The Institute of Cetacean Research, the government group that operates Japan’s widely criticized research whaling, suffered a nearly crippling financial blow last year when its annual hunt in the Antarctic Ocean was disrupted by an environmental group, a Japanese newspaper reported Tuesday. It said the institute suffered a loss of $20.5 million, requiring additional financing from the government. The newspaper said the group, Sea Shepherd Conservation Society, limited the whaling fleet’s catch to 172 whales, or one-third of its take the year before. The institute relies on the sale of whale meat to finance a large part of its operations, experts say.