Justin - I may have answered your question on our site, but here it is for general information:
You must have a PFD readily accessible. Readily accessible means within easy reach and not stored in a hatch or out of reach. Preferably it should be worn - it is surprising how fast the yak can drift away if you were to take a spill. Another good point - the paddle will float, but tie it to the yak. Again, you can easily drop it and see it drift out of reach. Not good. The only exception is during a surf launch and landing where you you may want it un-attached...
You must have a noise signaling device, like a whistle or horn. A marine grade whistle is $4 at Academy. Works good, lasts a long time, and is cheap.
If you are going to be on the water after dark / before sunrise, you will need a 360 degree white light. A lot of us use an AA batt powered light on a short mast behind our seat. No running lights or registration required... unless you strap a trolling motor to it.
Keep in mind that you want to be seen - try to avoid the dark yak colors, wear bright clothing, maybe choose a paddle with yellow or orange blades. With all the boat and PWC traffic here, you want to be seen and the fish don't care. And bring your fishing license... These are the bare minimum requirements to be on the water.
There are other pieces of gear that can improve your safety, help you find, catch, and store fish, store your rods / gear, anchor the yak, etc... That's when the fun begins...
Feel free to come to our meetings or join up when we go fishing or post any questions - we would be happy to help...