Embryo mortality relative to the abundance category of the water mold, Saprolegnia diclina, and an unidentified predatory flatworm (Turbellaria spp.) for egg masses of Anaxyrus canorus at various breeding sites near Tioga Pass, California, USA, in 2001

We produced this data set as part of a larger, integrated study to assess the statuses of populations of Anaxyrus canorus and the causes of observed effects on fitness at field sites, primarily in Yosemite National Park near Tioga Pass, from 1996 to 2001. To assess embryo mortality, we visually evaluated each individual embryo in an egg mass in situ while kneeling alongside it immediately before, at, or very soon after hatching (when individual capsules remained from hatched embryos and when any remnants of dead embryos typically still were visible). We did not assess mortality in any egg masses that had deteriorated too far to evaluate embryos. In 2001, a limited number of field personnel caused us to estimate the proportion dead [...]