A guide buddy of mine in Ak. (who shall remain anonamous for obvious reasons) took out a big bull sealion with a seal bomb and a gaff this summer.
He was fishing a real popular "big king" spot that has had 1 particular big bull in there for a few years that has taken alot of kings, he is (was)very stealthy, you usually didn't know he was there till he had your fish. Anyways, this 1 afternoon in late July this guide had hooked a couple fish and lost 1 to mr. sealion, his 3rd fish was close to 40 lbs. and about 10 ft. from the net when the sealions grabs the fish and swims about 30 ft. away and starts thrashing (shredding) the fish, the guide grabs a seal bomb, lights it and lets the fuse burn down so that it will explode shortly after hitting the water, he tossed it to within a couple feet of the sealion and the sealion put his face under the water to check it out just as it goes off, mr. sealion totally stunned is now on the surface doing a big circle on his back when the guide gets the idea to cast a 16 oz. leadhead jig out thats on a bottom rod with 80lbs. tuffline on the reel, he casts over the sealion then reels the jig to within a couple feet then sets the hook, the sealion doesn't react and the guide is actually able to drag this sealion (still doing the backstroke in a big circle) close to his boat, he now grabs his gaff hook and clubs the sealion on the first 2 passes by the boat, seeing little effect he decides on the 3rd pass to stick the gaff right behind the flipper, mr. sealion suddenly comes out of his concussion and spins around and bites the gaff and dives under the boat, the guide lost site of the sealion for about 15 minutes till he see's it floating about a 100 ft. behing the boat, gaff hook in the lung finished him off. Another guide from another resort watched the whole thing, said it was a pretty impressive show, wish I could have seen it!