Massive server lag and crash in ocean for massive squid spawnkill

What I expected to happen was...:
Build a house in the ocean.

What actually happened was...:
In my server i was building with fire and netherrack in the ocean but after 5 min the server crash, then i login and i noticed that the ocean was full of squids spawning and despawning instantly, i wasnt able to chat or send commands, i tryed gamerule Domobspawning false and that stoped the squids from spawning. (Edit: first time i wrote it wrong)
Then the server crashed again due to the massive memory usage

Steps to Reproduce:
1. Join a new server
2. Go to the middle of the ocean
3. Build something with fire and netherrack
4. Wait 5 min