Global commercial tuna catch is dominated by a handful of species, and skipjack sits at the top. In recent decades it has represented roughly half of the total tuna tonnage landed, with yellowfin second and bluefin a small fraction of the whole despite its cultural prominence.
The reason is life history. Skipjack mature at about a year old, spawn opportunistically through the year in warm water, and rarely live long. A population of short-lived, fast-reproducing fish replaces itself quickly, so it can support a heavy fishery that would flatten a slow-growing, late-maturing species such as bluefin. Most skipjack are caught by purse seine, much of it in the western and central Pacific.
Resilience is not immunity, and the pressure has shifted rather than vanished. Fish aggregating devices concentrate skipjack for capture but also gather juvenile bigeye and yellowfin as bycatch, so a skipjack-directed fishery can bear on the stocks of slower species. How much FAD fishing depresses those stocks is one of the main live arguments in tuna management.