Sponges and corals living in newly discovered underwater fields and meadows are at risk of destruction as they are continuously raked over by halibut fishing boats off the shores of Greenland.
More than a kilometre below the ocean surface, the highly varied ecosystems of the deep sea are home to life forms that thrive on stability. But as fishing boats drag heavy equipment across the ocean floor, they are stirring up chaos in these vulnerable, typically quiet ecosystems. This causes damage that could potentially take decades or centuries to recover from, says Stephen Long at the Zoological Society of London.
鈥淟ife in the deep sea isn鈥檛 used to being disturbed,鈥� says Long.
Advertisement
Long and his colleagues equipped a deep-sea sled with cameras to monitor the sea floor around Greenland, where halibut fishing is a critical economic and cultural mainstay. Halibut (Reinhardtius hippoglossoides) live near the ocean floor, so catching them requires nets stretched between pairs of steel braces that scrape along the sea bottom, at depths of up to 1400 metres.
The researchers found 鈥渆xtensive physical evidence鈥� of trawling on the sea floor, with visible tracks leaving upturned sand and other sediments in frequently trawled areas, says Long. These areas include 鈥渕eadows鈥� of cup corals (Flabellum alabastrum) and fields of wand-like sea pens (Halipteris finmarchica).
This could mean 鈥渟erious or irreversible harm to these deep-sea environments鈥�, says Long.
To minimise the effects on such vulnerable ecosystems, trawling activity should be restricted to certain areas without expanding into untouched deep-sea regions, he says. 鈥淭he best management method is to stick with what鈥檚 already been trawled,鈥� he says.
ICES Journal of Marine Science
Sign up for Wild Wild Life, a free monthly newsletter celebrating the diversity and science of animals, plants and Earth鈥檚 other weird and wonderful inhabitants
