Though signs warn that the air-driven de-icers make “any ice” in the marina unsafe, a few dozen fishermen were on the frozen water Saturday morning, some shielding themselves in canvas shanties.

The ice in the middle of the marina was 8 inches thick, according to one angler’s measurement, and — at least for some — the brown trout were biting.

Racine resident Cary May, fishing the frozen marina for the first time, said he was excited when he learned the marina’s management had installed the water aeration system.