Coral reef fish larvae take an active role in selecting their settlement site and
sensory cues may help them to orientate during this process. As settlement is
a period of transition through which the majority of individuals do not survive,
it is often a focal point for the management of coral reef populations, which
are of high conservation concern. In this thesis, I used choice tests and in
situ techniques to assess the response of settlement-stage larvae to a range of
odour, light and acoustic cues and I found that larvae are more selective in
their response to sensory stimuli than previously thought. Micro-habitat odours
are not likely to be used during settlement orientation, and odour cues may be
used to avoid inappropriate settlement sites. The photopositive behaviour of
larval fish is likely to match their spectral sensitivity but this proved difficult to
assess in situ because of the high amount of spatial and temporal variation in
larval distribution. The positive response of settlement-stage fish to played back
reef noise is location specific as well as being highly specific to the reef sound
recording. To understand whether it might be the composition of reef sound that
drives the selective response of larvae to acoustic cues, I took sound recordings
while collecting visual data on fish diversity and the behavioural activity of
a sound producing, or soniferous, fish species. I found that the variation in
intensity of reef noise matches the activity patterns of a soniferous species, and
when reef noise is most intense is when visual estimates on the diversity of
the reef fish assemblage are decreased. This information provides the basis for
understanding how changes in the reef soundscape may effect larval recruitment
and has exciting implications for using sound recordings as a method to monitor
coral reefs. Finally, I tested the viability of releasing reared larvae to boost
depleted populations and found that collecting and holding settlement-stage fish
for a week can increase survival, relative to natural settlement. These data
demonstrate that applying our knowledge of the settlement behaviour of coral
reef fish will make a significant contribution to developing tools for management