sentences:  The company markets very few variants of the fish sandwiches, but it does offer localized versions that are specifically tailored to meet taste preferences or customs of the various regions and countries in which it does business.Usually during the Christian religious period known as Lent, Burger King releases limited-time (LTO) variants on the sandwich that have different ingredients from the standard sandwich recipe.While the sandwich itself never has never been at the center of controversy, the sourcing of fish from Icelandic suppliers lead to a call for a boycott of Burger King because of Iceland's participation in whaling – despite a 1982 international moratorium on the practice.