Dunno much about shark, but for halibut, you wanna find a place where the bottom has some nice humps, sometimes if you find a tall stand of kelp, there will be a hump down at the bottom. They like to sit right on top. My old rig was a three-eyed swivel, then under the swivel, I'd use about two feet of line then a heavy jig head or swimbait (used basically just like a heavy sinker), then off the other leg, I'd use about four feet of line with, (I think they're called
a spin-killer. It's a little plastic clip that you put on an anchovy's nose and it causes it to whirl like it's injured and it's got a big circle hook that dangles right next to the fish.
Now I work on a tugboat in Alaska and I've been learning different techniques from the guys up there. They don't use that rig, but just a great big hook with a big chunk of squid on it and a four pound lead weight about three feet from the hook.
I've also had a little luck with a herring-jig. I got a nice light-action rod and I use a one ounce jig. Drop it to the bottom, then bounce it up and down from about one foot off the bottom to about four feet off the bottom. Just let it drift down and then flick it back up.
Fishing in Alaska is a whole different story from down here. We got this beauty right before I came home from work three weeks ago. I kinda can't wait to go back:
That's a 170 lb. fish. We had to put the rescue boat in the water to get that thing on board. And you know what? The meat is just as good on the big ones.