Yonathan Zohar, Jorge Gomezjurado and Odi Zmora check on bluefin tuna larvae in tanks at the University of Maryland Baltimore County's Institute of Marine and Environmental Technology. Courtesy of Yonathan Zohar hide caption

itoggle caption Courtesy of Yonathan Zohar

A tuna fishing boat drags a cage of nets on the Mediterranean sea in 2010. (The Mediterranean is not considered to be part of the "high seas.") Andreas Solaro/AFP/Getty Images hide caption

itoggle caption Andreas Solaro/AFP/Getty Images

A Tokyo sushi restaurant displays blocks of fat meat tuna cut out from a 269kg bluefin tuna. Yoshikazu Tsuno/AFP/Getty Images hide caption

itoggle caption Yoshikazu Tsuno/AFP/Getty Images