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.

The Asian green mussel Perna viridis is expanding across coastal systems of the Americas, creating demand for curated molecular references to support biosecurity, aquaculture monitoring, and comparative invasion studies. Here, we report the first complete mitochondrial genomes of invasive P. viridis from Brazil and the southwestern Atlantic, generated from two specimens collected in Santa Catarina, currently the southernmost documented sector of the Brazilian range. Long-range PCR, Oxford Nanopore sequencing, read-supported assembly, manual annotation, comparative mitogenomics, nucleotide-diversity analysis, protein-level divergence, and phylogenomic inference were used to generate and evaluate complete mitochondrial references. The two circular assemblies were 16,015 bp and 16,011 bp and contained 38 annotated features, including 13 protein-coding genes, 23 tRNAs, and two rRNAs, all on the H strand, with an identical A+T content of 67.5%. Pairwise comparisons among the four complete P. viridis mitogenomes analyzed showed high overall similarity but retained 20–125 SNPs/mismatches and one to 12 indel events. Gene order was conserved within P. viridis but differed from P. canaliculus and P. perna, and phylogenomics placed the Brazilian assemblies within the P. viridis clade. These curated mitogenomes provide initial complete mitochondrial references for future marker testing and comparative studies of P. viridis in the southwestern Atlantic, but the two-specimen dataset should not be used to infer population origin, invasion routes, or connectivity.

The Asian green mussel Perna viridis is expanding across coastal systems of the Americas, creating demand for curated molecular references to support biosecurity, aquaculture monitoring, and comparative invasion studies. Here, we report the first complete mitochondrial genomes of invasive P. viridis from Brazil and the southwestern Atlantic, generated from two specimens collected in Santa Catarina, at the current southern Brazilian invasion front. Long-range PCR, Oxford Nanopore sequencing, read-supported assembly, manual annotation, comparative mitogenomics, nucleotide-diversity analysis, protein-level divergence, and phylogenomic inference were used to generate and evaluate complete mitochondrial references. The two circular assemblies were 16,015 bp and 16,011 bp and contained 38 annotated features, including 13 protein-coding genes, 23 tRNAs, and two rRNAs, all on the H strand, with an identical A+T content of 67.5%. Pairwise comparisons among complete P. viridis mitogenomes showed high overall similarity but retained 20-125 SNPs/mismatches and one to 12 indel events. Gene order was conserved within P. viridis but differed from P. canaliculus and P. perna, and phylogenomics placed the Brazilian assemblies within the P. viridis clade. These curated mitogenomes establish a genomic baseline for molecular surveillance and future invasion-focused studies of P. viridis in the southwestern Atlantic.