Certain mobs not spawning (when they normally would)

Long story short, a mod is causing some aquatics to not spawn naturally on my server (alex's mobs: cachalot whale, frilled shark, orca, hammerhead shark. Vanilla mc: squid, dolphin). I'm not sure if its because we have 1.17 update backport mods or something else (of which if we were to remove them it'd probably corrupt the server at this point). The only mob of which I've stated I've seen was a squid so I know they do spawn but if at all; extremely rarely.

(attached 2 images of the complete modlist on my server)
Server version: 1.16.5 Forge 36.2.0

Suspected mods:
- Caves and Cliffs backport
- Deeper in the caves - warden mod
- the twilight forest
- the undergarden
- roadrunner
- sulfuric