Establishment of sea cucumber Stichopus spp. broodstock population by species determination through morphological and DNA barcoding analysis

Sea cucumbers belong to the phylum Echinodermata, and one of their notable genera is Stichopus. Commonly known as gamat in Southeast Asia, these species are widely traded worldwide as raw materials for pharmaceutical applications. The increasing exploitation has caused this genus to become endangered. Therefore, it is necessary to initiate cultivation by providing seeds from the hatchery. Stichopus has many species and is very similar among species. Consequently, it is necessary to obtain broodstock with proper determination. To ensure correct identification, both morphological and molecular approaches were used. Morphological identification was performed against six individuals, which were visually estimated to represent the species, using external and ossicle characteristics observation. Meanwhile, molecular identification with DNA Barcoding markers starts with DNA extraction and purification, amplification, PCR product electrophoresis, and sequencing-similarity analysis using the unweighted pair-group method using arithmetic averages (UPGMA) with the MEGA program version 11. Morphologically, six species were identified, including Stichopus herrmanni , S. horrens , S. ocellatus , S. quadrifasciatus , S. rubermaculosus, and S. vastus . However, according to BLAST results generated using sequences in GenBank, the specimens matched four different species. Notably, two samples that had been morphologically identified as S. quadrifasciatus and S. rubermaculosus were instead identified as S. horrens , showing a similarity value of 99–100%.