Marine microorganisms such as fungi and yeasts can adapt to extreme marine environment conditions and play different roles especially in the nutrient cycling and as bioindicator of ocean change. This study was carried out to isolate and identify fungi and yeasts associated with Holothuria (Mertensiothuria) leucospilota from Pangkor Island, Perak, Malaysia in order to determine their species richness. Two specimens of H. leucospilota were collected from Giam Island and Teluk Nipah Beach of Pangkor Island. Nine samples of fungi and ten samples of yeasts were isolated from the internal and external parts of the H. leucospilota specimens such as cuticle, tentacle, coelomic fluid, cloaca, cuvierian tubules, and surrounding sediment and seawater. Polymerase Chain Reaction (PCR) and DNA sequencing of the Internal Transcribed Spacer (ITS) region were applied for species identification of the microorganisms. Sequence analyses of the ITS region resulted in the identification of five genera of fungi i.e. Cladosporium, Curvularia, Polyporaceae, Acremonium, and Penicillium; and four genera of yeasts i.e. Sterigmatomyces, Pichia, Debaryomyces, and Candida with some of them could be identified up to the species level. The findings have significantly contributed to the recent information on the checklist of fungi and yeasts isolated from the H. leucospilota specimens from Pangkor Island.

Species identification of sea cucumbers that have undergone body deformation due to extensive food processing, e.g., beche-de-mer, is difficult, especially with the copresence of cases of unlabelled or mislabelled sea cucumber-based products on the market. Therefore, a study was done to determine the species identities of processed sea cucumbers from selected Malaysian markets using concatenated gene sequences of non-protein-coding 12S and 16S mitochondrial rRNA genes. Phylogenetic analyses, based on the distance-based Neighbor Joining method and character-based methods, i.e., the Maximum Parsimony method, Maximum Likelihood method, and the Bayesian Analysis method, of 47 ingroup sequences, representing 37 processed sea cucumber specimens, 6 reference samples, and 4 additional specimens, suggested the presence of 3 main clusters, i.e., gamat family, consisting of genus Stichopus and genus Thelenota; and timun laut family, comprising family Holothuriidae. A number of 3 gamat species, i.e., Stichopus horrens, Stichopus vastus, and Thelenota anax, were recorded. Meanwhile, the specimens of Holothuria (Halodeima) atra, Holo-thuria (Halodeima) edulis, Holothuria (Metriatyla) lessoni, Holothuria (Merten-siothuria) leucospilota, and Holothuria (Metriatyla) scabra were the 5 timun laut species that are grouped under the family Holothuriidae. The outcomes of this study can be utilised by enforcement agencies to monitor and overcome the issues of species substitution and product mislabelling of processed sea cucumber products in Malaysian markets.