I’m like 90% sure this information isn’t on the encounter table for the Great Marsh so I think this is okay to ask?
Buggers keep fleeing on me ;-;
Wooper's flee rate according to Bulbapedia without being affected by bait or mud is 47.1%.
Source
You have a 50.284% chance of catching a Wooper with a Safari Ball at full HP without being affected by mud or bait.