Use the ichthy they said... it's immune to shocks they said... that's fine I'll quickly swim done with no scuba gear and lure one to the surface...zap... surface is so near yet so far... manta finish the job
While your tame still might die anyway if you have a high hp dino that gets zapped by these whistle followall and swim away. If you can i managed to rescue my 140 rex that way. She had 8k health and lost around half with a normal saddle. I came back with my re and killed them with rock throw. (It was super effective)
Well I went on my icthy with my friend who said that nothing attacked them except for the squid things and maybe the plesiosaur. But I was swimming down and ran into a group of cnidera but thy didn’t go after me. I’m not sure if it was a glitch because before they did go after me on my icthy. I hope this helped.