Using novel methodologies to examine the impact of artificial light at night on the cortisol stress response in dispersing Atlantic salmon (Salmo salar L.) fry.
Artificial light at night (ALAN) is gaining recognition as having an important anthropogenic impact on the environment, yet the behavioural and physiological impacts of this stressor are largely unknown. This dearth of information is particularly true for freshwater ecosystems, which are already heavily impacted by anthropogenic pressures. Atlantic salmon (Salmo salar L.) is a species of conservation and economic importance whose ecology and behaviour is well studied, making it an ideal model species. Recent investigations have demonstrated that salmon show disrupted behaviour in response to artificial light; however, it is not yet clear which physiological processes are behind the observed behavioural modifications. Here, two novel non-invasive sampling methods were used to examine the cortisol stress response of dispersing salmon fry under different artificial lighting intensities. Fish egg and embryos were reared under differing ALAN intensities and individual measures of stress were subsequently taken from dispersing fry using static sampling, whereas population-level measures were achieved using deployed passive samplers. Dispersing fry exposed to experimental confinement showed elevated cortisol levels, indicating the capacity to mount a stress response at this early stage in ontogenesis. However, only one of the two methods for sampling cortisol used in this study indicated that ALAN may act as a stressor to dispersing salmon fry. As such, a cortisol-mediated response to light was not strongly supported. Furthermore, the efficacy of the two non-invasive methodologies used in this study is, subject to further validation, indicative of them proving useful in future ecological studies.
School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK; Centre for Environment, Fisheries and Aquaculture Science, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK.
Rhian C
RC
Newman
Centre for Environment, Fisheries and Aquaculture Science, The Nothe, Barrack Road, Weymouth, Dorset DT4 8UB, UK.
Tim
T
Ellis
Centre for Environment, Fisheries and Aquaculture Science, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK.
Phil I
PI
Davison
Centre for Environment, Fisheries and Aquaculture Science, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK.
Mark J
MJ
Ives
School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
Rob J
RJ
Thomas
School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
Sian W
SW
Griffiths
Centre for Environment, Fisheries and Aquaculture Science, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK.
William D
WD
Riley
Artificial light at night; Atlantic salmon; cortisol