The functional role of tabular structures for large reef fishes: avoiding predators or solar irradiance?

Competition for shelter in a high-diversity system: structure use by large reef fishes

“…In order to reduce complexity, dominance relationships are not shown for species in nonadjacent ranks when transitive connections exist via other species in the hierarchy Coral Reefs this structure imply that there are significant benefits from sheltering under tabular structures. Notably, access to shade is likely to moderate energetic expenditure that would otherwise be required to deal with harmful UV irradiance (Kerry and Bellwood 2015), although these costs need to be formally evaluated.…”

“…The physical position of dominant capuchin monkeys (Robinson 1981) and feral pony mares (Rutberg and Greenberg 1990) within their groups are thought to provide them with increased feeding opportunities and reduced predation vulnerability. For sheltering large reef fishes, position under tabular structure may affect predation vulnerability, field of vision, and photopic acclimation in case a sudden escape into open water is required (Kerry and Bellwood 2015). Moreover, fishes sheltering under a tabular structure may tolerate each other because they gain a defence against predation by having multiple sets of eyes watching for any approaching threat (Eckardt and Zuberbühler 2004).…”

“…Video footage was analysed from 1100 to 1400 h, after 1 h of 'soak' time to allow fishes to recover from diver disturbance (Dickens et al 2011) and acclimate to the presence of the camera. Furthermore, this window of observation was selected because usage of tabular structures by large reef fishes reaches a peak during the period when the sun is highest in the sky (Kerry and Bellwood 2015) and this increased density of fishes is likely to increase competition for the resource (Holbrook and Schmitt 2002;Hixon and Jones 2005). Such competition may display elements of both interference and exploitation.…”

“…Multiple species of large reef fishes seek access to the Communicated by Ecology Editor Dr. Alastair Harborne understorey of these structures in shallow coral reef environments, and have been observed to leave areas where tabular structures are lost (Kerry and Bellwood 2014). This behaviour may be explained by the dependence of large reef fishes on tabular structures to avoid UV irradiance (Kerry and Bellwood 2015), which can be extreme in shallow coral reef environments, and has been shown to cause severe skin damage and melanomas on fishes (Sweet et al 2012;Zamzow et al 2013). Intense use of tabular structures by large reef fishes during peak sunlight hours (Kerry and Bellwood 2015) suggests that fish compete for space, but this has not been demonstrated.…”

“…This behaviour may be explained by the dependence of large reef fishes on tabular structures to avoid UV irradiance (Kerry and Bellwood 2015), which can be extreme in shallow coral reef environments, and has been shown to cause severe skin damage and melanomas on fishes (Sweet et al 2012;Zamzow et al 2013). Intense use of tabular structures by large reef fishes during peak sunlight hours (Kerry and Bellwood 2015) suggests that fish compete for space, but this has not been demonstrated. This presents a unique opportunity to study competition in a species-rich environment for a limited resource, shelter.…”