In Japan the Bluefin tuna is particularly prized (a single large fish can fetch more than $ 100.000).
The large demand in this country led to aggressive fishing practices and the populations today are a tenth of what they were in the 1950s.
The decline is faster everyday because of open-ocean pens where wild juvenile tuna are put: these animals are removed from the wild before they have spawned and this is deleterious for the survival of the species.
http://www.worldwildlife.org/species/bluefin-tuna
