Cannibalism in Japanese flounder juveniles, Paralichthys olivaceus, reared under controlled conditions

Laboratory experiments were conducted to determine the effects of sand substratum, light, starvation, fish density and size variation on cannibalism among Japanese flounder juveniles, Paralichthys olivaceus. Cannibalistic behavior (biting and swallowing) increased significantly with starvation except in darkness, where juveniles could not find and attack their prey. Cannibalism occurred more frequently in heterogeneous than in the homogeneous size groups. Cannibalism was more frequent in light than in darkness at each starvation level. With sufficient food present, sand had no significant effect on cannibalism among homogeneous size juveniles, but played an important role in discouraging predation among members of the heterogeneous size groups. With sufficient food present, the rate of cannibalism was generally low and there were no significant differences in cannibalism among fish density levels of the homogeneous juveniles, With starvation, the cannibalism rate was significantly higher in high density groups than in the lower ones. Our results indicate that size variation, starvation and Light are the major factors affecting cannibalism in flounder juveniles, while sand and fish density only have a limited effect on cannibalism, depending on the nature of other factors. (C) 2000 Elsevier Science B.V. All rights reserved.

Feeding behaviour of Japanese flounder larvae under laboratory conditions

Tank-reared Japanese flounder larvae, Paralichthys olivaceus, had a major feeding peak in the morning and a secondary peak in the afternoon throughout the larval development, with light being the primary factor regulating their feeding activity. The larvae consumed rotifers in preference to Artemia for up to 10 days, after which the food preference shifted to Artemia. Feeding rates of the larvae prior to 10 days post-batch depended on prey density, but in the old larvae, feeding rates were independent of prey density. Maximum feeding rate occurred at 19 degrees C. The occurrence of the attack posture, after its onset at first feeding (2 days post-hatch), increased up to 25 days, began to decrease when the larvae prepared to settle down, then disappeared after settlement. The occurrence frequency of the attack posture was positively related to fish density, but inversely related to starvation duration, and occurred most frequently at 19 degrees C. This posture depended on prey density in larvae prior to 10 days post-hatch, but became independent of prey density as the larvae developed. It was obvious that, for flounder larvae, attack posture was a behavioural character closely related to feeding and subject to larval development and environmental factors. (C) 2000 The Fisheries Society of the British Isles.

Locomotor activity rhythm in the Japanese eel Anguilla japonica elvers

Under artificial LD cycles (6, 12, 18 L), the elvers of Japanese eel, Anguilla japonica, showed a 24 h cycle of locomotor activity rhythm being most active at light transitions: the eels' activity rose to a primary peak after lights-off, followed by a quiescent period during which they buried into the shelters or lying motionlessly on sand for most of the time, and then reached a secondary peak before lights-on. Elvers could resynchronize their activity rhythm with a new photo cycle within 4 d. Moreover, their activity level at dark phase significantly increased as the light period was prolonged: higher activity levels during shorter dark period. However, the elvers did not display clearly the existence of a circadian rhythm under constant light or dark conditions. The timing of daily activity rhythm evidenced in the Japanese eels may occur through the action of the LD cycles with a weak participation of an endogenous circadian system. In all the LD cycles, over 99% of the activity occurred in the dark phase, indicating that the eels were always nocturnally active no matter what time of day it might be. Under 12 L conditions, the eels' activity level and the time outside sand were significantly elevated both at light and dark phases as temperature increased from 10 similar to 15 to 20 similar to 25 degrees C. The activity rhythm pattern (i.e., two peaks occurring around light transitions) did not apparently change among temperatures. However, in contrast with the primary activity peaks immediately after lights-off at 20 and 25 degrees C, the timing of the primary peaks at 10 and 15 degrees C showed a latency of a few hours following lights-off, indicating the inhibiting effect of low temperature on the eels' activity.

Observations on the spawning behavior of artificially matured Japanese eels Anguilla japonica in captivity

