The Magnuson-Stevens Fishery Conservation and Management Act defines individual transferable quotas (ITQs) as permits to harvest specific quantities of fish of a particular species. Fisheries scientists decide the maximum annual harvest in a certain fishery, accounting for carrying capacity, re-generation rates and future values. This amount is called the total allowable catch (TAC). Under ITQs, participants in a fishery receive rights to a portion of the TAC without charge. Quotas can be fished, bought, sold, or leased. Twenty-eight U.S. fisheries have adopted ITQs as of 2008. Concerns about distributional consequences led to a moratorium on moving other fisheries into the programme that lasted from 1996 to 2004.