Mod biologics
 

Does any mod increase the diversity of biological contacts available in scenarios?
We've got shrimp and whales. My main focus is to increase the variety and type of false contacts available to SONAR operators.

r/
feld

I think there are also fish swarms, and IIRC Sub Command also simulated false contacts, which were just to be considered water turbulences and such.

I believe you could add any new item you want to the game by creating a 3D model (Even if a hugely simplified one, even an invisible one), making it a biological entity and giving it a sound. But others more experienced in working with the databases will probably know best.