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Comparative fishing trials were undertaken with two commercial collapsible pots for the crab Charybdis japonica. One pot was box-shaped with two slit entrances at the ends, while the other was dome-shaped with two open funnel entrances. Pots were placed at the bottom of a pond that is connected to Kagoshima Bay. Fishing trials were carried out using a 1-day soaking time; the bait used was mackerel. The box-shaped pot had higher catches of crabs and non-target organisms, but the number of large crabs (carapace width >8 cm) was almost half as many as that caught with the dome-shaped pot. The catch of non-target species was also greatly reduced in the dome-shaped pot, and fish caught were mostly enmeshed in the netting. The reduction in catches of small crabs and non-target organisms was due to the nature of the dome-shaped pot's larger mesh size and open entrances, which allowed for escape. The dome-shaped pot seemed more efficient for harvesting commercial size crabs, while the box-shaped pot seemed better for removing all crab sizes. [ABSTRACT FROM AUTHOR]

Conspecific predation among longnose lancetfish Alepisaurus ferox was investigated in four spatio-temporal strata of the western Indian Ocean. The cannibalism level varied from 0 to 45.5% by frequency of occurrence and was negatively related with abundance of non-evasive prey (such as crustaceans Charybdis smithii and Natosquilla investigatoris) and foraging success. Predation by lancetfish is often described as a non-selective process, constrained by local prey availability and by its feeding speed during an attack of prey. Our results show that lancetfish may adapt its opportunistic foraging behavior, feeding on non-conspecific abundant prey such as crustaceans when available, and switching to a high level of conspecific predation in poor waters. [ABSTRACT FROM AUTHOR]

An underwater camera was used to record the behavior of the crab, Charybdis japonica , towards two baited pots. These were commercial collapsible pots commonly used by Japanese fishermen to catch crabs. One was box shaped with two slit entrances at the ends, while the other was dome shaped and had two open funnel entrances. The pots were placed on the bottom of a pond that was connected to Kagoshima Bay, southern Japan. Underwater video recordings were used to study the different behaviors of the crabs towards the two types of pot. Crabs approached the pot mostly by crawling up current (75%) following the bait odor trail. They made several attempts to enter the pot until they reached the entrance or otherwise they gave up. While the dome-shaped pot allowed the crabs to enter it easily by crawling sideways, the box-shaped pot's tight slit entrances and netting material prevented the crabs from getting in due to entanglement of their spines on the netting. Ingress could only be achieved after several trials and mostly by crawling backwards into the pots. The dome-shaped pot was more efficient (100%) than the box- shaped pot (31%) in catching crabs that came in contact with it. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effects of net height on the capture performance of crab entangling nets. Fishing trials were conducted using nets at varying net heights (1) 12 meshes down (MD), (2) 24 MD and (3) 50 MD. A total of 1290 individuals comprising 87 species belonging to 53 families were caught. One-way analysis of variance showed that net height significantly affected the various catch parameters, including catch per unit effort (CPUE) of the total and target catch, amount of non-target catch, size of catch and species richness. The use of appropriate net height is a potential technical measure for a selective but still efficient crab entangling net fishery. Lower net height significantly reduced non-target catch by up to 70%. Lower net height also decreased the CPUE of target catch such as Portunus pelagicus and Charybdis feriatus by up to 65% at 12 MD, but catch at 24 MD was not significantly different than that at 50 MD. The use of a net height of 24 MD also resulted in the capture of larger-sized P. pelagicus. The richness of the catch species decreased by up to 58% in lower nets. These results are useful to fishery managers and government institutions when developing and/or improving existing regulations towards a sustainable crab fishery, particularly blue swimming crabs. [ABSTRACT FROM AUTHOR]

