of artificial lighting - 'Fish' ecosystem destruction
In the case of fish,
there are fish species that gather in the light, and fish that avoid light, and
excessive light interferes with growth and spawning, or induces excessive spawning.
The fish with regurgitated instincts such as salmon and herring are relying on
the lights to feed the carnivorous species because of night lighting.
Freshwater fish, canary, and green hydra are also gathered in the light, making
it easy for the captor to feed. (Fig.1)
Teleost fish reaction to light stimulus
depends upon fish physiologic adaptation to ambient light levels prior to
exposure to light level changes. Laboratory studies examining the use of
artificial light to guide juvenile salmon through migration barriers report
measurable differences in fish responses to variations in the quantity and
quality of artificial light.
According to Barbara nightingale and
Charles simenstad, University of Washington, studies in the Pacific Northwest
report potential changes in fish migration behavior and the distribution of
fishes in night-lighted areas. Such changes potentially increase mortality
risks for salmon, herring, and sand lance. Juvenile chum and their predators,
such as hake, dogfish, sculpin, large chinook, and coho, appear to congregate
below night security lights with increased light intensities attracting the
chum and potentially delaying outmigration. The potential changes in species
abundance and dominance resulting from increased prey access under artificial lighting
also warrant further exploration. (Fig.2)
Fig.2. Lights along rivers and streams can
disrupt predator–prey interactions, such as seals hunting salmon under lights.
Here, an artificial lighting is causing
confusion in the fish ecosystem. It should not be forgotten that a fish
ecosystem damaged by light pollution can cause human food problems.