Think twice before you order up a plate of tuna sushi or grilled marlin or tuna steaks, as the world’s fish stocks of these pelagic species, known as Scombrids, are threatened with extinction due to overfishing, pollution, and habitat degradation, according to an International Union for Conservation of Nature (IUCN) study published in the July 15 issue of the journal Science.
The study, led by University of Miami Rosenstiel School of Marine & Atmospheric Science associate professor David Die, analyzed 61 species of fish from the Scombridae family, which includes pelagic fish such as tunas, bonitos, mackerals and Spanish mackerals, and billfishes such as swordfish and marlin. The study classified seven as threatened with extinction and four as near threatened for the IUCN Red List of Threatened Species, a list that classifies extinction risk at the species level.
The IUCN assessment, according to Die, provides a different viewpoint of marine resource conservation efforts than that of fishery management organizations. The IUCN says that in spite of a “healthy status” of several pelagic fish stocks, some species are heavily overfished with no resolve to stop the overexploitation of the animals, which is driven largely by the high prices attained at market. Die has been studying migratory tuna and billfish for more than 12 years and contributed information on abundance trends and biology parameters on the Atlantic version of these species of large tuna and billfish to the most recent IUCN study.
According to the report, three tuna species; the Atlantic Bluefin (T. thynnus), the Yellowfin (T. albacares), and the Albacore (T. alalunga) are listed as near threatened; the Southern Bluefin (Thunnus maccoyii) is listed as critically endangered, and the Bigeye (T. obesus), listed as vulnerable and the Blue Marlin (Makaira nigricans) and White Marlin (Kajikia albida) are vulnerable while the Striped Marlin (Kajikia audax) is near threatened.
“The best thing would be for consumers to be made aware of these findings, and hopefully be able to use them to guide their consumer choices, said Beth Polidoro, Ph.D, Global Marine Species Assessment, Marine Biodiversity Unit, IUCN Species Programme. “We also hope that the information presented will help governments to improve national and regional regulations for fisheries, such as developing and enforcing area-wide closures and/or quotas, and prohibiting or reducing fishing in important spawning sites for certain species.”