Mussels are (or used to be) HG’s favorite food. For almost half the year. HG/BSK live on Prince Edward Island, the delightful Canadian island where the oysters are among the best in the world. Scallops, clams, tuna, cod, hake are also wondrous. (In fact, the tuna is so good that it is often snapped up by Japanese buyers before HG/BSK get a chance to sample). PEI has been most famous for its excellent mussels (they are identified as such at fish counters and restaurants throughout the United States). When on PEI, HG/BSK get their mussels freshly harvested from nearby St. Peters Bay. They should be very good. They are not. Nothing wrong with the taste but the mussels are very small so the great funky joy of mussel eating is lost. (The PEI mussels sold at Whole Foods are both tiny and tasteless). What happened to those big, plump, juicy mussels HG/BSK relished for many years? HG is yet to get a satisfactory answer. If you want to taste great mussels you have to go to Belgium or France. Sad.
I don’t have an answer for you, but I’ve noticed the same problem with P.E.I mussels here in Frederick, Maryland. The flavor is excellent, but they are so small that, in a classic recipe like paella, they just get lost. My guess is that the mussels have become so popular that even the small ones are selling. I had some much bigger mussels on the coast of Maine, but the flavor was not as good.