TAKSONOMI INTEGRATIF GOBIIFORMES MELALUI DNA BARCODING DAN ENVIRONMENTAL DNA DI DANAU BAGIAN UTARA SULAWESI = INTEGRATIVE TAXONOMY OF GOBIIFORMES THROUGH DNA BARCODING AND ENVIRONMENTAL DNA IN THE LAKES OF NORTHERN SULAWESI

Background. Gobiiformes are found throughout the Indo-Pacific region and contribute significantly to ichthyofaunal diversity in the Wallacea region, including Sulawesi. Despite advances in the identification of native lacustrine species, fish diversity data remain limited. Most studies rely on classical taxonomy (visual identification using morphological traits), with few using molecular biology approaches such as DNA barcoding and environmental DNA (eDNA). Objectives. 1). Review historical data on Lake Limboto Gobiiformes and ichthyofaunal community. 2). Collate recent Gobiiformes records from three northern Sulawesi lakes. 3). Examine morphomeristic and phylogenetic traits of Giuris sp. from three northern Sulawesi lakes. 4). Explore faunal biodiversity using environmental DNA metabarcoding in a northern Sulawesi lake. Methods. This study employed explorative methods with an integrative taxonomy approach at three sites: Lake Limboto, Lake Tondano, and Lake Bulano Sau. Fish specimens were collected using accidental sampling by local fishermen for DNA barcoding in August 2023, and water samples for eDNA were collected in February 2024 using the Sylphium protocol. Morphomeristic traits were measured for each specimen (digital scales, accuracy 0.1 g) and digital callipers (accuracy 0.1 mm). DNA barcoding used pectoral fin samples from the right side of each specimen (mitochondrial cytochrome oxidase I or COI gene fragment, primers Fish1/Fish2, Sanger sequencing). eDNA metabarcoding used MiFish primers (target 12S rRNA), Nanopore sequencing, and the POD5 bioinformatic pipeline. Results. Gobiiformes found in the northern Sulawesi lakes were native, but introduced species dominated the ichthyofauna. eDNA detected 20 taxonomic units representing 11 genera, highlighting the urgency of DNA barcoding for native Sulawesi fish. The dominance of introduced species, including several invasive alien species, underscores the need to optimize fish management practices to maximize benefits while minimizing environmental impacts, particularly on native fish. Conclusion. 1). Evaluation of historical data and the ichthyofauna community in Lake Limboto showed that the 10 fished species included two native Gobiiformes, while most were introduced fishes. 2). Four Gobiiformes species were identified in the three Northern Sulawesi lakes. A total of 14 DNA barcodes were obtained from 15 Gobiiformes specimens, including two species from the genus Giuris (G. laglaizei;G. aporocephalus), Oxyeleotris marmorata from Eleotridae, and Glossogobius aureus from Gobiidae. 3) Morphometric and phylogenetic traits of Giuris sp. identified the fish locally named payangka in Lake Limboto and Tondano as G. aporocephalus, while the payangka in Lake Bolano Sau comprised two species: G. aporocephalus and G. laglaizei. 4) Fauna biodiversity exploration in Lake Limboto revealed between-station differences in community structure, dominance of introduced fish, including invasive introduced species, and deteced additional Gobiiformes including possible additional Glossogobius species.