Is a thinning ozone layer causing a decline in the number of  frogs?  Well for years, some activists have been croaking about  just such a connection by stating that increased levels of uv-b  radiation caused by a thinning ozone layer are roasting the  amphibians eggs in shallow ponds.  But now comes a new report by  the University of Washington that challenges that assertion.  The  study looked at 136 breeding sites in the Olympic and Cascade  mountains and found that levels of organic matter present in the  water which absorb uv-b radiation and shield vulnerable eggs were  sufficiently high to protect 85 percent of the amphibians habitat.  So it looks like, once again, some have leaped to wrong conclusions  about ozone and frogs.