Cooking some mussels.
A lot of them seem to have a elliptical crease/crack that follows the ridges on the shell around the top and bottom of the mussel. Does anyone know if this is a crack or is it a feature of the shell?
Some don't have it, some have it more pronounced, some have it more subtly.
I thought it might just be a feature, but it could also be a crack if their shells are weaker at particular points.
Finally, should I cook or discard them?