Harbor Seal
Harbor seals are not uncommon in the winter, but kayaking is, so don't expect to encounter them when you are out for a paddle.
-- Wikipedia
Common Dolphin
On the other hand, the Common Dolphin prefers warmer weather, and can be seen all through kayaking season. They go south for the winter.
-- Wikipedia
These are some mammals you are likely to see in and around the water.
More: Mammals ...
Your new boat probably came with a paddle. I've never seen a boat come with a good paddle. It is just a starter, to get you going. Get a good paddle that is the right size for you. It will make a world of difference. Keep the old one for a spare. Rule of thumb: your paddle should be about your height. If you install a thick seat cushion, you might want to go a little longer even.
I regard my paddle as an emergency signalling device as well, which is why I like the yellow color pictured, especially if your boat is some camouflage shade of green.
More: Paddles ...