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261.
Stock size fluctuations in chub mackerel (Scomber japonicus) in the East China Sea and the Japan/East Sea 总被引:3,自引:0,他引:3
The stock size of chub mackerel (Scomber japonicus) in the East China Sea and the Japan/East Sea has shown a continuous decrease, with fluctuations, from 1975 to 1990. After a remarkable increase in 1992–96, the stock size fell to its lowest level in 1997–99. The spawning success (number of recruits/spawning biomass) fluctuates periodically with a period of several years, although there are no clear relationships between the spawning biomass and the number of recruits. Spawning success was inversely correlated with sea surface temperature (SST). On the contrary, the catch amount and the catch per unit effort (CPUE) of spotted mackerel (Scomber australasicus) has increased since 1997. 相似文献
262.
Seiji Ohshimo Mari Yoda Nobuaki Itasaka Norimasa Morinaga Toshio Ichimaru 《Fisheries Science》2006,72(4):855-859
ABSTRACT: The purpose of this study was to determine the growth and reproductive characteristics of round scad Decapterus maruadsi in the East China Sea. The characteristics regarding growth and reproduction of round scad based on otolith reading and gonad histology, respectively, were estimated. The von Bertalanffy's growth model for round scad was estimated as follows:
FL t = 342[1 − exp{−0.55( t + 0.58)}], (1 < t < 7)
where FL t is fork length (mm) at age in years t . The maturation stage of the ovary was observed by histological techniques. June was the main spawning period; the maturation and migratory nucleus stage of the oocyte was observed when the gonad somatic index value was approximately greater than 4. 相似文献
FL
where FL
263.
264.
Murase K Shiba H Iwano M Che FS Watanabe M Isogai A Takayama S 《Science (New York, N.Y.)》2004,303(5663):1516-1519
Self-incompatibility (SI) response in Brassica is initiated by haplotype-specific interactions between the pollen-borne ligand S locus protein 11/SCR and its stigmatic S receptor kinase, SRK. This binding induces autophosphorylation of SRK, which is then thought to trigger a signaling cascade that leads to self-pollen rejection. A recessive mutation of the modifier (m) gene eliminates the SI response in stigma. Positional cloning of M has revealed that it encodes a membrane-anchored cytoplasmic serine/threonine protein kinase, designated M locus protein kinase (MLPK). Transient expression of MLPK restores the ability of mm papilla cells to reject self-pollen, suggesting that MLPK is a positive mediator of Brassica SI signaling. 相似文献
265.
Journal of General Plant Pathology - A new disease on celery discovered in Japan caused extreme stunting, dwarfed and yellowed leaves, black rot of the celery “heart”, and root rot. A... 相似文献
266.
Toshikazu Yano Tsutomu Hattori Tsuneshiro Tamukai Seiji Ohshimo 《Fisheries Science》2017,83(6):917-928
The present study elucidated the length structure and habitat segregation of North Pacific spiny dogfish (SPD) Squalus suckleyi in the Tsugaru Strait of northern Japan. Length–frequency distributions using kernel density estimation were determined for SPD captured by the bottom longline fishery landed at Minmaya from 1999 to 2011 and at Ohma from 2007 to 2011. Length–frequency distributions significantly differed between landings at the two ports; SPD at Minmaya were on average larger (65–85 cm precaudal length: PCL) than at Ohma (55–75 cm PCL). This difference is evidence of the length-based spatial segregation of the SPD. The seasonal landing pattern of the SPD was also different between the two ports. The SPD landed at Minmaya were largest during February–June and SPD < 75 cm PCL were caught at Ohma throughout the year. This different landing pattern was related to seasonal differences in bottom-layer water temperatures between the two fishing grounds. Females were thought to be dominant at Minmaya, whereas males dominated in most of the catches at Ohma. These results suggest spatial patterns of sexual segregation for this species in the Tsugaru Strait and require elucidation of the SPD stock condition at Minmaya and Ohma. 相似文献
267.
The growth and mortality of Neptunea arthritica juveniles hatched from different egg masses (controlled conditions and field) reared at 10 and 15 °C, and provided with sardine (D1) and polychaete (D2) as foods were evaluated. Results showed that diet type and water temperature significantly affect the growth and mortality. Interaction between these factors reflected robust relationship among them, but restricted exclusively to growth. Through the study period, juveniles treated at 10 °C showed maximum increments of 2.5 mm (shell length), 2.3 mm (shell width) and 0.25 g (body weight) from their initial size. While maximum values of those treated at 15 °C for the above-mentioned parameters were 7.6 mm, 5.5 mm and 1 g respectively. In both cases, these increments were recorded for individuals fed with sardine. Mortality was significantly affected by diets and water temperature, which significantly increased under D2 [10 °C (20–67%), 15 °C (70–87%)] or 15 °C [D1 (30–83%), D2 (70–87%)]. According to the results, juveniles of N. arthritica could be maintained under controlled conditions, which allows growth improvement. Mortality appears to be the limiting factor, but this could be improved by the implementation of efficient culture method, basically oriented to increase the water quality. 相似文献
268.
In order to verify which factors affect habitat selection for aestivating and in the active adult Apostichopus japonicus, animals were tested for their selection of attachment site in an experimental device (1-m pipes) in which the perceived
environmental stimuli (light intensity, degree of contact with a hard surface, geotaxis) varied depending on the attachment
site. During the aestivating season, the animals showed a strong selection for attachment sites during the daytime and nighttime;
they also showed positive stereotaxis (thigmotaxis), negative phototaxis, and negative geotaxis. The results suggest that
(1) habitats are not suitable for the aestivating adult A. japonicus unless these three environmental requirements are satisfied. 相似文献