|Garber, E - FORMERLY 5442-05-05|
|Gackle, N - NORTH DAKOTA STATE UNIV|
|Canfield, J - MPCA|
Submitted to: Minnesota Water Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: January 1, 2002
Publication Date: April 17, 2002
Citation: Shappell, N.W., Garber, E.A., Gackle, N.J., Canfield, J., Larsen, G.L. 2002. Malformation versus mortality, a study of northern leopard frog development in situ. [abstract]. Minnesota Water 2002 Conference, April 17-20, 2002, St. Cloud, MN. Technical Abstract: Field studies were designed to compare the relative incidence of mortality and malformation of developing northern leopard frogs (Rana pipiens) at two Minnesota (MN)Lake sites. Site selection was based on survey data that indicated one site had a high incidence of malformations (CWB) versus low incidence at the second site (BUT) and similar topographical and hydrological characteristics. Four clutches of healthy tadpoles (stage 26) were collected from a manmade pond in North Dakota (ND) with no history of malformations. Two large aluminum enclosures were placed at each site, one with larvae receiving supplemental feed and the second no supplemental feed. Each large enclosure housed 4 baskets containing 65 larvae each (one each from clutch land 4, and two from clutch 3). Clutch 4 and extra larvae from clutches 3 and 4 were maintained in the laboratory in the original ND site water changed every other day. Sites were visited 3-5 times per week to assess tadpole mortality, monitor water conditions, and maintain food supply. After two weeks, significant mortality began to occur at both sites, while no mortality was exhibited by larvae in the laboratory. At this point an enclosure containing larvae being held in the lab were placed at the ND source pond. Co-incubation of larvae from the BUT site with healthy larvae in the lab resulted in mortality, while no mortality was found in those from CWB. From the second to fourth week mortality ranged from 37% to 85% for both MN sites, while no mortality was seen in the labor ND pond. Only one larvae surviving to metamorphosis exhibited malformation (not includingis scoliosis, which was seen in the lab at a similar incidence). Water from the ND pond, BUT and CWB were analyzed using the Frog Embryo Teratogenesis Assay - Xenopus (FETAX).