They will hit very aggressively right up to spawn and then again a couple weeks after. They don't all spawn at the same time so that doesn't mean some can't be caught. It may be a larger percentage of males during the spawn. https://www.youtube.com/watch?v=yiGX3fa-Wo4
Catfish are under the trees, live or dead. A friend of mine wins contests hopping from proven holes under trees and dead fall snag piles. Heavy line and gear with lots of power used getting them out quick. https://www.youtube.com/watch?v=Nb8dD8-hIcA