Genetic and taxonomic data corroborates the first report of lemon sharks, Negaprion brevirostris, in estuarine waters of Coiba National Park, Panama

For almost two years community structure, characterization and identification of the main fish species from the largest estuaries of Coiba have been the focus of our research interest. Among selachii elasmobranchs (sharks), three common species ( Carcharhinus limbatus , Carcharhinus leucas and Sphyrna lewinii ) have been collected during our fish collection campaigns in San Juan, Rio Negro and Boca Grande estuaries. These three species plus the white tip reef shark, Triaenodon obesus , have been previously listed as frequent along the islands of Coiba archipelago base on visual census and environmental DNA list provided by UNESCO in collaboration with COIBA AIP Scientific Station. From February to October of 2025, seven young of the year (YOY) individuals of the lemon shark ( Negaprion brevirostris ), a species non-reported in this area before, were collected in Boca Grande estuary (two individuals during our dry season sampling campaign (February) and five individuals during the wet season (August-Cctober). Taxonomic and genetic data analysis support that collected individuals corresponded to lemon sharks, N. brevirostris . To corroborate taxonomic identification, genetic identification of two individuals was conducted using PCR amplification and product sequencing of two mitochondrial gene segments (COI and Control Region). Sequences from both genes showed a 99.17% and 99.83% similarity with GenBank referenced sequences for N. brevirostris . One unique haplotype (accession number: PX453691 and PX453712) was obtained from Boca Grande N. brevirostris samples. This is the first confirmed report of the presence of this species in waters of Coiba National Park. Therefore, these are the first reported DNA sequences deposited on GeneBank of this species for Panama Pacific waters. This information will allow scientists to compare these sequences with others deposited in GenBank as references for Eastern Tropical Pacific and unravel the existence of philopatry as well as local and regional connectivity patterns. These results will be key to establishing new management and surveillance strategies in Coiba National Park such as declaring Boca Grande estuary as nursery area and potentially a shark sanctuary.