Decades of overfishing have deprived the food industry of billions of dollars in revenue and the world of fish that could have helped feed undernourished countries, according to a series of studies released on Tuesday.

The Canadian, U.S. and British researchers behind the studies also said that overfishing is often the result of government subsidies that would have been better spent conserving fish stocks.

Fisheries contribute $225 billion to $240 billion to the world economy annually, but if fishing practices were more sustainable, that amount would be up to $36 billion higher, according to the four papers published in the Journal of Bioeconomics.