You can legally catch crayfish within Cleveland Metroparks as stated in the Ohio Fishing License guidelines. One of the best methods is placing a net downstream of a large rock. By turning over the rock the current will carry the crayfish into the net. The best locations are in the Rocky River and the Chagrin River. I would stay in the main river as there is a large number of non-native Rusty Crayfish (Orconectes rusticus) and are easy to capture. They can be very abundant in the spring – summer months. Here is a website that has some more information http://barbsandbacklashes.files.wordpress.com/2010/07/rusty-crayfish-fact-sheet.pdf
This is a great activity for the whole family!
Thanks for the question!