Status of the World Fisheries for Tuna. March 2023

The 23 stocks of the 7 major commercial oceanic tuna species are assessed and managed by five Tuna Regional Fishery Management Organizations (RFMOs). The purpose of this document is to summarize the status of the stocks according to the most recent scientific assessments, as well as the current management measures adopted by the RFMOs. The report is reviewed by the ISSF Scientific Advisory Committee, which provides advice on its content. The report does not advocate any particular seafood purchase decisions.

...

Are the methods used to catch the tuna also catching significant numbers of non-targeted species? The report also measures the environmental impact of fishing in terms of “bycatch” rates. Bycatch is any species caught by the boat that is not targeted by the skipper. All fishing methods result in some bycatch of non-target species. The report identifies the relative bycatch rates by fishing gear and reports on mitigation measures adopted by the RFMOs for various species groups.