We discovered that, unlike most other locations, predation of juvenile reef fish at Ningaloo Reef is concentrated during mid-afternoon times, instead of the normal dusk/dawn periods. We also found an unexpected candidate for the top predator of juvenile fish at Ningaloo Reef…... In fact, of all the predatory strikes we seen on the videos, the moon wrasse was responsible for over 75% of them! The interest of the moon wrasse towards the juvenile fish was highlighted by them spending significantly longer around the patches ‘fertilized’ with juvenile fish compared with control patches with no juveniles.
To do this, we “fertilised” some coral patches with juvenile reef fish while leaving others untouched (i.e. no juvenile reef fish), and filmed what happened over the course of the day! We even used special lights to allow us to see what was happening during the first couple of hours of darkness! We ended up with 199 hours of video recordings, where we identified all fish within 30cm of the patch, measured how long they spent within the vicinity and whether or not they tried to eat one of the juveniles!
Just like artificial reef fishing we need to be sure that we do not right on top of the structure here. But, in this case it becomes more important. This is a natural reef formation, and an anchor can do irreparable damage when dropped right into the formation.
I do not suggest renting boat and fishing reefs over unfamiliar waters. Reef fishing is for experienced captains, hire a guide in waters you are not familiar with.