The New Jersey black bear (Ursus americanus) population has been growing rapidly in both distribution and abundance in recent years (Carr and Burguess 2005). Although fewer than 100 bears, restricted to the northern most part, are thought to have been present in the state in the 1950s, by 2001, the population was estimated at 1,777 in northern New Jersey and the range had expanded to occupy roughly the western two-thirds of the state. This is believed to be a consequence of protection afforded by game-animal status, which was conferred on bears in 1953, and of the maturation of young forests in the state, leading to improved habitat and food supply (e.g., hard mast). Natural food is supplemented by food of human origin, such as garbage and agricultural crops. The expanding bear population has led to an increasing number of conflicts with humans in New Jersey.

The New Jersey Department of Environmental Protection, Division of Fish and Wildlife, has regulatory authority for managing the state’s bear population. Hunting, which can both control numbers and result in aversive conditioning of bears (Geist 2005), has become controversial. Better management of garbage, bird feeders, and other bear attractants could help to reduce human-bear conflicts. However, conflicts are bound to increase if the bear population continues to expand. In 2004, United States state wildlife agencies reported a perceived 45 % increase in expenditures to control bear-related damage, a 22 % increase in personnel-hours to resolve bear-related complaints, and a 19 % increase in the overall number of complaints over the previous 5 years (International Association of Fish and Wildlife Agencies 2004).

The size of a wildlife population is governed by just 4 basic factors: 1) fertility, 2) mortality, 3) emigration, and 4) immigration. Emigration and immigration are difficult to control and have little potential as tools to affect bear populations in a particular area, although the removal and long-distance displacement of individual problem bears is a common practice in many jurisdictions. Mortality and fertility can potentially be manipulated to affect the size of particular populations. In the past, the size of game animal populations, has been managed largely by adjusting the harvest, and a large body of information about this approach has developed over the years. On the other hand, over the past 25 years, managing wildlife populations by controlling fertility has been a focus of considerable interest (Fagerstone 2002). Despite this interest, however, fertility control (FC) has been applied in few situations, so little practical experience exists – none of it involving bears.

The following conclusions were reported by the Principal Investigator based on the literature review and assessment of the Feasibility of Fertility Control of the Black Bear Population: