We were cruising the Santa Rosa Costco a couple of weeks ago and could not find the six-packs of anchovies (Crown Prince brand). We checked with the folks up front and they don't show anchovies as a stock item at all.
Rohnert Park Costco doesn't have them - and hasn't for quite a few years. We assume demand was too low and the product didn't move enough to justify it's shelf space.
We've stopped by the customer feedback area and put in a form asking that they bring back the anchovies. This is between the food court and the tire shop. If a number of us ask, and then buy, we may get the anchovies back!