I have been wondering the same thing for years and have not come up with any concrete answer. I do believe any kind of bait in shallow (grunion, smelt, anchovies, etc.) draws the fish in which is always a good thing. If the fish aren't there you're never going to catch them - whether they're hungry or not.

My catches seem to be slightly better around a grunion run but not enough to provide any solid evidence that the grunion run was the reason. It could just be because I fished more around that time.

Anyone else?