Life History And The Toxicity Sensitivity In Sediment Of The Benthic Amphipod Grandidierella Japonica (Second Generation)

Sediment toxicity tests are a critical component in many programs to assess environmental quality. There has been a substantial increase in research and regulatory activity to assess contaminant sediment. However, only a few test species are available. Therefore, it is necessary to develop bioassay testing protocols and testing organisms for the quantitative assessment of contaminant sediment.Amphipods are ecologically important members of benthic infaunal communities and are one of the most sensitive members among benthic communities to anthropogenic disturbance, including pollution. Grandidierella japonica in this study is a corophiid amphipod species, builds a U-shaped tube in sediments ranging from coarse sand to silty clay in the intertidal zone.We study and master the second generation of life history of marine amphipod G japonica, compare the toxicity sensitivity in each phase of whole life among wild and second generation populations. This study will lay a foundation for testing species culturing more in laboratory and using widely, the achievements will promote biological testing work run as routinely in China.Our objectives were to (a) establish cultures in Lab. (b)conduct life-cycle and reproduction-cycle test (c) determine survival, sex ratio and hatching ratio of second generation life stages through life history test. G japonica was held in the lab for reproducing less 5 times and had high survival in preliminary culture. Juveniles were first produced at 38d at 20℃ and at 22d at room temperature. Females generally relieved juveniles 28-41. The sex ratio of juveniles was approximately one to one. Males survive time short than females.The water-only toxicity tests have demonstrated that mortality of G japonica is positive correlated with concentration of cadmium, and this species is sensitive to mental cadmium. One-week juveniles is more sensitive to cadmium than two-week and three-week juveniles, and to a lesser extent four-week juveniles. Considering life history, this study concluded two-week and three-week juveniles were amenable to the toxicity test. Sensitivity of lab cultured G japonica of second generation wascomparable to that of field collected Gjaponica in toxicity test. Field collected Gjaponica was more sensitive than lab cultured.The 10-d sediment toxicity test has been developed with cadmium-spiked sediment using two-week juveniles of lab cultured F2 and field collected in 20°C .When SEM/AVS surpassed 1.6, the mortality of G japonica was 100%.There has been no significant toxicity happened on SEM/AVS less l.O.The trend of mortality of G japonica in 10-d sediment was coincident with the effect of assessment with SEM/AVS model.Results from a variety of experiments indicated that G japonica has a relatively short generation time and is amenable to laboratory cultured. In addition, G japonica is sensitive to cadmium-spiked sediment. In conclusion, G japonica from lab culture is a desirable attribute for sediment testing species as well as that of field collect.