Like all whales, the blue whale is a mammal and not a fish. It is warm-blooded, has lungs rather than gills, and nourishes its young with milk. A blue whale's milk tastes like a mixture of fish, liver, milk of magnesia, and castor oil. Unlike cow milk which generally contains 4-6% fat, whale milk and other marine mammals have milk fat percentages in the 40-65% range. Fatty milks are like slurping very soft butter and make a perfect base for ice cream. Since the milk already has a high fat content the only real step in the production of whale's milk ice cream is to slowly cool it and whip it into a creamy consistency. The completed ice cream maintains the wonderful tastes that you would expect to come from a marine animal. Don't even think about eating whale milk ice cream if you are watching your weight because this ice cream contains 900 calories per half cup serving.
The question that always gets asked is how the milk is collected from the whale.THe method is pretty much what you would expect, they put on scuba gear and swim under the whale and grab on to one of its teats. The whale will pull you along as long as you hold on and then grab another teat and squeeze like you would with a cow (only much bigger). The milk is very thick due to the high fat content (the consistency is similar to mucus) so they capture it in a fine net like you would use too skim a swimming pool. Once theyhave a full net of milk they let go of the whale's teat and swim back to the boat where they transfer the milk into a bucket and then refrigerate it.
The rest of the process is pretty much like making normal ice cream.they have also experimented with whale's milk yogurt, cheese, butter, and cottage cheese but my favorite is the ice cream because it's simply excellent. the ice cream because it's simply excellent.
This is the closest answer I can find