ABSTRACT. To study the effect of estrogenic chemicals on fish, the gonadosomatic index (GSI = [testis weight/body weight] × 100) and testis histology of mature common carp (Cyprinus carpio) from 2 contaminated sites (Ishizu and Wada rivers, Osaka) and a control site were examined between June 1998 and March 2001. The concentration of nonylphenol, bisphenol A and 17β-estradiol in the Ishizu river was 3-4 times higher than in the Wada river. In the pre-breeding and breeding seasons, there were no significant differences in body weight among carp from the 3 sites, the body weight of Ishizu river carp being significantly lower (p<0.05) than that of Wada river fish only in the post-breeding season. The GSI and testis weight in fish from the Ishizu river were significantly lower (p<0.05) than in control fish during all phases of gonadal cycle and lower than in Wada river fish in the pre-breeding and post-breeding season. No histological abnormalities were found in the testes of the males examined. Histological observation of the testes revealed a delay in the onset of spermatogenesis in fish from the Ishizu river compared with those from the other sites. These results clearly imply that the estrogenic chemicals in the Ishizu river adversely affect the testis development of the fish. There is growing evidence in support of the claim that contamination of a wildlife population with estrogenic chemicals can disturb the reproductive function of vertebrates [6,7,12]. Many researches have been focused on fish, since as aquatic inhabitants they receive sewage or industrial effluent and agricultural runoff containing estrogenic chemicals [5,14,30]. In fish, estrogenic responses have been associated with exposure to pesticides [3,35], pulp mill effluents [23,29,34], plasticizers [19] and sewage effluent [2,17,31]. Abnormalities have also been reported in the male reproductive system of fish living in water polluted by sewage or industrial chemicals [12,25]. Studies on the male teleost revealed changes including induced vitellogenin production [5,13,14,20], hermaphroditism as evidenced by the presence of both testicular and ovarian tissues [8,10,11,18,31], reduced testis size [20] and reduced plasma androgen concentrations together with delayed sexual maturity [26].Some information is known on the effect of estrogens and estrogenic chemicals on the carp testis, and their relation to seasonal changes in testis morphology. Three-month exposure to a sublethal dose of 4-tert-pentylphenol or 17β-estradiol causes progressive disappearance of spermatozoa and spermatogenic cysts, and reduces the seminiferous tubule diameter, in mature male carp [11]. Ovo-testes were found in juvenile carp exposed to xeno-estrogens during sexual differentiation [8,9]. However, a field study on adult crucian carp (Carassius carassius) living in a pond containing treated pulp mill effluent showed no gonadal deformation or feminization of male gonads [23]. It is therefore important to study the testis of mature male carp (Cyprinus carpio) living in rivers ...

ABSTRACT. The adverse effect of estrogenic chemicals on luteinizing hormone-immunoreactive (LH-ir) cells in the adenohypophysis of common carp (Cyprinus carpio) was examined using immunocytochemical and morphometric methods. Adult male fish were collected from two contaminated sites (Ishizu and Wada Rivers) and from a control pond at Agriculture, Food and Environmental Sciences, Research Center of Osaka Prefecture. The concentration of nonylphenol, bisphenol A and 17 β-estradiol in the Ishizu River was 3-4 times higher than that in the Wada River. The proportion and size of LH-ir cells were evaluated using the point-counting method by optical microscopy. In control carp, the proportion of LH-ir cells in the breeding season was significantly lower than in the pre-and post-breeding seasons. The same tendency was also found in Ishizu and Wada River carp, but without statistical significance. T he proportion of LH-ir cells in Ishizu River carp was significantly lower than that of the control and the Wada River in all seasons. The LHir cells in control carp increased in size in the breeding season. LH-ir cells in Ishizu River carp were significantly (p<0.05) smaller than those in control fish, but not different from Wada River carp. A disturbance in the secretory function of LH-ir cells was found in carp from the Ishizu River; granulation and vacuolation were not in synchronization with those of control and Wada River fish. Our data suggest that the estrogenic chemicals in the Ishizu River interfere with functions of LH-ir cells directly or through the testis.

The hypothesis that the Ajime-loach, Niwaella delicata, is guided to groundwater seepages by a positive thermotaxis in autumn, was tested by a fi eld investigation and aquarium-based experiments. A total of 763 individuals of N. delicata were captured from October to November in a groundwater trap in the Yasu River, Shiga Prefecture. Niwaella delicata began to be captured as the temperature of the surface water fell to 15.8° ± 1.1°C (mean ± SD) and that of the groundwater to 15.5° ± 0.9°C. Groundwater was often warmer than surface water at night or occasionally all day, and the difference in temperature reached a maximum of 1.3°C at the night on 5 November. For the diel pattern of captures, nocturnal capture was higher than diurnal capture when the groundwater was warmer at night and colder during the daytime, whereas both diurnal and nocturnal captures were high when the groundwater was always warmer than the surface water. The aquarium-based experiments showed that N. delicata choose warmer water, ranging from 18.4° to 22.2°C, just before the capture period in the Yasu River, and are sensitive to differences in water temperature of 1.3° ± 0.1°C. Although the present results broadly support the hypothesis, a part of the results indicates that water temperature gradients may not be the only factor involved in the groundwater selection of N. delicata.

Developmental Changes in 'Delaware' due to Climate Change in Osaka study on 'Delaware' grape.'Delaware' grape (Vitis labruscana Bailey) is a table grape cultivar that has the third largest growing area in Japan. Moreover, in Osaka Prefecture in the Kansai region of Japan, 'Delaware' is the main cultivar that accounts for 80% (266.7 ha) of grape production (Ministry of Agriculture, Forestry and Fisheries 2018). We previously confirmed that 'Delaware' grape, under open field conditions in Osaka, showed accelerations in budding and full-flowering from 1963 to 2010 (Kamimori et al. 2019) and statistically modeled the relationships between the budding and full-flowering dates and air temperature using data collected over nearly 50 years (Kamimori et al. 2020). The budding and full-flowering dates are indicators of the timing of cultivation management practices, such as pest control, shoot treatment, and gibberellic acid application. Grape growers combine different cropping types or varieties to shift the budding and full-flowering date, when cultivation management