yes they did discover the blue catfish

Yes. The blue catfish is found in many states, including Michigan.

Unless it is a localized indigenous name, (common in the American South) they are known (properly) as "Blue Catfish", a specific species of catfish.

It eats fish

Blue catfish are the largest American catfish.Found in a variety of habitats,they can grow over 100 pounds!They eat mostly fish,but will take a variety of baits,anything with a smell.I saw a man catching them on chunks of soap!Blue cats are powerful fish,and fight great when hooked.They spawn in spring,and the young resemble tadpoles.