Spawning behavior of artificially matured Japanese eels Anguillo japonica in captivity was investigated using a DVD Video image system. Following a routine hormone treatment technique for this fish, female eels were artificially matured by weekly intramuscular injections of salmon pituitary extracts (SPE) at a dosage of 40 mg kg(-1) BW for a total of 7-11 doses to induce ovarian maturation, while male eels received weekly intramuscular injections of human chorionic gonadotropin (HCG) at a dosage of 1000 IU kg(-1) BW for a total of 6-11 doses at 18 degrees C to induce testicular maturation in a separate aquarium. In this experiment, three pairs of such hormone-treated matured eels were acclimatized in seawater in 1.5 m(3) experimental aquaria with or without shelters at 20 degrees C for 24 h. Twenty four hours after the acclimatization terminated, the females received SPE injections to boost maturation and ovulation. Twenty four hours following these injections, the females received injections of HCG (1000 IU per fish, HCG injection) and 17 alpha-hydroxyprogesterone (2 mg per fish) to induce ovulation, while males were given HCG injections (1000 IU per fish, HCG injection) to induce spermiation. Video taping started after the 24 h acclimatization terminated and last for a total of 96 h. Before the HCG injections, both sexes were inactive, staying on the bottom or in shelters if available. Following these HCG injections, they became active and frequently left the bottom swimming in the water column. During the 24 h following HCG injections, activity accounted for 67% and 45% of the total activity in no shelter treatment for females and males, respectively, in comparison with 77% and 78% in shelter treatment. Activity was significantly more pronounced during this phase than during other phases for each sex in either shelter treatment. Egg release and sperm ejection occurred in the water column around the time eels' activity reached peaks. Eels either returned into the shelters or stayed motionlessly on the bottom of the aquaria after egg release and sperm ejection. Eight out of nine (89%) females in no shelter treatment spontaneously released eggs with a total of 11 batches 14-18 h following HCG injections, in contrast with four out of nine (44%) females releasing eggs for 4 batches 16-20 h in shelter treatment. Males arrived at activity peaks 11-13 h following HCG injections in no shelter treatment, 2-4 h ahead of the females (14-16 h), in comparison with 8-11 h in shelter treatment with 5-6 h ahead of the females (14-17 h). Courtship behavior indicative of spawning such as pairing, chasing and touching bodies was not observed in the eels in this study. However, on many occasions, eels of both sexes (male-female or female-female) were found to "cruise together" in water column for a short time period or frequently come together prior to releasing eggs and ejecting sperm, suggesting the possibility of group mating in artificially matured Japanese eels. (c) 2007 Elsevier B.V. All rights reserved.

Temperature influence on the spawning performance of artificially-matured Japanese eel, Anguilla japonica, in captivity

We studied the influence of temperature on the spawning performance of artificially matured Japanese eels, Anguilla japonica, in captivity. We used routine hormone injections to bring females and males to maturity in separate aquaria. We recorded the behavior of three pairs of such hormone-treated matured eels in an aquarium (2 replicates) at four temperatures: 14, 18, 22, and 27 degrees C, respectively. They became active and frequently left the bottom swimming in the water column, and spawning events occurred. Females released eggs in the water column around the activity peaks. Males preceded females in reaching activity peaks (presumably the timing of sperm ejection and egg release), possibly resulting in the low fertilization we observed in this experiment. Males and females returned back to the aquarium bottoms and became quiet after spawning. On several occasions, male-female or female-female pairs were observed to 'cruise together' in the water column for several to tens of seconds prior to egg releasing, but no courtship behavior indicative of spawning such as pairing and chasing was observed in the eels in our study. Our results suggest that 18-22 degrees C might be the thermal preference for spawning for Japanese eels, which approximates the temperature range of the 500 m deep water layer around the Mariana Islands seamount area, the presumed spawning site for the Japanese eel.

Divergent selection and realized heritability for growth in the Japanese scallop, Patinopecten yessoensis Jay

In order to improve the production and accurately estimate response to selection, divergent selection for growth in shell height was conducted in a cultured population of the Japanese scallop Patinopecten yessoensis. Applying the same selection intensity +/- 1.756 in upward and downward directions, three groups including two selected groups of Fast and Slow and one non-selected Control group were created, which were reared under the same environmental conditions at any stage. Differences always significantly existed among the three groups (P < 0.05), except for larvae at day 1 and at day 5, and in the order of Fast > Control > Slow. The average standardized response to selection (SR), realized heritability (h(R)2) and genetic gain (GG) was 0.473%, 0.269% and 7.85% for the Fast group and 0.381%, 0.217% and 6.60% for the Slow group respectively. Moreover, significant differences (P < 0.05) were detected between the fast and the slow lines in both SR and h(R)2, providing evidence for an asymmetric response in two directions. Performance in shell height is improved by 7.85% in the fast line after one generation selection, suggesting that mass selection for faster growth in a cultured population of the Japanese scallop is effective.

