A mate of mine hooked up to a 5 footer on some relatively light tackle. These things could easily take a limb at that size. Fish was taken 50km upstream and they'll definitely go up further. Now, let's all go swimming.
Pete the fish was taken on a 30cm Bream. Might be a helpful tip for next time :P . Though somehow I don't think too many 5 footers will be venturing up your thin blue line. Won't get too many Jacks on that bait either, haha.
Troy
http://au.youtube.com/watch?v=AugGzmKUlo8