I keep trying to level up but it says I have no room for another bait. How can I fix this?

While fishing, click into the lure button on the bottom right, then click the blue backpack on the left. This will show a page of jars and other things. The jars are bait, used to catch better fish. Click on one to select it, then exit the backpack, and click on the bait outside of the backpack on the bottom right, then click anywhere within casting radius. This will throw out the bait, activating it’s ability.