When to swordfish in the grand banks?

"Around level 60, fishing for them at 50 can be slow and unrewarding." Personally I think at level 65. At this level, you're allowed to use Fist of Guthix sWordfish gloves, and they give you an additional 100 xp per sWordfish. Only with these gloves does fishing for sWordies outweigh lobster caging, because of the frequency of tuna.