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Bad news for ports and harbours: Lights are attracting ship-damaging creatures

Queue up the Jaws music: But instead of sharks, here come the keel worms, guided by the lights.

Moths aren’t the only creatures attracted to light.

Say hello to the annoying keel worm. If you’re the captain of a cargo or passenger ship, you really don’t want to, because once keel worms attach to your vessel, you’re in for trouble. As the name implies, the worms go for the keel, encrusting it and the hull, like mussels or barnacles on a rock. At best they can slow down the ship; they can even damage it.

And they’re attracted by harbour and marina lights which are essentially guiding them to the ships, according to a story on the BBC website, based on a study published in the Royal Society journal Biology Letters. The story notes that,  ‘Artificial lighting in harbours is attracting sea creatures that damage ships and boats, a study suggests. Scientists believe that the night-time illumination is altering the behaviour of some animals that attach to vessels’ hulls. Keel worms, for example, are lured in by the lights.’

The good news is that the lights are actually driving away some species. The colonial sea squirt, for example, prefers darkness, the study found.

A team of scientists from the University of Exeter and Bangor University concluded that modern LED lighting is largely to blame for altering communities of creatures that attach themselves to hard surfaces and live in seabeds and riverbeds – known as ‘epifaunal’ animals.

‘Our results indicate that ecological light pollution from coastal development, shipping and offshore infrastructure could be changing the composition of marine epifaunal communities,’ the biologists noted in Biology Letters. ‘The recent global surge in LED lighting is increasingly illuminating night-time environments with white light. While these lights hold the potential to reduce expenditure and CO2 emissions, their broad spectral output compared with traditional sodium-based technologies encompasses a greater range of wavelengths to which a variety of light-guided behaviours may be sensitive…

‘The breadth of marine species for which light is an important ecological factor, and its role in guiding broadcast spawning, recruitment, diel vertical migration, communication, navigation and predator–prey interactions  suggest that widespread impacts of artificial light on the structure and function of marine ecosystems may already be occurring.’

Or to put it another way, the lastest knock on LEDs: they’re causing attachment disorder.

Photo is from ssguy via Shutterstock