EPA - Ireland's Environment, An Integrated Assessment - 2020

Ireland’s Environment – An Integrated Assessment 2020 Underwater Noise Anthropogenic underwater noise can interfere with the navigation, communication and prey location of marine mammals, but is not considered a significant threat in most of Ireland’s marine waters. Anthropogenic underwater noise related to vessel movement, seismic surveys, drilling, use of sonar, pile driving, underwater explosions and dredging has increased as these sectors expand. This noise can interfere with the habitat condition, navigation, communication and prey location of marine animals up to tens of kilometres from the noise source. Recent research on underwater noise has produced noise risk maps for high-, medium- and low-frequency cetacean groups (Sutton et al. , 2014). A map of shipping noise has been produced by the UK Centre for Environment, Fisheries and Aquaculture Science (CEFAS) for Irish and UK waters (Farcas, et al. , 2020). This indicates that the areas with the greatest shipping noise in Irish waters are located on the south-west and north-east coasts of Ireland (Figure 8.5). The levels of impulsive underwater noise-causing activities within Ireland’s maritime area were considered low during 2016- 2018 and Good Environmental Status is currently being achieved (DHPLG, 2020), although gaps in knowledge on the impacts of this pressure are acknowledged. Work continues through the EU Technical Group on Noise and the OSPAR Group on Noise to address the knowledge gaps and to create harmonised assessments and standards. Figure 8.5  Map of shipping noise produced by CEFAS. The map was produced using data captured by microphones placed on the seabed (Farcas et al. , 2020). Annual P50 total noise; colour scale shows sound pressure level in units of dB re 1 μPa Seaweed Harvesting Traditional hand harvesting of intertidal seaweed takes place in Ireland but interest in mechanical harvesting has increased. Traditional seaweed harvesting and processing has been carried out on the west coast of Ireland for many centuries. This involves the collection of bladder wrack ( Ascophyllum nodosum) at low tide with the use of sickles, knives and, in some cases, rakes. Local harvesters leave a section of the root to ensure that this renewable resource is maintained. Currently, in areas where existing rights to harvest are in place, seaweed harvesting licences cannot be given to new applicants. 17 While traditional harvesting has generally been focused on intertidal wrack species, more recently interest in using mechanical means to harvest subtidal kelp communities has increased. Additional pressures on habitats and marine biodiversity and loss of storm surge protection are associated with mechanical harvesting (Smale et al. , 2013). KelpRes 18 is a recently funded project that will investigate the diversity and resilience of these ecosystems in Ireland. 17 https://www.housing.gov.ie/planning/foreshore/minister-english- clarifies-legal-position-around-seaweed-harvesting-and 18 http://www.nuigalway.ie/zoology/research/kelpres/ 206