Cryptobenthic fish assemblages across the coral reef− seagrass continuum in SE Sulawesi, Indonesia

Cryptobenthic fishes have a significant influence on coral reef ecosystem dynamics; however, they have received considerably less attention than their larger, more conspicuous fish counterparts. In nearby seagrass zones, there is little or no information about cryptobenthic fishes, even for basic parameters such as density and distribution, although smaller organisms may have a substantial effect on ecosystem processes. The present study investigated cryptobenthic fish distribution and microhabitat use in the coral reef−seagrass continuum in SE Sulawesi, Indonesia. Cryptobenthic fishes were sampled from dominant microhabitats in 3 zones — reef flat, bommie, and seagrass beds. Abundance and diversity of cryptobenthic fishes within microhabitats of each zone were comparable. Consequently, they are likely an important food resource for predatory transient and resident fishes in the seagrass and bommie zones, and could influence ecosystem dynamics in a manner observed on coral reefs. In addition, there were no clear differences between fish microhabitat use and assemblage structure across zones. This suggests microhabitat availability is the key determinant of cryptobenthic fish distribution throughout the coral reef− seagrass continuum, despite the changes in biological and physical conditions among the zones. Lastly, this research provides, for the first time, initial estimates of density and diversity of cryptobenthic fishes along the coral reef−seagrass gradient within the Coral Triangle.