CONTENTS Introduction Page Materials and Methods Results Trends or Decline in the Levels of Radioactivity Variation in the Samples Comparison of the Decline of Radioactivity by Species 14 Comparison of the Decline of Radioactivity in Fish with that of their Food and with Other Factors 14 Comparison of Decline with Decay of Radioactivity 20 Conclusions ot References 2g Appendix 31