Small-bodied sharks are recognized as mesopredators on different communities in a large variety of habitats, thus linking the trophic levels in the marine ecosystem. Dietary analysis on these species can provide insight into the trophic relationships in food webs. Our study analyzed the diet composition of Galeus sauteri, an abundant small shark inhabiting neritic shelf waters at depths between 60 and 200 m. For this purpose, a stomach content analysis was realized in 678 specimens collected by bottom trawlers off northeastern Taiwan from September 2018 to August 2019. The two most commonly consumed preys were teleosts (prey-specific index of relative importance, %PSIRI = 51.94) and crustaceans (%PSIRI = 30.08).The results for the Levin's index (Ba = 0.06) and graphical analysis based on the Costello method revealed a high degree of specialization on lanternfishes and other teleosts. The mean trophic position was 4.29. Feeding habits differed significantly in relation to maturity condition and between seasons. Our result showed that G. sauteri is a primary piscivorous shark that preys mainly on lanternfishes and other teleosts, and feeds opportunistically on crustaceans and cephalopods. [ABSTRACT FROM AUTHOR]

Aquatic organisms detect chemical cues to sense the local environment, for example, to find a mate, locate food, and identify danger. Knowledge of chemical cues can be used in aquaculture, in practical applications such as controlling mating behavior to increase fertility, enhance feeding, and decrease stress; in fisheries, by catching selected species with low-cost artificial attractants; and to address maritime issues, by decreasing biofouling. Aquatic organisms also detect chemical cues related to global environmental changes, ocean acidification, and increases in ocean plastics, all of which can affect their chemosensory behaviors. Here we discuss the nature of chemical cues and chemosensory biology and ecology of aquatic organisms, and potential applications with an emphasis on sex pheromones in commercially important and well-studied animals, namely, decapod crustaceans and fish. [ABSTRACT FROM AUTHOR]

This study evaluates the impacts of mesh size of the net, fishing depth and season on the catches of target, non-target and discarded species for short mackerel Rastrelliger brachysoma gillnet fishery in the vicinity of Pattani Bay, Gulf of Thailand. The catches were examined for species composition, catch efficiency and size of catch. Samples were obtained monthly from February 2019 to February 2020 at three fishing depths (2.0, 4.0 and 6.0 m) using gillnets with three different mesh sizes (3.0, 4.0 and 4.5 cm). Including the target species, 112 species were collected, the majority of which were non-targeted fishes and crustaceans. The target species, Rastrelliger brachysoma, contributed only 6.0% by number and 8.76% by weight to the total catches. The 111 non-target species were classified into five categories based on potential sale prices. A total of 18 species, equivalent to 3.04% by weight of the total catches, were considered to be of negligible value and discarded or sold for the production of fish meal. Temporal variability was observed for number of individuals and biomass of total catches; the compositions of the catches clustered to two distinct seasons from December to March and from April to November, respectively. Spatial variability in this study focused on the depth profile which was found to significantly influence species richness and sizes of some fish species. For 12 species, mesh sizes of the gillnets significantly affected the number of individuals caught, as well as their weight and sizes. The novel findings of this study provide essential information that can be used for the sustainable management of the Rastrelliger brachysoma fishery in the Gulf of Thailand. [ABSTRACT FROM AUTHOR]

Bristle patches on the carapace behind the eyes were found for the first time in both males and females of the four species of mud crab Scylla spp. Electrocardiography revealed that the bristle patches of Scylla paramamosain were sensitive to touch (with a glass capillary) but not to chemical stimulation (with sugarcane juice). To elucidate the function of these touch signals, the courtship behaviour of S. paramamosain was video-recorded in a broodstock tank. A male approached a female, extended a walking leg over her carapace, touched her bristle patches with a dactyl, mounted her, and probed the bristle patches further with the third maxillipeds. Touch stimulus may be a signal for courtship in Scylla and one of the chain stimuli for the completion of mating behaviour. [ABSTRACT FROM AUTHOR]

