Thompson, M. John

Dusky jawfish, Opistognathus whitehursti (Longley),
excavate three types of burrows analogous to "open
chamber", "under rock", and "erosion hole" burrows seen
in 0. aurifrons. Burrow type is determined by substrate
conditions at the burrow site. No burrows examined
exceeded 15 cm in depth, and all entrance tunnels were
lined with coral ruhble or shell fragments. Availability
of material to reinforce tunnel and chamber walls is more
important in burrow distribution than actual substrate
particle size. Dusky jawfish initiate burrow construction using
body trunk movements to form a small pit. Mouth burrowing begins when this pit reaches approximately one-third of
the fish's body length. Burrows are completed in five to
six hours. Within colonies, individuals maintain territories
vigorously guarded from conspecifics and smaller fish.
Defense actions may escalate through several steps to
physical contact. A complex color change accompanies
these defense actions.
Female dusky jawfish produce egg masses bound together
by threads arising on individual eggs.