The impact of anthropogenic activity on cold-water corals

Abstract

Various human activities can have an impact on cold-water coral (CWC) habitats. Bottom trawling has been shown to degrade these habitats and, in some cases, to cause extensive damage. Among static fishing gears, bottom longlines and gillnets can be set directly on coral grounds. Intensive fishing with these gears, while having much less impacts compared to bottom trawls, may over time cause damage to CWC habitats. Current plans to begin mineral mining activities in the deep sea will pose a risk to CWC habitats due to substrate removal and smothering by toxic particulate waste material. The by-products of oil exploitation, including drill cuttings, drill mud, and wastewater discharge, can impact CWC habitats, for example, causing reduced polyp activity and growth. Effects of accidental oil spills, if occurring in the vicinity of CWC habitats, include partial tissue loss and ultimately death. Litter may affect CWC colonies in a variety of ways, e.g. smothering and entanglement in discarded plastic and lost fishing gear. Submarine cables can exert localized impacts on CWC habitats particularly during their installation, repair, and removal. Potential impacts of CWC exposure to radioactive waste are unknown, but leakages in their vicinity would represent a threat. The impact of increasing CO2-induced global warming and ocean acidification is species-specific. While accurately predicting future effects is difficult, reduced availability of suitable habitats and weaker skeletal strength of reefforming species are to be expected. Evaluating the risk posed by human activities to CWCs remains a challenge, given the remoteness of these habitats.