Chondroitin sulfate synthase-1 (ChSy-1) plays an important role in the synthesis and chain extension of chondroitin sulfate (CS). CS, a linear polysaccharide with high structural diversity, plays crucial roles in cell adhesion, morphogenesis and cell division in response to viral and bacterial infections. However, the role of ChSy-1 in the immune response remains unknown. In the present study, ChSy-1 from Pinctada fucata was identified. The deduced amino acid sequence of ChSy-1 contains a conserved domain, CHGN, which belongs to glycosyltransferase family A, and multiple sequence alignment revealed that CHGN shows evolutionary differences. Phylogenetic analysis indicated that ChSy-1 may be conserved evolutionarily. The nucleus grafting experiment showed that ChSy-1 possibly participates in wound repair and immune response to the graft. Lipopolysaccharide or polyinosinic:polycytidylic acid challenge and gene expression analysis especially suggested that ChSy-1 is involved in the immune response. The results of the present study indicate that ChSy-1 plays a role in the protection of the pearl oyster against infectious diseases. [ABSTRACT FROM AUTHOR]

The Chinese mitten crab Eriocheir japonica sinensis is one of the most common aquaculture species cultivated in China. The crab is an omnivore, and its hepatopancreas absorbs and stores nutrients. The aim of this study was to elucidate the expressions of the digestive enzyme genes and determine their respective roles in regulating digestive capacity in E. j. sinensis. We sequenced the hepatopancreatic transcriptomes of crabs fed a meat diet (MD), a vegetarian diet (VD), or a mixed diet (MV) and compared the gene expression patterns of these three groups of crabs. A total of 305,887 unigenes were obtained, of which 8747, 10,963, and 8877 were significantly differentially expressed in the comparisons between the MD and MV, VD and MV, and MD and VD diets, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) database-based enrichment analysis revealed that the differentially expressed gene (DEG) responses in the hepatopancreases to the MD mainly involved the "pancreatic secretion," "glutathione metabolism," "sphingolipid metabolism," "fatty acid metabolism," and "glycerolipid metabolism pathways." DEG responses to the VD based on KEGG analysis mainly involved the "galactose metabolism," "starch and sucrose metabolism," and "fructose and mannose metabolism" pathways. The key digestive enzymes, including trypsin, β-glucosidase, chitinase, and triacylglycerol lipase, were identified. Our results further our understanding of crustacean hepatopancreatic functions during food digestion and provide resources for further studies regarding the molecular basis of omnivorous diets in crustaceans. [ABSTRACT FROM AUTHOR]

Ribosomal protein S6 kinases (S6Ks) are key targets downstream of the mechanistic target of rapamycin (mTOR) signaling pathway that are activated by mTOR complex 1 phosphorylation to promote protein synthesis, and are involved in muscle growth and pathology. In this study, we cloned a 1560-base pair (bp) complementary DNA sequence encoding a unique S6K1, designated EsS6K1, in the Chinese mitten crab Eriocheir sinensis. EsS6K1 contains a 54-bp 5′ untranslated region, a 246-bp 3′ untranslated region and a 1260-bp coding sequence that encodes 419 amino acids. EsS6K1 contains a conserved kinase domain, a TOR signaling motif, and a turn motif; it lacks a C-terminal autoinhibitory domain, and the conventional threonine in the hydrophobic motif is replaced with serine. Real-time quantitative reverse transcription–polymerase chain reaction experiments showed that EsS6K1 expression was highest in the ovaries, followed by the testes and the eyestalks, in mature crabs. In juvenile crabs, the relative messenger RNA levels of EsS6K1 in the claw, walking leg and abdominal muscles were significantly higher in the late premolt (D3-4) stage than in the intermolt (C) stage. After ecdysis, the expression of EsS6K1 in the walking leg and abdominal muscles declined to the level in the C stage, but the expression in claw muscles remained as high as that in the D3-4 stage. The findings showed that EsS6K1 likely plays roles in muscle changes during crustacean molting. These results provide valuable insights into the mechanism underlying crustacean muscle growth induced by molting. [ABSTRACT FROM AUTHOR]

Ecological literature on abalone Haliotis discus hannai populations is reviewed to identify processes and factors driving ontogenetic shifts in habitat. Abalone recruitment is related to the algal community type, with abalone shifting with growth from deeper crustose coralline algal (CCA) habitats to shallower kelp bed habitats via algal turfs. Timing of the habitat shifts is linked to ontogenetic changes in diet, from benthic diatoms to a diet dominated by macroalgae. Susceptibility to predation appears to change, concomitant with the shift from cryptic microhabitats during early-life stages to more exposed habitats during latter-life stages. Interstitial spaces between cobbles and boulders in the CCA habitat are considered to be important for reducing predation risk. The loss of CCA nursery habitat through sedimentation and macroalgal overgrowth likely negatively affects abalone recruitment. Preservation of diverse algal communities, including suitable habitats for the different abalone growth stages, is critical for successful abalone recruitment. [ABSTRACT FROM AUTHOR]

