Hooked a Whaler, eaten by a Mako, eaten by something else...
https://www.cnn.com/2019/03/29/australia/australia-shark-fisherman-scli-intl/index.html
They never say how long it was on the line. It looks like a long line or drum line and if so the shark could have been there long enough to die or at least worn out to the point it couldn't swim and anything with teeth could eat it at that point. Even a school of dog fish.