A closer look at the effect of aerial root spatial complexity on fish distribution in mangroves

One of the central challenges to field ecologists is to relate structural habitat complexity to the distribution and activity of animals.Predator avoidance is a benefit that juvenile fish can derive from the high spatial... [ view full abstract ]

One of the central challenges to field ecologists is to relate structural habitat complexity to the distribution and activity of animals.Predator avoidance is a benefit that juvenile fish can derive from the high spatial complexity of mangroves. In this study we quantitatively assess the structural complexity of mangroves roots (pneumatophores of Avicennia marina) in southeast Queensland, Australia,using a simple, low-cost, and effective approach based on RGB-D scans (Kinect sensor) and free or readily accessible software. Concomitantly, the distribution and size of fish among roots of the mangrove habitats was captured by underwater cameras.Although structural complexity of the pneumatophores does not have a significant effect on fish distribution, unlike predatory species, the average size of the prey species was slightly higher in more complex root patches. Meanwhile,, prey species spent marginally more time in more complex structures. These results indicate that protection from predators provided by spatial complexity of aerial roots is one of the factors determining the distribution of juvenile fish utilising mangroves as nursery sites.