Japanese women speak : a message from the Christian women of Japan to the Christian women of America / by Michi Kawai, Ochimi Kubushiro ; cover design and frontispiece by the Japanese artist Rokuyåo.

http://www.archive.org/details/japanesewomenspe032256mbp

序破急 Jo-Ha-Kyu: enticement - crux - consolidation. From study to learning: Process drama projects in the Japanese English language university classroom

This dissertation investigates how social issues can be explored through process drama projects in the Japanese university English as a Foreign Language classroom context. The trajectory of this dissertation moves along a traditional Noh three part macro-continuum, called Jo-Ha-Kyu, interpreted as enticement, crux and consolidation. Within these three parts, there are six further divisions. Part I consists of three sections: Section I, the introduction, sets the backdrop for the entire dissertation, that of Japan, and aims to draw the reader into its culturally unique and specific world. This section outlines the rationale for placing the ethnographer at the centre of the research, and presents Japan through the eyes of the writer. Section II outlines relevant Japanese cultural norms, mores and values, the English educational landscape of Japan and an overview of theatre in Japan and its possible influences on the Japanese university student today. Section III provides three literature reviews: second language acquisition, drama in education to process drama, and Content Language Integrated Learning. In Part 2, Sections IV and V respectively consist of the research methodology and the action research at the core of this dissertation. Section IV describes the case of Kwansei Gakuin University, then explains the design of the process drama curricula. Section V details the three-process drama projects based around the three social issues at the centre of this dissertation. There is also a description of an extra project that of the guest lecturer project. The ultimate goals of all four projects were to change motivation through English in a CLIL context, to develop linguistic spontaneity and to deepen emotional engagement with the themes. Part 3 serves to reflect upon the viability of using process drama in the Japanese university curriculum, and to critically self-reflect on the project as a whole.

Quantifiable biomarkers of normal aging in the Japanese medaka fish (Oryzias latipes).

BACKGROUND: Small laboratory fish share many anatomical and histological characteristics with other vertebrates, yet can be maintained in large numbers at low cost for lifetime studies. Here we characterize biomarkers associated with normal aging in the Japanese medaka (Oryzias latipes), a species that has been widely used in toxicology studies and has potential utility as a model organism for experimental aging research. PRINCIPAL FINDINGS: The median lifespan of medaka was approximately 22 months under laboratory conditions. We performed quantitative histological analysis of tissues from age-grouped individuals representing young adults (6 months old), mature adults (16 months old), and adults that had survived beyond the median lifespan (24 months). Livers of 24-month old individuals showed extensive morphologic changes, including spongiosis hepatis, steatosis, ballooning degeneration, inflammation, and nuclear pyknosis. There were also phagolysosomes, vacuoles, and residual bodies in parenchymal cells and congestion of sinusoidal vessels. Livers of aged individuals were characterized by increases in lipofuscin deposits and in the number of TUNEL-positive apoptotic cells. Some of these degenerative characteristics were seen, to a lesser extent, in the livers of 16-month old individuals, but not in 6-month old individuals. The basal layer of the dermis showed an age-dependent decline in the number of dividing cells and an increase in senescence-associated β-galactosidase. The hearts of aged individuals were characterized by fibrosis and lipofuscin deposition. There was also a loss of pigmented cells from the retinal epithelium. By contrast, age-associated changes were not apparent in skeletal muscle, the ocular lens, or the brain. SIGNIFICANCE: The results provide a set of markers that can be used to trace the process of normal tissue aging in medaka and to evaluate the effect of environmental stressors.

Development of hemispheric specialization for lexical pitch-accent in Japanese infants.

Infants' speech perception abilities change through the first year of life, from broad sensitivity to a wide range of speech contrasts to becoming more finely attuned to their native language. What remains unclear, however, is how this perceptual change relates to brain responses to native language contrasts in terms of the functional specialization of the left and right hemispheres. Here, to elucidate the developmental changes in functional lateralization accompanying this perceptual change, we conducted two experiments on Japanese infants using Japanese lexical pitch-accent, which changes word meanings with the pitch pattern within words. In the first behavioral experiment, using visual habituation, we confirmed that infants at both 4 and 10 months have sensitivities to the lexical pitch-accent pattern change embedded in disyllabic words. In the second experiment, near-infrared spectroscopy was used to measure cortical hemodynamic responses in the left and right hemispheres to the same lexical pitch-accent pattern changes and their pure tone counterparts. We found that brain responses to the pitch change within words differed between 4- and 10-month-old infants in terms of functional lateralization: Left hemisphere dominance for the perception of the pitch change embedded in words was seen only in the 10-month-olds. These results suggest that the perceptual change in Japanese lexical pitch-accent may be related to a shift in functional lateralization from bilateral to left hemisphere dominance.

Japanese language teaching: a communicative approach

Japanese Language Teaching examines the practical aspects of the acquisition of Japanese as a second language, underpinned by current theory and research. Each chapter examines the theory and practice of language teaching, and progresses to a consideration of the practical design of tasks for teaching. The final section applies theory and practice to an empirical case study, drawn from a classroom with Japanese as a second language. With its emphasis on practice underpinned by contemporary theory, this book will be of interest to postgraduates studying second language acquisition and applied linguistics. [Source: publisher's description].