Enhanced fast-start performance and anti-predator behaviour in a coral reef fish in response to suspended sediment exposure

Abstract

Declining water quality, in particular elevated suspended sediments, pose a significant threat to coastal coral reefs. We exposed juvenile anemonefish (Amphiprion melanopus) to two suspended sediment concentrations (0 or 180 mgL-1) for 7 days and examined their predator escape performance and anti-predator behaviour in both clear water and suspended sediments (0 and 180 mgL-1 , i.e., acute exposure). After 7-day exposure to suspended sediments, fish responded faster to a mechanical stimulus and exhibited enhanced fast starts compared to individuals reared in clear water, regardless of acute exposure. Fish were also less active and avoided open areas when exposed to elevated suspended sediments in the test arena when compared to clear water, irrespective of prior 7-day exposure. While these changes are likely strategies to compensate for an increased perceived predation risk in suspended sediments, they may also be associated with non-consumptive costs for juveniles living on turbid reefs.

Fear effects associated with predator presence and habitat structure interact to alter herbivory on coral reefs

“…Furthermore, high turbidity has recently been shown to lead to increased vigilance (i.e. more cautious behaviour) and decreased activity in coral reef fish [10] that could potentially reduce foraging rates [28]. Our results suggest that herbivorous fishes' perception of risk is not necessarily additive-the presence of a predator may not significantly change feeding behaviour of the dominant browser, if perception of risk is already high, since increased vigilance may result in fitness costs [29].…”

“…The nature and magnitude of fear effects can be influenced by a range of factors, including predator identity [9], prey attributes [5], habitat characteristics [6,7] and physical environmental conditions (e.g. water quality [10]). Fear effects will, therefore, vary spatially and temporally [2,4,7,9], and are often heavily dependent on ecological context (e.g.…”

Insights from extreme coral reefs in a changing world

“…Terrigenous run-off is typically accompanied by a multitude of anthropogenic pollutants (nutrients, pathogens, pesticides, insecticides, oil, waste, sewage) that are known to have deleterious effects on corals and associated fish and invertebrate biota (Field et al 2007;Stender et al 2014;Hess et al 2017;Johansen et al 2017) and has been correlated with severely reduced fish abundance and yields on affected reefs (including loss of corals and herbivores typically seen as critical for a productive and resilient ecosystem) (Mallela et al 2007;DeMartini et al 2013;Jokiel et al 2014). Our current limited understanding shows suspended sediment to impair vision and olfaction in fishes looking for shelter and food (Wenger et al 2011(Wenger et al , 2012, and their response to predators (Bauman et al 2019;Hess et al 2019). Gill damage may occur after shortterm sediment exposure and bacterial and pathogens may accumulate on the gills (Au et al 2004) and limit capacity to extract oxygen needed to support high energetic demands (Hess et al 2015).…”

Sensory environment affects Icelandic threespine stickleback's anti-predator escape behaviour

“…These analyses support a reduction in fast start and increase in freezing behaviour in putatively derived highland populations. Frequent fast start behaviour is associated with high levels of perceived predation risk and is energetically costly both directly (reduced foraging time) and indirectly (high stress) [ 32 , 33 ]. The harsh conditions experienced in the highlands, with a very short period where lakes are not frozen, likely select for very fine-tuned and less energy-demanding anti-predator behaviour in these populations.…”