A Crusade Throughout the World’s Oceans: Genetic Evidence of the Southern Bluefin Tuna Thunnus maccoyii and the Pacific Bluefin Tuna Thunnus orientalis in Brazilian Waters

• Published in: Biology (Basel, Switzerland) Vol. 14; no. 4; p. 340
• Main Authors: Schroeder, Rafael, Sant’Ana, Rodrigo, Lima, André O. S., Dallabona, Juliana A., Delabary, Gabriela S., Gavazzoni, Lucas, Oliveira, Luciana de, Laaf, Yan de O., Travassos, Paulo
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 26.03.2025; MDPI
• Subjects: Analysis; Bar codes; Bats; Bluefin tuna; Climate change; Climatic changes; Commercial species; DNA polymerase; Endemic species; Fishes; Fishing; Gene amplification; Genetic testing; Identification; Longlining (Fisheries); Marine ecosystems; Mitochondrial DNA; North Pacific; Oceans; Phylogenetics; Software; species range extension; Thunnus maccoyii; Thunnus orientalis; Thunnus thynnus; Tuna; zoogeography; Brazil; Mexico; United States; Atlantic Ocean; Pacific Ocean; United States > US; Switzerland; bluefin tuna; Southwest Atlantic; species range extension; zoogeography; Thunnus orientalis; Thunnus maccoyii; Indic Ocean; North Pacific
• ISSN: 2079-7737; 2079-7737
• DOI: 10.3390/biology14040340

The large pelagic species play an important role in transferring energy in vast distant marine ecoregions. Results obtained report on extraordinary findings of important commercial species in southeast–south Brazilian waters, including the Southern bluefin tuna Thunnus maccoyii and the Pacific bluefin tuna Thunnus orientalis, an endemic species from the Pacific Ocean. These specimens were identified within the genomic description of 10 individuals randomly selected from the catch to evaluate the catch composition of pelagic longline fisheries off Brazilian waters. Most of the records were from T. maccoyii (6), followed by the Bigeye tuna T. obesus (2), Yellowfin tuna T. albacares (1), and T. orientalis (1). Yellowfin and Bigeye tuna are expected to be captured in the vicinity of the longline fishing areas. However, the unlikely presence of the cold-water T. maccoyii and the warm-water T. orientalis suggests a long migration from common species ranges that could be influenced by climate change. These results imply a readjustment of spatial management structures for these species.