Over the years she researched in some 40 archives - parish, municipal, notarial, judicial, etc. - in places such as Tolosa, Bilbao, Burgos, Valladolid, Madrid, Seville and Lisbon.
This detailed documentation allowed her to establish that the Basques had carried out, in different specific areas of Atlantic Canada, a prosperous cod fishery as well as a major whale fishery on an industrial scale during the 1500s.