A Brazilian non-governmental organisation, Fiotrar, has deployed sausage-shaped filters packed with human hair along the Bom Jesus inlet in Guanabara Bay (a large coastal bay adjoining Rio de Janeiro, long burdened by industrial and shipping pollution) to absorb oil and other contaminants before they reach fragile mangrove ecosystems. The filters, supplied with clippings collected from ten participating hair salons in Rio, can remain in the water for up to four months and exploit hair's natural absorbency — each gram capable of soaking up five grams of oil. The initiative matters for the bay's traditional fishing communities, whose catches have declined sharply due to surface oil that affects marine life down to 1.5 metres below the waterline, and for biodiversity more broadly, as pollution has reduced the bay's crab species from 20 to just seven in affected mangrove zones.