COLOR MORPH-HABITAT RELATIONS IN THE ARC-EYE HAWKFISH PARACIRRHITES ARCATUS (PISCES, CIRRHITIDAE)

The arc-eye hawkfish Paracirrhites arcatus, like other congeners, has multiple color morphs whose relative abundances vary greatly among geo graphic locations, To gain insight into the environmental factors that potentially influence the morph distributions of this species, we con ducted two series of surveys at different spatial scales. One extensiv e, broad-scale survey of 165 central, south, and western Pacific sites was conducted over a 9-yr period (1986-1993), Another series of sites , located along an exposure gradient on the leeward coast of the Islan d of Hawaii, was surveyed intensively during 1990-1994. Both surveys r evealed that relative abundances of the species' two most common (whit e-striped, WS; melanistic, MEL) color morphs were independent of micro habitat, body size, or adult sex. Morph frequencies were, however, gen erally related to bottom depth. Across Oceania, the WS morph was more common at depths > 10 m over a depth range of 1-27 m. At Hawaii, the W S morph increased in abundance at depths > 8 m over a range of 1-12 m and was relatively common at 1-4 m depths wherever frequently used bra nching corals (Pocillopora meandrina) were scarce. Patterns of color m orph frequencies in P. arcatus may represent trade-offs between intras pecific communication and predation risk that exist at differing coral and fish densities. We also discuss morph distributions more generall y relative to patterns observed for other, perhaps analogous polychrom atisms in reef fishes.