Not too get too far off track here but there may have been a type of
shellfish in the Northeastern coast of North America that produced a similar
dye to the Mediterranean mussel.  It is mentioned in the mid 17th century on
the coast of Maine, by at least one Englishman ( Josselyn).  I do not know
if this has been verified by modern biologists but it might pose some
interesting questions for those interested in prehistoric textile arts in
North America.  ps Cochineal can still be purchased in both bulk and for
home use, and it is a bit tricky for first time users, best of luck.