Portunus trituberculatus broodstock were stocked in plastic tanks to evaluate the effects of starvation and feeding on gonadal development, blood chemistry, fatty acid composition, and expression of vitellogenin ( Vtg) and fatty acid-binding protein genes ( FABP) in females. Two treatments (starved and fed) were randomly assigned to triplicate groups of 90 swimming crab broodstock (approximately 230 ± 45 g). In the starved treatment, crabs were starved for 30 days, whereas in the fed treatment crabs were fed once a day with clams. The gonadosomatic index decreased significantly in starved crabs ( P < 0.05), as did the serum glucose and cholesterol concentrations; conversely, the total protein concentration in serum significantly increased ( P < 0.05). In the ovary, there was a significant relative decline of 18:0, 16:1n-7 and 20:1n-9 fatty acids and relative increases of 20:4n-6, 22:6n-3, 18:1n-9 and 20:5n-3 in starved crabs compared to fed crabs ( P < 0.05). Relative expression of Vtg in the ovary decreased significantly in starved crabs ( P < 0.05), while there was no significant difference in hepatopancreas Vtg expression between starved and fed crabs ( P > 0.05). Starvation suppressed gonadal development in female swimming crab broodstock. [ABSTRACT FROM AUTHOR]

Odorants were extracted from four Coilia ectenes (Yangtze River- Coilia, East China sea- Coilia, Chao Lake- Coilia and Yellow River- Coilia) by MonoTrap™ and analyzed by the headspace-monolithic material sorptive extraction technique combined with gas chromatography-mass spectrometry-olfactometry (GC-MS-O). A total of 63 volatile compounds were identified. The results of GC-MS-O analysis associated with odor intensity revealed that trimethylamine (fishy, ammonia-like), 1-penten-3-ol (mushroom, cabbage), N, N-diethyl-formamide (roasted meaty), hexanal (grassy, earthy), ethylbenzene (nutty, floral), (Z)-4-heptenal (fishy, boiled potato), benzaldehyde (almond, metallic), 1-octen-3-ol (mushroom, cabbage), nonanal (oily), and decanal (green, oily) were the important odorants in the four species of Coilia ectenes. Furthermore, trimethylamine and 1-penten-3-ol were common to four Coilia ectenes. TMA (fishy, ammonia-like), 1-penten-3-ol (mushroom, cabbage), N, N-diethyl-formamide (roasted meaty), hexanal (grassy, earthy), (Z)-4-heptenal (fishy, boiled potato), and benzaldehyde (almond, metallic) were included in Yangtze River- Coilia; TMA, 1-penten-3-ol, ethylbenzene (nutty, floral), (Z)-4-heptenal, 1-octen-3-ol (mushroom, earthy), and nonanal (oily) in East China sea- Coilia; TMA, 1-penten-3-ol, ethylbenzene, 1-octen-3-ol and nonanal in Chao Lake- Coilia; and TMA, 1-penten-3-ol, hexanal, (Z)-4-heptenal, 1-octen-3-ol and decanal (green, oily) in Yellow River- Coilia. [ABSTRACT FROM AUTHOR]

