Revenue from tuna caught within the Economic Exclusive Zones of Pacific Island Countries is expected to decline by 2050.
This is the view of Conservation International's Johann Bell.
The PACNEWS agency reported climate change will affect revenue generated from the industry.
Mr Bell said their recent modelling has looked at how the biomass of tuna might change around the island countries and how it might change on the high seas.
He said it showed that by 2050 there is likely to be a 15 percent movement of the amount of tuna in the EEZ onto the high seas.
Bell said climate change will continue to increase the surface temperature of the ocean and this will cause skipjack and yellowfin tuna species to shift significantly to the East.
He said a promising way to cushion Pacific island economies against a loss of license revenue would be to explore how best to add value to tuna.