Heading into last weekend’s long-awaited chinook salmon fishing opener, Willy Vogler was ready for chaos. After a two-year shutdown, anglers across the California coast were eager for the return of recreational fishing—though only for two tightly regulated days. 

“Everybody was worried the launch ramps would be a total madhouse,” said Mr. Vogler, who runs the campground at Lawson’s Landing in Dillon Beach and writes a popular fishing blog. “And it was busy, no doubt,…