The effects of bis(tributyltin) oxide on the development, reproduction and sex ratio of calanoid copepod Pseudodiaptomus marinus

In order to study the biological effects by bis(tributyltin) oxide (TBTO) exposure, chronic toxicity tests were conducted on the calanoid copepod Pseudodiaptomus marinus over two generations. The results indicated that nauplii were more sensitive than copepodites. F1 copepods were more vulnerable than F0 copepods and a drastic increase in mortality was observed as the TBTO concentration became higher. Exposure of copepods to 60 ng l 1 TBTO concentration reduced the fecundity and resulted in some females being infecund (in the F0 generation). The time to the first egg sac for females in the F1 generation exposed to 6 ng l 1 TBTO concentration was significantly reduced, and the fecundity of this generation was increased. The female-to-male ratio in the F1 generation exposed to 20 ng l 1 TBTO concentration was significantly reduced. These results show that the current ambient TBT concentration may influence populations of copepods in the coastal environment.