Direct Enhancement of Snapper Conservation and the Economy through Novel Devices Act of 2019 or the DESCEND Act of 2019 This bill addresses the use of descending devices to release reef fish in the Gulf of Mexico. (A descending device is an instrument that will release fish at a depth sufficient for the fish to be able to recover from the effects of barotrauma.) Specifically, the bill requires commercial and recreational fishermen to possess a venting tool or descending device that is rigged and ready for use when fishing for reef fish in the Gulf of Mexico Exclusive Economic Zone, the Department of Commerce to contract with the National Academy of Sciences to conduct a study and produce a report on discard mortality in the Gulf reef fish fisheries, and Commerce and the Gulf of Mexico Fishery Management Council to develop guidance for reporting discards and associated mortality and develop a plan to assess the effectiveness and usage of barotrauma-reducing devices.