Clownfish may look like coral reefs ' natural entertainer , but they do n’t like being in the spotlight . It appears their unsure nature poke out to their hatching , as they wo n’t even lead their eggs if the lights are too bright . This means coastal developments , often accompanied by a lot of visible light spilling into coastal urine , could be a threat to clownfish , and quite likely most other manikin of reef fish as well .
It ’s well known that coral reefs are under threat from uprise temperatures , sea acidification , overfishing , and runoff from the shores . Dr Emily Fobertof Flinders University wondered if there might be an additional danger we ’ve been lose – light contamination , which she call ALAN , or Artificial Light At Night .
“ There is a mass of research on the effects of ALAN on terrestrial organism , ” Fobert told IFLScience , “ but very niggling look at the impact on the marine environment . I found that surprising because fish are not immune to exposure to lighting . ” Fobert is aware of two studies on the effects of ALAN on Pisces the Fishes , but both are on behavior such as scrounge , not reproduction .
Fobert decide to essay clownfish because “ they are site - specific . If they have settle in one localization and they are expose to spark , they will not move away . ”
When Fobert shine 21 lux onto the surface of the urine beneath which clownfish were hold out , she found none of their egg think of . However , a batch in the same conditions , sluttish photo aside , think of ordinarily , she reported inBiology Letters . Fobert told IFLScience it is common for lights on piers to shine 200 lux of light onto the weewee below them and 21 is a buttoned-down estimation of the exposure reefs cheeseparing to tourist establishments can be exposed to .
With sufficient awareness of the problem , this may be a much easier problem to resolve than many of the other threat coral reefs face . Fobert ’s study was done with relatively bluish light-emitting diode lights , which penetrate the water more than long wavelengths . She ’s presently doing a follow - up work using heater - colored source , but does not yet have the termination to see how much it helps . However , she noted that on land , the personal effects on many species can be minimized by changing wavelengths .
Other alternatives let in switching off coastal light for a few nighttime a month or several hours a dark . Fobert is hopeful on the latter , noting that many reef fish hatch a few hour after sundown and therefore might not need a whole night of darkness to leave their scale .
One way or another , we ’ll probably need to make some change if we want to keep finding Nemo snug to holiday web site .
