The water around the very tip of the parks can experience some strange currents. Bear in mind the safety signs there, they are in place for a reason. Also be aware of the E.Coli count in the park's waters. A minor annoyance is the presence of ticks and poison ivy, though this can be avoided by generally staying on marked paths which you should do anyway. Besides this park is a safe place, there are not even concerns over dangerous animals as you would expect in many other national parks.
fees/permits
Standard Parks Canada prices will apply, though these vary park to park and by season. The annual national parks pass is recognized here.