It's not necessary but it's lame to immediately condemn it. To some people apparently the life of a whale is worth more than that of a chicken or a cow, which in my eyes smells like good old hypocrisy. However, countries that rely on whaling should also make sure that the population of whales is maintained. (In the same way, cows and chickens are used for their meat all the time but at least their species isn't endangered.) If Japan wants to continue its whaling practices they should also be made responsible for the safety of the whale as a species.

No, whaling is not essential to humanity's survival, but it is important to note that whaling provides jobs and a way of life for many people in different parts of the world, namely Japan. It is not possible to eliminate whaling without providing a viable alternative for those whose livelihoods depend upon it. Since it is not likely that whalers would embrace a different form of employment, the most realistic solution would be to closely monitor whaling practices and to try to slowly introduce whalers to other jobs, probably ones involved with or in the fishing industry (although, with today's over-fished waters, that's quickly becoming contentious, as well).

It is possible to become vegetarian. If whales were the only animal. It is possible to make products from other materials. The survival of humanity does not rely on defending ourselves from attacking whales. Whales do not attack as far as I know. My conclusion is I do not think whaling is a necessity for the survival of the humanity. But then it is still possible some day to manage effectively whaling practices.

I don't think so. Whales don't provide any essential goods, we couldn't produce synthetically. Perhaps it is easier to receive the goods and some luxury goods rely on whaling, but this doesn't make it a necessity.

It depends on where you live. For example, in Alaska, there are many communities who depend on whaling. It's part of their lifestyle. However, for any place that depends on whaling as a way to get by, it is necessary to maintain the whale population. Obviously. Otherwise, it's not a lifestyle for long.