Habitat associations of hawkfish: depth, distribution, and density at two sites in Kenya

Abstract

Hawkfish (Actinopterygii: Perciformes: Cirrhitidae) are a family of carnivorous, coral-dwelling fishes. Some of these have been identified as obligate coral-dwelling, facultative coral-dwelling, substratum-dwelling, or water column-dwelling, depending on the species and habitat. Research on hawkfish density and habitat associations has been conducted in the Atlantic, Pacific, and the eastern and central Indian oceans. However, little is known about the density or habitat associations on the coast of East Africa. This study investigates distribution and density patterns of hawkfish species off Kenya, as well as relationships with available coral habitats, at both shallow (<5 m) and deeper (5–15 m) coral reef sites. In addition, habitat associations of the two most abundant hawkfish species of the same genus [Paracirrhites arcatus (Cuvier, 1829) and Paracirrhites forsteri (Schneider, 1801)] are identified. Findings showed species-specific macrohabitat associations, whereby higher densities of P. arcatus were found on deep reefs, and higher densities of P. forsteri were found on shallow reefs. In addition, P. arcatus showed a positive association with the hard-branching coral Pocillopora. However, as there was less Pocillopora on the deep reefs, P. arcatus does not prefer the deep reefs simply because there is more Pocillopora present, lending support that these species are facultative coral dwellers. The increased density of hawkfish on deeper reefs could be an indication of mesopredator release, as the study's deep reef locations were within national reserves, which are open to some types of artisanal fishing, reducing the number of apex predators.