[Nullinker]

But we should also not underestimate the ability of the enemy to train dolphins.

It would be hard to send an strike team of just dolphins but I imagine a strike team of both humans and dolphins trained to fend of the defending dolphins and protect the divers would stand a chance.

[BasilPH]

AFAIK dolphins are never used together with friendly divers against other divers as the dolphins can't discern between friends or foes.

[smilespray]

Just make sure the enemy team wears red diving suits and the friendlies wear blue ones. Foolproof!

[hugh-avherald]

How does the enemy get the trained dolphins there? And once discovered, an attack, dolphins or not, isn't going to have much success.