PRE-1900 OVERHARVEST OF CALIFORNIA RED-LEGGED FROGS (RANA AURORA DRAYTONII): THE INDUCEMENT FOR BULLFROG (RANA CATESBEIANA) INTRODUCTION

Pre-1900 frog harvest data from California suggests heavy exploitation of California red-legged frogs (Rana aurora draytonii). A comparison with data collected from present-day, non-exploited, healthy populations of R. a. draytonii suggest that mostly female frogs may have been harvested. A low reproductive frequency and the probable female frog harvest bias suggest that historical populations could not withstand harvest at pre-1900 levels. The decline in frog harvest observed from 1899-1940 supports this idea. Population depletion and a persisting demand for frogs were probably the inducements to import and introduce bullfrogs (Rana catesbeiana). The earliest dates of bullfrog introduction correspond well with these suppositions.