For most private docs, a minimum is 12 12 hour shifts a month. This is extremely variable with groups working a variety of 8, 10 or 12 hour shifts, most work more than this. This does not account for outside meetings etc. Keep in mind this is usually a mix of days/evenings/nights, weekends and holidays.
I'm not sure what typical academics work.
Fellowship salaries are usually posted for whatever program you are interested. Keep in mind when looking at them, the higher salaried ones usually require you to pull shifts in the ER in addition to whatever fellowship requirements there are.