Although tropical tuna stocks in the western Indian Ocean are currently in a healthy state, there are a number of drivers that could potentially lead to overfishing. In the case of skipjack, investment in larger vessels by fishing firms is likely to result in an increase in the use of FADs (Davies et al. FAD), and in turn fishing mortality of skipjack stocks. Signs of growth overfishing in the Atlantic Ocean in the late 1990s were attributed to the intensive use of FADs [20], and there is concern that unchecked expansion of FAD fishing in the eastern Pacific Ocean may ultimately lead to overexploitation of regional skipjack stocks [31]. Also, although skipjack are caught mainly in the purse seine fishery (38% of catch share in 2010), large quantities are also caught by vessels using gillnet (36%), pole-and-line (17%) and miscellaneous gears (9%; [27]), and growth in these fisheries would be expected to increase fishing pressure on skipjack stocks.