The Republic of the Marshall Islands (RMI) is a major custodian of one of the ocean's major natural resources: tuna. The commercial tuna fisheries sector is the most important economic sector in the RMI and is thus a substantial contributor to this tiny island nation's GDP. Tuna catch and its associated revenues has fluctuated in line with climatic events such as the El Niño/La Niña Southern Oscillation (ENSO) and, in the last decade, national fisheries development policies have begun to capitalize on the positive effects that ENSO warm events have had on the tuna populations. However, global warming is expected to have a significant impact on ENSO, and not necessarily in positive ways. This paper will focus on the relationship between environment and economic development in the RMI fisheries sector. In particular, the linkages between global warming and its effects on the tuna fisheries sector must be better understood and uncertainties accounted for so that impacts are appropriately addressed and integrated into sustainable fisheries development policies. Conclusions reached are that new fisheries development strategies that emphasize environmental-based planning are required. The emerging ecosystem-based approach to fisheries management is a start, as are the various international initiatives in furthering our understanding of the linkages between climate and ocean systems currently underway.