I know people fish below the dam at PK.
For a lake that hasnt had the spillway open, Will there be fish worth catching that are also released with the water(Bait fish, Cats?)

I fished damn near every good floodgate in Texas for a good 15 years..I admit it's been 15 yrs since then as I now fish from boat..that being said, all flood gates fish very differently...Flood gates always fish best for big cats when water is flowing...caught my biggest 65lbs and most (33 in one night) flatheads when the gates were wide open! Same with hybrids, striper, and sandies..no current no bite! Go down to the first deep hole down stream when the water stops flowing and the fish will stack up in those holes pretty good...good luck...pm me if you need rigging advice, each floodgate required different kinds of rigging from tight lining in big current for monster cats to slip bobber flowing water for stripers..if you don't have the right rig floodgate fishing you won't catch [censored]

Spillways and flood gates are 2 different things...I fished floodgates FYI

Over on the bank fishing forum they have a good video on the Lake Somerville topic. They are catching some good catfish, hybrids and other fish. Have to watch a little bit to get to the fishing.

You should search DAMFISHERMAN on here and send him a PM. That dude is the dam master. Although, I'm not sure he gets on here anymore. He runs a FB page called Catfishgods. He could answer any question you have about spillway fishing.