abstain due to the mercury risks?
http://en.wikipedia.org/wiki/Tuna#Mercury_levels
http://www.cbc.ca/news/canada/manitoba/story/2007/02/19/tuna-testing.html
http://www.canadianliving.com/health/nutrition/ask_an_expert_mercury_levels_in_tuna.php
http://www.cbc.ca/news/technology/story/2010/04/20/tech-sushi-tuna-mercury.html
http://en.wikipedia.org/wiki/Tuna#Mercury_levels
http://www.cbc.ca/news/canada/manitoba/story/2007/02/19/tuna-testing.html
http://www.canadianliving.com/health/nutrition/ask_an_expert_mercury_levels_in_tuna.php
http://www.cbc.ca/news/technology/story/2010/04/20/tech-sushi-tuna-mercury.html