There is no single "noisiest" sea creature, as noise can be measured by loudness, frequency, or purpose. Strong contenders include:
Blue Whales: Calls can reach 188 decibels for long-distance communication.
Sperm Whales: Clicks for echolocation can reach 230 decibels in focused beams.
Shrimp: Snapping claws produce pops up to 218 decibels for hunting and communication.
Fish: Many species communicate with grunts, clicks, and whistles.
The "noisiest" creature depends on how noise is defined.