These data have been collected annually from State Wildlife Agencies by the U.S. Furbearer Conservation Technical Work Group of the Association of Fish and Wildlife Agencies, and from Provincial Agencies by Statistics Canada. Fur harvest data sources varied between agencies and years. Sources of information included fur buyer, fur dealer, and fur trapper reports. In some states/provinces, pelt tagging records and periodic trapper questionnaires were also utilized. For most species, the harvest data presented are largely trapper harvest and should be considered a minimum harvest. In some seasons for a particular state/province there was no data received, but does not necessarily mean there was no harvest. Therefore, a zero value can refer to no harvest or no data available.
The number of animals harvested is indicative of population trends if harvest effort is relatively constant (number of licenses issued and trapping effort), but can be misleading if harvest effort is not constant over time (i.e. decrease in harvest effort over time). There are many factors that can influence furbearer harvest. Some of these factors include changes in market demands, natural cyclic fluctuations in populations, weather conditions for trapping, changes in timing of trapping seasons, changes in types of traps allowed, and changes in trapping participation levels.