MEPS 677:81-94 (2021)  -  DOI: https://doi.org/10.3354/meps13863

ABSTRACT: On coral reefs, many small coral-associated fishes exhibit high levels of habitat specialisation, which can contribute to their susceptibility to habitat loss. However, high levels of habitat partitioning may buffer communities from the loss of particular habitat types. This study provides a quantitative evaluation of habitat specialisation, substratum selectivity and habitat overlap of 9 Eviota (Gobiidae) species in Kimbe Bay, Papua New Guinea. All but 1 locally common Eviota species were strongly associated with scleractinian coral substrata, and species ranged from habitat generalists to obligate coral specialists with some of the most extreme fine-scale patterns of habitat specialisation known for coral reef fishes. Patterns of substratum selectivity varied greatly within the genus, but many species showed distinct preferences for particular corals, most notably the scleractinian genera Acropora and Porites. Most species exhibited low habitat overlap and partitioned habitat on a fine spatial scale, but there were notable exceptions. Two Acropora coral specialists and some species with strong preference for massive Porites coral exhibited high overlap. Overall, the local abundance of Eviota species varied in relation to the degree of habitat specialisation, with the most generalised species more abundant than the habitat specialists. Habitat structure and species-specific differences in habitat specialisation, substratum selectivity and habitat overlap are likely to be key drivers explaining the distribution and abundance of Eviota species and the local community structure. Most importantly, many coral-dependent and less abundant species of Eviota may be vulnerable to habitat loss as a result of the ongoing degradation of coral reefs.

KEY WORDS: Habitat specialisation · Cryptobenthic reef fish · Niche breadth · Live coral · Selectivity · Habitat overlap · Coral reef