Hey I was just thinking today that those people who use gopros to film fishing must have a way to keep it charged for hours any body know how to do this?

I use a Garmin Virb.  It films for 6 hours on a single charge.

I have a Garmin Virb Elite but I use a 12V adapter and plug it into my boats cigarette lighter. 

They carry extra batteries

have any of you guys used the ion cams? looking at getting one..

another possible way is keep extra battery packs with you if the cam can charge while recording