Trap experiments were conducted using wild and artificially reared juvenile Japanese flounder in various conditions as baits in a flounder nursery habitat of Mano Bay. All of the live wild flounder placed in the traps with sand survived in good health. However, most of the live wild flounder in the traps without sand and live-reared flounder in the traps with and without sand, as well as injured and dead-reared flounder, were consumed and stripped to skeletons overnight. A large number of the lysianassoid Orchomene sp. and Orchomene naikaiensis, and the cypridinid Vargula hilgendorfii, which are typical scavengers, accumulated in the traps with consumed flounder; however, few amphipods and ostracods occurred in traps without consumed flounder. Thus, once flounder are detected and reached by a swarm of these crustaceans, flounder may be preyed on, irrespective of the condition of the fish. This finding is supported by aquarium observations that amphipods and ostracods were able to kill and consume live flounder. Burial in sand will potentially prevent the crustaceans from detecting wild flounder by interfering with the odor from the fish. The results of our study raise the possibility that scavenging crustaceans are able to predate hatchery-reared flounder released in the sea. [ABSTRACT FROM AUTHOR]

In seedling production of seawater fish, providing appropriate nutrition is a necessity for successful production of quality larvae and juveniles. Mass-produced live prey organisms, such as the rotifer Brachionus plicatilis species complex and brine shrimp Artemia spp., alone do not provide sufficient nutrition to the larvae and juveniles of seawater animals. This inadequacy has led to various problems related to fish quality and health, including increased incidence of morphological and behavioral abnormalities and mass mortalities. It is, therefore, important to identify the factors associated with these problems to improve seedling production techniques. This review collates the efforts made during the past two decades in larval nutrition-focusing on advances made in the use of certain nutrients, such as docosahexaenoic acid, vitamin A derivatives, and taurine that are important for the mass production of seawater fish larvae and juveniles-with an aim to improve the quality and health of fish. [ABSTRACT FROM AUTHOR]

The System of Unwants Ramp-way Filtered-Bycatch Reduction Device (SURF-BRD) was developed to reduce shrimp bycatch in a shrimp beam trawl. It consists of a pair of rectangular net panels, namely, the front panel (FP) and rear panel (RP), and two fish escape vents. In this study, numerical models for expressing available selection by the SURF-BRD were proposed and assessed in several fishing experiments conducted using two types of the BRD: a prototype and an improved type with the BRD attached at a higher point on the side-nets . Contact probability and selectivity parameters of the FP and the RP for four major species were estimated for each BRD type. The improved type with the higher BRD showed a larger contact probability for the FP. Size selectivity of the FP and RP for two species (cinnamon flounder and spotted swimming crab) was almost equivalent to the mesh selectivity of the net panel, but that for lizard fish seemed to depend not on mesh size of the FP but on the swimming behavior of the fish. These results suggest that the smaller mesh size of the RP would be helpful for releasing more fish of smaller size and to exclude more spotted swimming crab, which hinder on-deck sorting by fishermen. [ABSTRACT FROM AUTHOR]

We examined the effect of bottom feeding and net chasing as means to improve the maladaptive off-bottom swimming of hatchery-reared Japanese flounder Paralichthys olivaceus juveniles for stock enhancement. Three treatments were tested: (1) a bottom feeding treatment in which fish were fed near the bottom; (2) a net chasing treatment in which fish were chased by a hand net two to four times a day, and (3) a surface feeding treatment in which fish were fed from the surface (control treatment). Foraging behavior at the surface with surface feeding was analyzed 1 day before initiating these treatments and 2 weeks thereafter. A comparison of the pre- and post-treatments revealed that off-bottom swimming was less in the bottom feeding treatment and net chasing treatments. A comparison of off-bottom swimming in the bottom feeding treatment between the pre- and post treatments revealed that bottom fed fish showed less off-bottom swimming than surface fed fish. These findings suggest that fish behavior can be manipulated during the rearing period and that such manipulations can be used to improve the behavior of fish for release. [ABSTRACT FROM AUTHOR]

Crustaceans produce complex yolk proteins to meet the substrate and energy requirements of embryonic development. Early electron microscopic investigations point to a biphasic yolk synthesis, first within the ovary, followed by heterosynthesis at extra-ovarian sites. Recent advances in molecular techniques have enhanced our understanding of the genetic control of yolk synthesis in crustaceans. Amino acid sequencing of crustacean vitellogenin (Vg) has enabled the elucidation of the cDNA sequence associated with it, the identification of genes, and the examination of their expression patterns in different tissues. Yolk processing in crustaeans involves cleavage of the pro-Vg at consensus sites by subtilisin-like endoproteases within the hepatopancreas, hemolymph and oocytes. The structural elucidation of crustacean yolk proteins, as well as the comparison of amino acid sequences of vitellogenins from various crustacean species, has revealed molecular phylogenetic relationships not only among them but also with other large lipid transfer lipoproteins of disparate function. The combinatorial effects of eyestalk neuropeptides and a variety of trophic hormones achieve the hormonal coordination of molting and reproduction. Biogenic amines secreted by the central nervous system may also play an integrative role by stimulating neuropeptide secretion. [ABSTRACT FROM AUTHOR]

