Ireland's State of the Environment Report 2024

229 Chapter 9: The Marine Environment Aquaculture The Irish aquaculture sector’s output in 2022 was worth €196 million and mainly consisted of oysters, mussels and salmon production (BIM, 2023a) (Figure 9.11). Figure 9.11  National total tonnage of Irish aquaculture output, 2012-2021 20000 25000 30000 35000 40000 45000 50000 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 Year Tonnes Source: BIM, 2023a 4 www.dublinport.ie/masterplan/mp2/ (accessed 2 May 2024). Aquaculture operations can potentially affect the marine environment, such as through escaped farmed salmon, the spread of pathogens and parasites to native populations, and the potential disturbance to and displacement of fish, shellfish, birds and other wildlife populations. The accidental introduction of non-native species, together with water pollution, aquaculture and other activities, is considered a pressure for a number of protected habitats (NPWS, 2019; OSPAR, 2021d; ICES, 2022a). Aquaculture is also at risk of environmental pressures. Ireland has 64 designated shellfish growing areas, which have specified water quality requirements to support shellfish production. The risks from pollution risks to shellfish production and environmental health are discussed in Chapter 14. Dredging and dumping at sea The removal of seabed material for maintenance and navigational purposes is a common occurrence in ports and harbours around Ireland. The disposal of this dredged material at sea can only occur under a Dumping at Sea Permit granted by the EPA. Such permits are also required for the removal and dumping of dredged material to facilitate infrastructural expansion (capital projects). Permit returns show that, in 2023, approximately 1.3 million tonnes (wet weight) of material, arising mainly from maintenance projects, were dredged and deposited at eight licensed disposal sites around the Irish coast. In Dublin Port, capital works commenced as part of the MP2 Project 4 which is being carried out under Dublin Port’s Masterplan 2040 to increase the port capacity. The permitting process ensures that dumping is a localised pressure and contaminated sediments are not dumped at sea. Assessments under the MSFD indicate that dumping is not having widespread or long-term effects on the wider ecosystem. Underwater noise Sound is a by-product of human activities in the marine environment (e.g. shipping or construction) or is produced intentionally for the purposes of surveying the seabed or water column. Sound is referred to as ‘noise’ only when it has the potential to cause negative impacts on marine life. Anthropogenic sound sources are categorised as impulsive or continuous. A recent OSPAR assessment looked at impulsive sound sources in the North Sea area, which include percussive pile driving for inshore and offshore construction, seismic surveys to map subsea oil and gas deposits, explosions and some sonar sources (OSPAR, 2023c). This has shown that impulsive sound sources have caused temporary displacement of small cetaceans (e.g. harbour porpoise), increased physiological stress in some fish species (e.g. European seabass) and caused developmental abnormalities in invertebrate larvae. In some cases, they may also be capable of causing more severe effects such as permanent auditory damage or blast injuries.