Aquatic Mobs NOT spawning

Aquatic Mobs (salmon, cod, pufferfish, etc..)are not spawning in 1.21.4.

Only in this world, no mob is spawning.

I tried to back-up, and launched 1.21.3 but nothing happened.

I tried world optimization.

I tried these codes, but nothing happened :

/gamerule doMobSpawning true

/gamerule spawnRadius 10

/summon cod ~ ~ ~ {NoAI:1}