Shovels are needed to dig up bait parts on Crab Shore.
You can get shovels in several ways, including by exchanging resources.
Note that you can swap the resource being requested for a different one two times for free. After that, you must wait 8 hours for the next free swap, or spend gems. Your first swap with gems will cost 2 gems, your second one 4 gems, and each one after that 6 gems.
You can also get Shovels by completing Merchant orders, and as a reward from the Daily Bonus or from Event Islands.
Use your shovels to dig up sand tiles and find bait parts. When you have collected a full set of bait parts you can make bait, and go fishing.
Just like other rarities (such as hooks, feathers, acorns, and bait), shovels do not take up space in storage.
Collect as many as you want!
To learn more about fishing at Crab Shore, check out the Fishing section