Sea cucumber Apostichopus japonicus juveniles acclimated to different environmental conditions (23, 25, and 27°C combined with 25, 30, and 35 psu) were assessed for tolerance to increasing and decreasing levels of salinity at a rate of 2 psu h−1. They were also tested for the LS50 (median lethal salinity) when transferred directly into a series of higher salinity (32–46 psu) and lower salinity (9–25 psu). The CSMax (critical salinity maximum), CSMin (critical salinity minimum), USTL (upper salinity tolerance limit), and LSTL (lower salinity tolerance limit) were positively correlated to the acclimated salinity level but negatively correlated to temperature. The CSMax of A. japonicus was 6.2–10.0 psu higher than the USTL, and the CSMin was 5.5–8.5 psu lower than the LSTL, indicating that gradual changes in salinity resulted in the wide range of salinity tolerance that was observed, but that abrupt changes in salinity resulted in the narrow range of tolerance. Two-way analysis of variance revealed that salinity and temperature had a significant effect on 50% CSMax, 50% CSMin, USTL, and LSTL ( P < 0.001). The information obtained in this study will be valuable for the further development of the sea cucumber aquaculture industry in China. [ABSTRACT FROM AUTHOR]

Important crustacean fisheries occur in semi-enclosed seas. These fisheries can be strongly affected by intense exploitation and episodic anthropogenic and climatic events, but the effects of such events remain largely uninvestigated. To assess the influence of such factors, we examined dredge catch data on the gazami crab Portunus trituberculatus in Osaka Bay, Japan from 1984 to 2008 and investigated various associated environmental factors. There were five peak monthly catches during the study period, which typically occurred in August or November. Relative abundance (measured as catch per unit effort) in August was positively associated with previous recruitments to the fishery, typhoon frequency, and dissolved oxygen saturation during the juvenile period. In comparison, relative abundance in November was strongly correlated with the number of typhoons and was also positively associated with dissolved oxygen levels in the bottom water. The results of our multi-decadal study suggest that hypoxia is a principal agent of mortality for juvenile crabs and that normoxia in the nursery habitats is a necessary condition for the successful recruitment of individuals into the adult population. The positive influence of typhoons on recruitment is probably due increased mixing in stratified coastal waters, which disrupts the persistent hypoxia in bottom waters, but other unknown processes may also contribute to favorable recruitments. [ABSTRACT FROM AUTHOR]

Laboratory experiments were firstly conducted to determine the possibility of modification of the collapsible pot for blue swimming crab Portunus pelagicus by designing appropriate escape vents in terms of shape, position, and size to improve size selectivity by reducing the catch of immature crabs. In laboratory observations, nearly square-shaped vents of 35 mm height and 45 mm length, located at the lower part of the side panel, showed the best performance to allow the escape of immature-size crabs by side-crawling escape behavior through the vents, with L 50% selection carapace length (CL) of 39.1, 44.4, and 48.7 mm CL for 40, 45, and 50 mm vent length, respectively. Comparative fishing trials between conventional and vented pots with vents of 35 × 45 mm size were conducted to examine the crab size and species selectivity. Use of the vented pots was found to reduce the number of immature crabs in the catch from 70.5% to 11.0% on average, while not affecting the catch efficiency of mature-size crabs. The vented pots also had a selective effect for reducing the catch of bycatch species in comparative fishing trials. [ABSTRACT FROM AUTHOR]

A subject index for the December 2008 issue of "Fisheries Science" is presented.

