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A genetic assessment was done on the greenblotch parrotfish (Scarus quoyi Valenciennes, 1840) in three bays within southern Mindanao, Philippines. Mitochondrial 16S rRNA recovered 12 haplotypes, one of which was dominant in all sites. Despite the reported phenotypic variation from previous assessments, there was neither evidence of genetic structure (global Φst = 0.012, p = 0.13) nor isolation by distance (r = 0.05, p = 0.50). Genetic diversity was also low (Hglobal = 0.472; πglobal = 0.13%), with ~ 77% of haplotype diversity accounted for with just 69 samples. While connectivity suggests continuous larval exchange within southern Mindanao owing to the species’ high dispersal potential, low genetic diversity implies reduced effective population size, probably due to recent bottlenecks (e.g. overfishing, habitat destruction). Although this study provides baseline genetic information on the local population, inferences are considerably limited by the genetic marker used and the spatial scale under investigation. A thorough understanding of the population will be possible if the entire habitat range of the species is assessed using markers with high resolving power, such as the hypervariable mitochondrial control region, microsatellites, or genome-wide single nucleotide polymorphisms (SNPs).

DNA barcoding was done to identify the dominant species of sardines that comprised the landed catch of the sardine fishery in the Northern Mindanao Region (NMR), and juveniles or "lupoy" in the Northern Zamboanga Peninsula (NZP). Cytochrome oxidase I (COI) minibarcodes were sequenced for all samples, while 16S ribosomal subunit sequences were obtained from a subset of samples. In reference to a previously reported land catch survey, sequence data confirmed the identity of the most dominant sardines in NMR and lupoy from NZP as Sardinella lemuru. Meanwhile, those reported as S. gibbosa were identified as Herklotsichthys quadrimaculatus, while those reported as S. pacifica were identified as the recently described S. goni. Results highlight: 1) the limitation in identifying sardines during land catch surveys without further taxonomic verification, and 2) the utility of DNA barcoding as a tool for species identification. Moreover, genetic data revealed that S. goni occurs in the fisheries of NMR, thereby expanding its known habitat range. Since this study was limited only in using DNA barcodes for identification, a detailed morphological examination of the dominant sardines is recommended.