of all northern right whales killed by human activities are from ship collisions, calling for restrictions on the movement of shipping in certain areas. Noise pollution threatens the existence of cetaceans. Large ships and boats make a tremendous amount of noise that falls into the same frequency range of many whales. By-catch also kills more animals than hunting. Some scientists believe pollution to be a factor. Moreover, since the IWC moratorium, there have been several instances of illegal whale hunting by IWC nations. In 1994, the IWC reported evidence from genetic testing of whale meat and blubber for sale on the open market in Japan in 1993. In addition to the legally permitted minke whale, the analyses showed that 10–25% of tissues sampled came from non minke, baleen whales, neither of which were then allowed under IWC rules. Further research in 1995 and 1996 showed a significant drop of non-minke baleen whales sampled to 2.5%. In a separate paper, Baker stated that "many of these animals certainly represent a bycatch (incidental entrapment in fishing gear)" and stated that DNA monitoring of whale meat is required to adequately track whale products. It was revealed in 1994 that the Soviet Union had been systematically undercounting its catch. For example, from 1948 to 1973, the Soviet Union caught 48,477 humpback whales rather than the 2,710 it officially reported to the IWC. On the basis of this new information, the IWC stated that it would have to rewrite its catch figures for the last forty years. According to Ray Gambell, then-Secretary of the IWC, the organization had raised its suspicions with the former Soviet Union, but it did not take further action because it could not interfere with national sovereignty. Health risks Whales are long-lived predators, so their tissues build up concentrations of methyl mercury from their prey. Mercury concentrations reach levels that are hazardous to humans who consume too much too often, since mercury also bioaccumulates in humans. High levels have been found in the Caribbean, where people are advised not to exceed one serving every three weeks, in the Faroe Islands, and in Japan. Effects of whaling on global carbon cycles Scientists have analyzed the ability of the oceans to sequester atmospheric carbon before whaling and in modern times, hundreds of years after the most active whaling periods. Focusing on the amount of carbon stored in baleen whales, scientists determined that large