Habitat associations of grouper (Teleostei: Epinephelidae) assemblages across reefs in the Bidong Archipelago, Malaysia

AMINUDIN MUHAMMAD AFIQ-FIRDAUS (Institute of Oceanography and Environment, Universiti Malaysia Terengganu. 21030 Kuala Nerus, Terengganu, Malaysia)
CHE DIN MOHD SAFUAN (Institute of Oceanography and Environment, Universiti Malaysia Terengganu. 21030 Kuala Nerus, Terengganu, Malaysia)
MAIZAH M. ABDULLAH (Faculty of Science and Marine Environment, Universiti Malaysia Terengganu. 21030 Kuala Nerus, Terengganu, Malaysia)
EZMAHAMRUL AFREEN AWALLUDIN (Faculty of Fisheries and Food Sciences, Universiti Malaysia Terengganu. 21030 Kuala Nerus, Terengganu, Malaysia)
RAHMAN SYAHPUTRA SYAFRUDDIN (Institute of Oceanography and Environment, Universiti Malaysia Terengganu. 21030 Kuala Nerus, Terengganu, Malaysia)
MOHMAD FUAD NUR QAMARINA (Institute of Oceanography and Environment, Universiti Malaysia Terengganu. 21030 Kuala Nerus, Terengganu, Malaysia)
YUZWAN MOHAMAD (Faculty of Science and Marine Environment, Universiti Malaysia Terengganu. 21030 Kuala Nerus, Terengganu, Malaysia)
ZAINUDIN BACHOK (Institute of Oceanography and Environment, Universiti Malaysia Terengganu. 21030 Kuala Nerus, Terengganu, Malaysia)

Biodiversitas Journal of Biological Diversity
Vol. 27 No. 4 (2026)

Abstract. Afiq-Firdaus AM, Safuan CDM, Abdullah MM, Awalludin EA, Syafruddin RS, Qamarina MFN, Mohamad Y, Bachok Z. 2026. Habitat associations of grouper (Teleostei: Epinephelidae) assemblages across reefs in the Bidong Archipelago, Malaysia. Biodiversitas 27 (4): d270426. https://doi.org/10.13057/biodiv/d270426. Groupers (Teleostei: Epinephelidae) are important predatory fishes in coral reef ecosystems, yet their relationships with coral habitat remain insufficiently understood. This study aimed to evaluate grouper assemblages are structured by coral genus composition and benthic habitat, including live coral cover, across reefs in the Bidong Archipelago, Malaysia. Surveys were conducted at 18 stations between March and May 2022 using 100 m belt transects (5×100 m). Grouper assemblages were recorded using Underwater Visual Census (UVC) with video support, while benthic composition and coral genera were assessed using Coral Video Transects (CVT). Data were analyzed using canonical correspondence analysis (CCA), non-metric multidimensional scaling (NMDS), PERMANOVA, and Spearman correlation. A total of 388 individuals representing 11 species were recorded. Assemblages were dominated by Cephalopholis formosa (27%), Cephalopholis boenak (26%), and Cephalopholis cyanostigma (24%). NMDS indicated substantial overlap among sites, suggesting weak spatial structuring of assemblages. Coral genus composition explained 48.9% of constrained variation in CCA but was not statistically significant (p>0.05), consistent with PERMANOVA results (R²: 0.492, p: 0.811). Benthic cover explained 36.0% of variation in CCA and showed a marginal effect in PERMANOVA (R²: 0.434, p: 0.078), with only the “other invertebrates” category showing a significant relationship (p<0.05). Spearman correlation analyses revealed no significant relationships between grouper abundance and habitat variables. Grouper assemblages in the Bidong Archipelago showed weak and largely non-significant associations with coral genus composition and benthic habitat variables, indicating that factors other than measured habitat characteristics may play a greater role in structuring these communities.