Under Catholicism, all aquatic beings being considered “fish”, whale was deemed suitable for eating during Lent and other “fasting periods”
An alternative explanation could be that the Church considered meat to be “hot” in terms of raising the libido and therefore making it unfit for holy days, whereas meat considered “cold” due to submersion in water, such as whale or beaver was therefore acceptable.
By the end of the Middle Ages in Europe consumption fell into decline due to overexploitation of the whale stocks in nearby oceans and never really recovered.
The experienced whalers of Norway, Finland, Spain and Holland found themselves drawn towards the New World to continue their commerce and though some of their product made its way back to European markets it had fallen out of favour, even as a cheap commodity for the ‘poorer’ classes. By the eighteenth century it became ‘unfashionable’ and has remained so ever since.
Today, due to such long and blatant overfishing, whale has become an endangered species and is now outlawed throughout most of the western world.
Except for a short period of time during the post-World War II upheaval in the United Kingdom. In its wisdom the Food Ministry brought in corned whale meat as an unrationed alternative to other unavailable meats. The meat, marketed under the name ‘wacon’ was described as ‘corned whale-meat with its fishy flavour removed’ and was ‘almost identical to corned beef, except being more brown than red’ and the Food Ministry fully endorsed it, emphasising its ‘high food value’
Whale tastes, apparently, much more like reindeer or moose, its hairy cousins on land, than its gilled neighbours in the sea. It can still sometimes be found where gamey meats are common such as Norway, Iceland, and Alaska.