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ALAN 6 will take place from 16-18.06.2020 in Lleida, Spain.

Night Sky Data to the People!

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City Night Time Lapse

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SP09: Light pollution - impact on fish

Impact of artificial light during the night on fish physiology

At the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) subproject 09 dealed with the influence of artificial light at night on the physiology of fishes.

Many different traits and behaviours of fishes throughout their lifetime are somehow influenced by light. Light controls the secretion of several hormones that regulate for example the day-night-rhythm or growth. But also essential processes like reproduction are partly influenced by light. Accordingly, the change of day length causes, together with other factors, the secretion of different sexual steroids and thereby initiates the reproductive phase. For instance, it is well known that eels can be irritated by light during their spawning migration. In commercial aquaculture continuous light is used to enhance growth of fishes by inhibiting the sexual maturation.

Therefore it is most likely, that artificial light at night (light pollution) interferes with several physiological processes.

Perch and roach are two of the most common species in German freshwaters and very have different life histories. The perch is a diurnal predator and the roach is a planctivorous fish that can utilize even low light intensities in the dawn. Using these two fish species, we examined the influence of different nocturnal light levels on hormones that underlie a day-night-rhythm (e.g. melatonin) or a seasonal rhythm (reproductive hormones). After controlled experiments in the lab the results were verified in field experiments.

Scientist is Anika Brüning
Leader of subproject is Prof. Dr. Werner Kloas

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