Today number of whale had decreased continuously so in the early '80s, there was a ban on commercial whaling but Whales are still low in numbers.
The benefits of whale are
They help maintain the stability and health of the oceans, and even provide services to human society and when whales dive to the depths to feed and come up to the surface to breathe they release these enormous fecal plumes that stimulate the growth of plankton and plankton is base of all marine food chains if in the oceans more of whale poo it will benefic to ecosystem
And when whale, Migrations to other ocean, whale can released feces in other ocean in the world and it can Keep the balance of the ecosystem those ocean. And then when whale are dead, Whale carcasses can help to delay global warming and it also wash up on beaches and provide a meal to a number of predatory species on land. So whale and whale poo are important everyone should to protect it and if we kill many of whale there will be impacts on the marine ecosystem.