Where i tamed it there was actually much bigger swarm, you might try to separate the one you want and get it closer to the shore but it will start running eventually, i tamed lvl 108 with scuba gear and used mindwipe to reset my skills, get at least 200-300 stam and rest put in oxygen so you are fast, i had 700 oxygen

Things you will need:

Scuba gear
Spyglass
10 Shadow stakes(cause it might easily take overnight)
Around 200-230 tranq arrows with mastercraft crossbow with damage 215%(see more below)
Around 22 kibble for 108 lvl 1.5x taming rate
Narcotics(don't know how much exactly but its not dropping fast once unconscious), take few hundreds

The amount of arrows is because i had stam 200 and had to swim to shore several times to get staminia and eat shadow stakes to see in night, in the meantime the topor might dropped + it will take a little to find the one in the swarm again and dodge the others, so just saying, take loads of arrows to be safe

Ty for your answer, but there is a problem.

Im running a selfmade Primitive Server without electrics and Fabricator and stuff like this, so no Scuba Gear ^^

Are they spawning in swarms or they are "finding them together"? Maybe i try to reduce spawnrate.

We also have a big swarm in front of our base. My Admin told me, that when he reduces spawnrate, it would also affect other dinos.

I kinda like it to be that dangerous there, and it is possible to tame one. It is as osmit said, lure one away.

I lured away a pack, cause they help each other, and then when there were only 4 or so left, i killed the ones I didn´t want and the last one was suddenly all of his own :P