasma BSA levels of the fish injected with BSA at each temper-ature. Then, using this clearance rate and the plasma BSA level after the HI treatment, the de-convolution method was applied to estimate the BSA release rate into the plasma after the HI treatment. The results showed that both the BSA clearance rate and the gross BSA release were significantly correlated to the environmental temperature between 9.0 and 20.0°C (P<0.001). It is suggested that low environmental temperatures interfere with bath immunization.

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Degraded products of laminaran by the action of Clostridium ramosum were surveyed for their constituent mono-, di-, and trisaccharides by active carbon column chromatography. Trisac-charide was detected in 2% laminaran-containing GAM broth culture which was incubated with Cl. ramosum for 12h. Mono- and disaccharides were detected in 24h culture. Among 11 strains of authentic intestinal bacteria which cannot ferment laminaran, 7 and 8 strains utilized the former and latter products, respectively. Particularly, the growth of lactic acid- or acetic acid-forming bacteria such as Bifidobacterium bifidum and Peptostreptococcus productus was promoted by these degraded products. These results are considered to give experimental support to the suggestion that Bifidobacterium could grow in rats and human intestines when dietary fiber has been ingested.

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By taking advantage of the low melting point of fish oil, chilled-column reverse-phase high-performance liquid chromatography (HPLC) was examined in order to obtain good resolution of triglycerioe (TG) molecular species. TGs containing high proportions of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were synthesized by using 90% pure EPA and DHA with a bacterial lipase. Four TG molecular species thus obtained were subjected to HPLC analysis, from which the difference in retention time, theoretical plate number, and resolution of the adjacent peaks were discussed in relation to the column temperature of the system. The lower the column temperature, the better the theoretical plate number and resolution. However, they reached a maximum at around -15°C. It was concluded that low temperature, wherever it is practicable not to exceed the melting point, is the best temperature for fish oil TG molecular species analysis and fractionation

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A feeding trial was performed with the fingerling yellowtail Seriola quinqueradiata to evaluate several kinds of defatted soybean meal as a partial substitute for fish meal in the diet. Fish fed on diets including up to 20% commercially available defatted soybean meal showed just as good growth and feed efficiency as that fed on the control diet free from soybean meal and high in fish meal, while feeding with a 30% soybean meal diet appreciably depressed the performance. No marked differences were observed in the general composition of the fish body and the hematological characteristics among the groups, although the concentration of plasma zinc decreased as the soybean meal levels of the diets increased.
Of the four kinds of soybean meal (commercial meal, severely heated meal, amino acid-supplemented meal, and purified meal), the best growth rate and feed efficiency were obtained from fish fed on the diet with purified meal. While a similar and an inferior performance was found in fish fed on the diet with amino acid-supplemented and severely heated meals, respectively, in comparison to that of the commercial meal group. These findings indicate that commercial defatted meal can substitute for fish meal in up to 20% of the diet for fingerling yellowtail, while purified soybean meal such as soy protein concentrate is a better protein source.

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Sarcoplasmic protein (Sp-P) from carp Cyprinus carpio was heated at various temperatures from 20 to 100°C for 15 min at pH 7.0, and the physicochemical properties and emulsifying activity of heat-treated Sp-P were investigated.
By treatment above 40°C, the solubility of Sp-P decreased and its surface hydrophobicity and reactive SH content increased with a rise in heating temperature. For the soluble fraction of heat-treated Sp-P, the surface hydrophobicity and total SH contents at 50-100°C treatment were somewhat smaller than those at 20-40°C. A 12 kDa component largely remained soluble at 70°C or above and was assumed to be parvalbumin.
The emulsifying activity of Sp-P was minimal at 60°C, and thus it was considered to be attributable to heat-coagulable soluble proteins for the lower temperature treatment and to parvalbumin for the higher temperature treatment.

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Two feeding experiments were conducted to determine suitable dietary protein and lipid levels for fingerlings of yellowtail by feeding them with various white fish meal (and casein) diets containing different levels of protein (CP: 35-55%) and lipid (CL: 6-20%).
In both experiments, the growth rate and feed efficiency were higher in fish fed on diets con-taining around 50% CP than those fed on diets with 45% CP, irrespective of the lipid levels. The best growth was obtained in fish fed on a diet containing 50% CP with 15% CL, when the n-3HUFA level was fixed at 2.1%. On the other hand, at levels of 42 and 52% CP, the feed performances in fish fed on a diet containing a CL of more than 15% were inferior to those in fish fed on 10% CL regardless of n-3HUFA content in the diet. Furthermore, a lower growth rate was observed in fish fed on a moist pellet although the dietary CP level (CP: 63% on a dry matter basis) was the highest of all the experimental diets.
These results indicated that not only CP and CL levels but also n-3HUFA contents in the diet affect the growth of yellowtail fingerlings. It was also suggested that the suitable protein and lipid levels in the diet for yellowtail fingerlings are around 50 and 15-20%, respectively, at a level of 2.1% n-3HUFA.

