抄録
Sea urchins (fully mature: large, mature: medium and maturing: small) were cultured for 2 weeks in seawater containing nonylphenol (NP). The GT ratio (=100·gonad volume/test volume) was measured for all sea urchin samples that were then classified into five ranks. The grade of maturity of sea urchin gonads was also determined. The graded sea urchin gonads were fixed, sectioned and stained for microscopic observations. The results were compared in terms of size, sex and NP treatment concentration. The average GT ratio decreased with decreasing size, whereas it increased with increasing NP treatment concentrations. The grade of maturity was V or IV in large and medium female and male (probably) sea urchins in the control and treatment groups. The grade was under III in small ones ; the same result for both sexes was observed. On microscopic observation, the acceleration of gametogenesis was observed in treated sea urchins. Hermaphrodite (testis-ova) urchins were also observed.
