| a regional survey of malformed frogs in minnesota (usa) (minnesota malformed frogs). | in late 1995, school children discovered malformed frogs in a south central minnesota pond. press coverage resulted in numerous citizen reports of frog malformation across minnesota in 1996. after some initial site investigation, 3 affected frog sites and 4 nearby reference sites were selected for more detailed evaluation. field biologists made 89 visits to study sites beginning spring 1997 through fall 1999 to examine the number and type of frog malformations. over 5,100 leopard frogs (rana pip ... | 2003 | 12602621 |
| prevalence of skeletal and eye malformations in frogs from north-central united states: estimations based on collections from randomly selected sites. | skeletal malformation rates for several frog species were determined in a set of randomly selected wetlands in the north-central usa over three consecutive years. in 1998, 62 sites yielded 389 metamorphic frogs, nine (2.3%) of which had skeletal or eye malformations. a subset of the original sites was surveyed in the following 2 yr. in 1999, 1,085 metamorphic frogs were collected from 36 sites and 17 (1.6%) had skeletal or eye malformations, while in 2000, examination of 1,131 metamorphs yielded ... | 2003 | 14567211 |