Chemical Cues and Predation Risk in Aquatic Ecosystems

This overview summarises how aquatic organisms detect, interpret and respond to chemical signals that indicate predation risk and the ways in which these interactions shape behaviour, physiology and community dynamics. Chemical cues released by predators, prey and injured conspecifics provide vital information in environments where visual or acoustic signals may be limited. For example, many fish and invertebrate species reduce foraging activity upon detecting predator kairomones, while amphibian embryos and larvae may hatch prematurely or alter development in response to alarm odours. Such responses can include behavioural shifts, morphological alterations and changes in developmental timing, reflecting adaptive trade-offs between growth and survival. At the community level, these chemically mediated interactions contribute to trophic cascades and influence ecosystem resilience under global change. Recent advances have clarified the mechanisms of cue production and reception, the influence of cue degradation over space and time, and the evolutionary consequences for both prey and predator populations. This field has direct applications for conservation, aquaculture and managing invasive species, by improving predictions of organismal vulnerability and ecosystem response to environmental stressors.

Research from Nature Portfolio

Experiments on marbled crayfish have demonstrated that the presence of predator odours from fish significantly reduces prey feeding rates by up to half, with both kairomones and injured-conspecific alarm cues contributing to this effect. These findings highlight the integration of multiple chemical signals in shaping foraging decisions and the importance of cue origin and concentration. In parallel, studies of tadpole populations exposed to invasive crayfish have revealed rapid evolutionary shifts in developmental rate that override prior local adaptation to temperature gradients. Populations subject to strong predation pressure by non-native predators now develop faster irrespective of climate, illustrating how intense selection can erode intraspecific phenotypic variation. These advances underscore the dynamic nature of predator-prey interactions in aquatic habitats and the role of chemical information in driving both plastic and evolutionary responses.

Chemical Cues and Predation Risk in Aquatic Ecosystems publication trend

The graph below shows the total number of articles in chemical cues and predation risk in aquatic ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Kairomone: A chemical signal emitted by a predator that can be detected by prey, often altering prey behaviour or physiology.

Alarm cue: A chemical substance released by injured or stressed conspecifics that warns nearby individuals of predation risk.

Phenotypic plasticity: The capacity of an organism to modify its development, morphology or behaviour in response to environmental stimuli.

Memory window: The duration over which learned associations, such as predator recognition, are retained following exposure to stimuli.

References

1. Global change and premature hatching of aquatic embryos. Global Change Biology (2024).
2. Feeding in predator naïve crayfish is influenced by cues from a fish predator. Scientific Reports (2023).
3. Uncertainty about old information results in differential predator memory in tadpoles. Proceedings of the Royal Society B (2023).
4. Rapid adaptation to invasive predators overwhelms natural gradients of intraspecific variation. Nature Communications (2020).