Original: Other areas seem to support fairly healthy populations of some of the over 48 different species of tuna —for example, the central and western Pacific skipjack tuna, Katsuwonus pelamis—but there is mounting evidence that overexploitation threatens tuna populations worldwide.
Simplified: Other populations seem to support fairly healthy fisheries (for example, the central and western Pacific skipjack tuna), but there is mounting evidence that overfishing threatens tuna fisheries world-wide.