stop hunting them.
The biggest animal in the oceans is the whale; the largest of the whales is the Blue Whale at 100-120 tons. The Blue Whale is also on the endangered species list. You will find some Blue Whale facts on the link below.
This whale is on the endangered species list as it has not recovered well after being hunted to near extinction for their oil (in the tissues under the skin). Whale oil was used for lamps.
The gray whale is not an endangered species. Listed as "Least Concern" by the IUCN.
Most whales are on the endangered species list because they are being over hunted for their blubber, whale oil, and whale meat.
The grey whale was put on the endangered species list because of people over hunting them and habitat destruction
never
The killer whale is not an endangered species, listed as low concern by the IUCN.
None of the tangs commonly called Blue Tang - Powder Blue, Atlantic Blue, and Regal/Hippo/Blue(Paracanthurus hepatus - are on the endangered species list. So the answer is never.
they went endangered in the 1990's
No but they are on the endangered species list in California.
Since 1966, humpback whales have been labeled and protected as endangered. There are certain associations, groups, and fisherman, who are trying to get the government to release the humpback whales from the endangered list. Today, the humpback whale is listed as "Least Concern" by the IUCN. Not an endangered species.
The Blue Coua are not listed as "endangered", even though they are listed on an endangered species list. According to the International Union of Conservation for Nature, or the IUCN Red List, the Blue Coua is listed with a status of "least concern" currently. For more details, please see the sites listed below.