On the last Saturday in April, paddle that yak to the south half of the lake, turn west into that large shallow cove and work your way towards or into the boat channels until you find fish. I'd start searching with a bait that covers quite a bit of water. Two lures fit that bill perfectly in the spring. Arm yourself with a jerkbait, and a spinnerbait. My choices for these are:
Jerkbait - LC Pointer 78, Husky Jerk, or Rattlin' Rouge.
Spinnerbait - Thinking small in size, Strike King makes a small version, or perhaps an 1/8oz beetle spin.
If you find them back in the channels, make sure that you work slowly as those fish will be quite spooky in such a confined space. Pickup a few tubes or a K&E Worm that you can fan cast far ahead of you and keep a low profile. Target both sides and the middle before you move forward.
As you get closer to the spawn (think 60* water temps) take a cruise along any shoreline with a hard bottom between 2' to 8' in depth. Look closely around any new weed growth and especially the inside edge. You can always look in those coves, but I suspect that the marl bottom has a pretty good layer of silt built on it. The Google Earth picture doesn't show the normal blue/green reflection of exposed marl. If you've fished this lake during prior spawning seasons, you should know where their spawning beds are going to be. The bass won't be too far away from those areas, just a little deeper.