If your rich enough to afford yourself a mindwipe freely. Mindwipe nearly all into oxygen. Grab a scuba set and a Lazarus chowder (for stamina) they are easy to kite up and down the invisible sea barrier and they will never catch you if your careful, start by eliminating angry mate booster for an easier time. If using primitive gear, a spare crossbow is not a bad idea.
If you want to tame one I recommend using a icthy because I tamed one by using it. If you are try to pump up its stamina and speed. But obviously if your not like your a sarco master like me🐊🐊 you can use that. Use a crossbow and tranq darts or toxiant arrows because it reloads faster and guns don’t work underwater. Trust me I tried it. It didn’t turn out well. After like 20 tranq arrows it will be unconscious then get somewhere near 10 raw prime meat and BOOM!! You have a plesiosaur /\ if this helped
There is a glitch at the redwood on the center, where plesiosaurs will spawn really near the coast and whole groups of 2 or 3 are glitched in the water, meaning you can knock out multiple plesiosaurs at the time.
My trusty sarcosuchus made knocking my plesi exceedingly simple, for three reasons. The sarco is fast, it ascends quickly, and you can shoot from its back. Once I separated my plesiosaur from her friend and killed it, the procedure was simple. When the plesi reaches a certain height it begins to flee. I dragged her up then filled her with tranqs until she aggro'd again. Repeat process until unconscious. Simple with sarco.
I have some tips for easy taming plesiosaur lvl 1-30. You need: Tamed Ichtiosaur, Oxygen balloon, Raw Prime Meat or Raw Meat, 60 narcotics or under, any crossbow, toxicant (or tranquilizer arrows, but this will be longer). That's all. You don't need traps or anything else. Just swim to plesiosaur's face on ichtiosaur, shoot toxicant (or tranquilizer) arrows, swim away from plesiosaur, reload, and repeat this again. After he go to sleep, just give him some meat, and feed narcotics sometimes. When you are on Ichtiosaur, anglers and mantas don't hurt you. This will be easy!
The trick is to argo one, have him chase you into an underwater cave where he will not be able to fit through the door but his long neck and head does. when you do this he will not de-agro, you can then get a clear shot from the cave with a bow and tranq arrows
Taming one is not too difficult. A high level won’t take too many tranq to knock out. When it’s knocked out, feeding it a soothing balm will allow u to tame it quickly, even with regular raw meat. Don’t forget to separate the plesiosaur u want from others in the area. Good luck!