Without the water wheel to increase the oxygen level in the water, the rate at which he blew bubbles would be a lot slower.
The most important thing was that there was a limited supply of water here. With the limited water region, he couldn't extract oxygen as readily as when he was in the sea.
Thankfully, he had already blown over 20 bubbles, and it wasn't an issue to blow another 20 more. It was just that his speed would be a lot slower.
Late at night, the entire village was filled with bellows and agonizing cries from beastmen that one could hear even from afar. A tiger stopped in his footsteps, hesitated for a moment, then ran over to the source of the sounds.
Winston sent the females to the waterhole in succession, prioritizing those who didn't have many mates. As more and more male beastmen were freed from the shackles of having to protect their females, they started to gain ground in the battle.