That low? Well, I stand corrected. In that case, the 0.8J plug in should be adequate..7-1 joules minimum is recommended to stop bears. http://www.bearsmart.com/docs/MFWP-ElectricFenceGuideBears.pdf
The ones sold at tractor supply do not indicate they are for large species until you get into the J range of mine, or "larger/longer" rated fences.