The IUCN (International Union for Conservation of Nature) has updated the seafood Red List and the results do not look great for tuna. According to the Red List five species of Tuna are of concern. This includes the endangered Bluefin Tuna but also classifies the Bigeye Tuna as vulnerable and Yellowfin Tuna and Albacore Tuna as near threatened. The results have come under some criticism for not further clarifying that some of these tuna species may actually have healthy stocks depending on the fishery and location. For example certain Albacore fisheries that have been properly managed and sustainably fished. However, the report is a good indicator of the general state of the fisheries and should not be overlooked. Now, more than ever it is important as a consumer to choose canned tuna from sustainable sources and healthy fish stocks.
Read a summary of the report at the IUCN website