A subject index for the December 2007 issue of the "Fisheries Sciences" is presented.

In order to determine the effects of ghost fishing by lost gill nets, the relationship was examined between soak time and number of enmeshed animals in experimentally lost gill nets by using diving observations. Two experimental gill nets were set at 13 m depth in Tateyama Bay, Chiba Prefecture, Japan for approximately 200 days. One gill net was deployed in a small trough surrounded by artificial reefs, and the other was deployed on an adjacent open sandy bed. Twelve species of crustaceans, six species of gastropods, and five species of bony fish were enmeshed in the experimental gill nets. The number of enmeshed animals in the artificial reef gill net was substantially larger than that in the sandy bed gill net. The number of enmeshed animals in the experimental gill nets increased rapidly within one month after deployment, and then declined gradually showing fluctuations caused by the decrease in newly enmeshed animals, and the drop off from gill nets caused by the decomposition of dead animals. The decrease in the number of enmeshed animals was expressed by logarithmic equations, and based on these equations, the duration of capture function for the lost gill nets was calculated to be 284–561 days in the artificial reef gill net and 200 days in the sandy bed gill net. The duration of capture function for the lost gill nets for non-commercial by-catch species such as small crustaceans and gastropods was longer than for commercial species such as Japanese spiny lobster and bony fish. [ABSTRACT FROM AUTHOR]

The major allergen (named Oct v 1) in the muscle of the octopus Octopus vulgaris was purified by gel filtration on Sephacryl S-300, anion-exchange fast protein liquid chromatography on Mono Q and reverse-phase high-pressure liquid chromatography on TSKgel Octadecyl-4PW. In addition to the molecular mass, amino acid composition and cross-reactivity with Tur c 1 (turban shell Turbo cornutus allergen), the determined partial amino acid sequence clearly demonstrated that Oct v 1 is tropomyosin, similar to the known molluscan and crustacean allergens. Using peptide fragments isolated from the lysylendopeptidase digest of Oct v 1, competitive enzyme-linked immunosorbant assay inhibition experiments showed that IgE-binding epitopes of Oct v 1 are contained in two peptides (77–112 and 148–160) in the central region and one peptide (269–281) in the C-terminal region. In the peptide 77–112, the same sequence as the IgE-binding epitope proposed for Cra g 1 (oyster Crassostrea gigas allergen) is recognized at 92-105. Moreover, the peptide 148-160 partly overlaps with the IgE-binding epitopes suggested for Pen i 1 (shrimp Penaeus indicus allergen) and Pen a 1 (shrimp Penaeus aztecus allergen), and the peptide 269–281 with those for Tur c 1 and Pen a 1. [ABSTRACT FROM AUTHOR]

Stomach contents were examined from 936 individuals of Mustelus manazo, collected by trawl at five locations: Aomori, Tokyo Bay, Maizuru and Shimonoseki in Japan, and one location off Taiwan. The vacuity index was relatively low (0--6.1%). Based on three indices (%W, %F, RI), the major dietary component was crustaceans at all locations. The most important prey category was crabs in Aomori, Shimonosei and Taiwan, mantis shrimps in Tokyo Bay, and shrimps in Maizuru. Fishes were a minor food category for M. manazo in most locations, except in Maizuru where fishes were second in importance in the diet. Dietary overlap revealed a medium degree of overlap between Tokyo Bay and Aomori, and between Tokyo Bay and Shimonoseki. The other locations showed a high degree of overlap with each other. Significant ontogenetic dietary shifts were found in Tokyo Bay, Maizuru and Taiwan, and prey diversity showed a trend being relatively low in larger size classes. The feeding habit of M. manazo was unique in Tokyo Bay, where crustaceans in the muddy substrata were taken in preference to the most abundant benthic prey item available, such as a southern rough shrimp, Trachypenaeus curvirostris. Mustelus manazo appears to use two feeding strategies based upon stomach contents. One, in Tokyo Bay, involved the digging up or removing of burrowing inver-tebrates from muddy substrata without crushing them. The other, at the other four locations, involved the crushing of prey on the substrata surface. [ABSTRACT FROM AUTHOR]