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This study was conducted to clarify the relationship between dietary lipid levels and n-3 highly unsaturated fatty acids (n-3HUFA) contents, and to determine their suitable levels to sustain the normal growth of yellowtail fingerlings, by feeding them with various white fish meal diets contain-ing different amounts of lipid (6-20%) and n-3HUFA (1.4-5.9%).
At the level of 10% lipid, the elevation of the n-3HUFA level from 2.3 to 3.9% reduced growth, and fish fed on a diet containing 3.9% n-3HUFA showed the lowest growth performances. At the level of 15% lipid, good growth and feed efficiency were observed in fish fed on diets containing n-3HUFA from 2.1 to 3.1%, but further elevation of dietary n-3HUFA content resulted in reduced growth. On the other hand, at the level of 20% lipid, growth and feed efficiency improved as the n-3HUFA content increased, reaching a plateau in diets containing n-3HUFA above 3.4%.
Thus the growth of yellowtail fingerlings was influenced by dietary n-3HUFA levels, and the n-3HUFA content in diet was recommended to be increased in proportion to dietary lipid levels to obtain maximum growth. Moreover, it was also found that the upper limit of suitable n-3HUFA level in the diet was approximately 22% of dietary lipid, irrespective of lipid levels, and that the suitable lipid level in the yellowtail diet was estimated to be 15-20% when n-3HUFA was adjusted to a suitable level.

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To elucidate the utilization of dietary methionine in rainbow trout, a feeding experiment was conducted. Five experimental diets were prepared: Diet 1, a basal diet containing 50% casein as a sole protein source; Diets 2 to 4, L-methionine was supplemented at levels of 0.5, 1.0, and 1.5% to the basal diet, respectively; Diet 5, containing 50% egg white albumin as a protein surce. The fish fed on the methionine-supplemented diet accumulated large amounts of methionine in both the liver and muscle. Unlike methionine contents, hepatic taurine contents were slightly affected by the dietary treatments. Net protein utilization (NPU) was improved by supplementation of methionine up to 1.0 %. However, NPU of fish fed on the diet supplemented with 1.5% methi-onine was lower than that of the 1.0%, methionine diet. These results suggest that rainbow trout has limited ability to convert methionine to cysteine via a transsulfuration pathway, and that dietary methionine was not utilized effectively when fish were fed with a large amount of methionine.

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In order to elucidate changes in the nutritive value of defatted soybean meal with the duration of heating time, the general and amino acid composition and trypsin inhibitor (TI) activity of several types of meal heated at 108°C for 0-40 min were determined, and the growth, feed conversion, protein digestibility, and body composition of young yellowtail Seriola quinqueradiata were also compared by feeding them with diets containing about 20% of each meal.
The nutritive value of raw defatted soybean meal was extremely low: it had a high TI activity and high nitrogen solubility index, resulting in a low protein digestibility; its feeding caused weight loss in fish with inferior hematological characteristics and body composition. The nutritive value of the meal was markedly improved by heating it for 20 min, and was maximized by heating it for 30 min, but it decreased slightly after being heated for 40 min. The heating treatment hardly improved the general and amino acid composition of the soybean meal, while it caused a rapid inactivation of TI together with a marked improvement in protein digestibility, indicating that the improvement of its nutritive value by heating could be mainly attributed to an elimination of heat-labile growth inhibition factors such as TI. Also, the comparison in nutritive value between these heated soybean meals and soy protein concentrates suggests the continuing existence of heat-stable growth inhibition factors in the heated meal.

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To clarify the difference in the three-dimensional structure of collagen fibrillar networks of several muscles, a cell-maceration/scanning electron microscope (SEM) method was applied for tiger puffer, sardine, carp, and rabbit muscles in parallel to evaluate muscle firmness. Tiger puffer and rabbit muscles, whose texture was relatively firm, had collagen fibrils of higher density in the pericellular connective tissues. Sardine muscle which was relatively soft in texture, on the other hand, had connective tissue which was scarce in collagen fibrils. The arrangement of collagen fibrils also differed among fish species. The collagen fibrils of sardine and carp muscles were highly ordered, while those of tiger puffer and rabbit were less ordered. These results suggested that the difference in muscle firmness was related to both the density and the arrangement of collagen fibrils in the pericellular connective tissue. In addition, it was indicated that the cell-maceration/ SEM method was effective in observing the three-dimensional structure of collagen fibrillar network in connective tissue of muscle.

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The effect of various culture conditions on tetrodotoxins formation was studied using a strain F-9 isolated from the puffer fish Takifugu rubripes. The strain was identified as that similar to Vibrio nereis. The TTXs formation by the strain was proved by GC/MS analysis and the major toxin was identified as 4-epi TTX by HPLC. ORI medium gave a high toxin formation. Cells in the stationary phase showed a high toxicity. As compared with static culture, shaking culture was suitable for high toxin formation. Optimum temperatures for both growth and toxin formation were 27.5°C, but optimum NaCl concentrations for growth and toxin formation were 3 and 5%, respectively. These results suggested that various culture conditions influenced the productive ability of tetrodotoxins in the strain.

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The iodine distribution of finely divided blades of Laminaria (mitsuishi-kombu, ma-kombu, and cultured ma-kombu) was studied by an electrochemical detector with an IRICA RP-18T (reverse phase ODS) column using samples subjected to alkali combustion. In the case of Mitsuishi-kombu (Laminaria angustata), iodine contents were relatively high in the basal parts. Iodine contents in on sample of Ma-kombu (Laminaria japonica) were found to be high in the upper parts, while those of other samples were considerably high in the basal parts. In cultured Ma-konbu (Laminaria japonica) while those of other samples central parts contained more iodine than other parts. The sums of iodine contents obtained from the divided samples were 230-340mg/100g in Mitsuishi-kombu, 130-289mg/100g in Ma-kombu, and 180-245mg/100g in the cultured Ma-kombu, respectively.

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