I won't get as angry as blame bush (just look at her profile picture!) but other reason that compound their problem is that they require huge amounts of food, have a long life span (hence take a long time to reach maturity) and migrate. Migratory animals tend to be kinda hooped, because if the place that they're migrating to isn't within their niche, they've just spent huge amounts of energy for nothing. Yes, man made them endangered, the whaling industry kind of acted like a transitional phase from coal/wood to hydrocarbon based energy systems.
MAN is the cause. We would have millions of sperm whales if it werent for MAN. Did you know that the sperm whale mates for life and their calves can respond to human emotions. They have saved shipwreck victims from drowning and this is how we repay them. Iceland and Japan sailors and their govts are MURDERERS and they need to be jailed!!!!!