Icelandic whalers kill blue whale, activists say, first in 40 years (cnn.com)

I can think of a semi-decent way of addressing this. Start issuing a Letter of Marque to anyone that wants to patrol and challenge pirates annnnd just happen to throw in a line or two about whaler vessels.

I bet after a few international news stories about some whalers being shredded by 120mm guns the crews would start thinking up other ideas for income.