Other areas seem to support fairly healthy populations of some of the over NUMBER@1 different species of tuna -- for example , the central and western LOCATION@1 skipjack tuna , Katsuwonus pelamis -- but there is mounting evidence that overexploitation threatens tuna populations worldwide .

Other populations seem to support fairly healthy fisheries -LRB- for example , the central and western LOCATION@1 skipjack tuna -RRB- , but there is mounting evidence that overfishing threatens tuna fisheries world-wide .
