Last weekend, Adam Welz snapped these photos of an interesting turtle basking on a rock near one of the islands. It turns out after inquiries to a herpetologist that the species is a SPINY SOFT-BELLIED TURTLE, common in New York State. It looks to be somewhat larger than the nearby red-eared sliders, so it is most likely a female (which could grow much larger, up to 19 inches). Adult females are usually more than twice the size of males.
It's good to see a native NYS species in the lake.