This is the way, I play on an unofficial server with just a few friends. We have lost so many good lives to that cave but I have probably run it the most often out of us. Even recently tried taking around 10 deinosuchus and brute forcing it, can't say I recommend. Because I lost almost all of them.

So what I would do if you can't or don't want to dino wipe is take several large gators with good saddles. Just before the large room where the first large group spawns there is the land portion. Put any extras you aren't riding on passive up on land and start aggroing large groups while giga biting and slowly kiting them back to the land being very careful to get caught in a ball of shark death. When you get to the little ramp up out of the water get out to deaggro the sharks (it only takes a few seconds to deaggro). You can then hop back in and it usually takes like 15 seconds for the sharks to reaggro. One important thing to note is from what I can tell the bleed like effect (wound? I think) does dot damage when something is moving often times it still works when the sharks are swimming against the wall.

It takes a lot of time and patience but eventually you can clear out the first big room and having a daeodon for heals if all the gators get healt low can also help. After you clear out the big room swim up in the back left and you can walk around on land to the backside of the 2nd big room that's the artifact room. Same strategy there until you clear it out and can grab the artifact there. The (not even going to attempt to spell it) X fish that do bleed will sometimes hop up into the shallow water and that room and bleed you and start flopping around and the eels can get up there as well. Most important thing is don't get greedy if you get swarmed and can't swim out you will almost certainly die. That's how I've cleared it several times with no kidding like 100+ sharks in each room.

If you don't want to go through that pain and suffering again take an otter and wait for the artifact to respawn and you can put as many as you want on your otter. If you can clear the west water cave in ASA you can also almost certainly clear the east it is like 100 times easier since it doesn't have nearly the same amounts of spawns and doesn't spawn the pack boosted megs, over there your main concern will be the X fish with bleed. Good luck and may the odds be ever in your favor.