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381.
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
382.
We estimated the stock size of Japanese sardine ( Sardinops melanostictus ) in the Sea of Japan and East China Sea since 1953 using cohort analysis based on the changes of growth patterns. Growth of Japanese sardine, estimated by using annual rings on archived scales since 1961, showed that body lengths were extremely stunted in the 1980–1987 year-classes. The body length at age 3 from February to April in the 1980–1987 year-classes, a period when the stock size exceeded 4 million tons, was 180.0 ± 2.6 mm (mean ± SD), and in the other year-classes was 195.1 ± 7.6 mm. The body length at age 3 and wet weight of zooplankton in August in the offshore area of the Sea of Japan had a significantly positive correlation. We assumed three scenarios for maturation ratios, and estimated Ricker's spawner–recruitment relationships. We analyzed the correlations between logarithmic recruitment residuals (LNRR) and environmental factors in winter, represented by the North Pacific index (NPI), Aleutian low pressure index (ALPI), Pacific decadal oscillation (PDO), monsoon index (MOI), Arctic oscillation (AO) and Southern oscillation index (SOI). Significant correlations were observed between MOI and LNRR and between AO and LNRR. A combination of strong MOI and weak AO would increase the biomass of phytoplankton and zooplankton and subsequently increase the recruitment of Japanese sardine. 相似文献
383.
We investigated the effect of poultry manure (PM) on the occurrence and early growth of Monochoria vaginalis in relation to soil solution electrical conductivity (SSEC). PM was applied at rates corresponding to 0 g of nitrogen (N) m?2 (PM-0), 1 g N m?2 (PM-1), 3 g N m?2 (PM-3), and 5 g N m?2 (PM-5). At 7 d post-seeding, the soil solution was sampled to measure EC, and also the emergence and growth of M. vaginalis were evaluated. The emergence rate of M. vaginalis decreased with increasing application rate of PM and SSEC. SSEC was significantly negatively correlated with the emergence rate of M. vaginalis seedlings. The average leaf number and length of M. vaginalis did not differ between PM-0, PM-1, and PM-3, but were significantly lower in PM-5. In summary, PM would allow to better control the emergence and early growth of M. vaginalis. 相似文献
384.
385.