Evaluating the environmental conditions required for the development of offshore aquaculture: impact on farmed Atlantic salmon health and welfare

Citation

Rey Planellas S & Morro B (2019) Evaluating the environmental conditions required for the development of offshore aquaculture: impact on farmed Atlantic salmon health and welfare [Fish welfare in Off-shore farming]., 07.10.2019-10.10.2019.

Abstract
Scottish salmon is worth over £2 billion to the country’s economy. It is Scotland’s top food export and a particularly valuable product, at about 10% above the world price. Recently, the Scottish Government developed a plan that aims at doubling this production of salmon by 2030. However, a number of factors limit the progress of the industry in its current form, which is based primarily on sea cages in sheltered, fjordic sea lochs where water exchange is restricted. These limitations include the impact of sea lice infestations on fish health (Black 2001), the cost and environmental impact of chemical treatments against the parasite (Costello 2009, SARF 2016, Van Geest 2014), their development of resistance to these treatments (Aaen et al. 2015), planning issues (James & Davies 2010), the (regulatory) Scottish Environment Protection Agency (SEPA) biomass limit of 2500t/site, and the increasing impact of harmful algal blooms (HABs), which can be particularly acute in restricted water exchange environments (Gowen et al. 2012). Moreover, the industry also faces opposition from environmental campaigners who fear that farming in sea lochs might damage wild stocks and the ecosystem. Development of aquaculture in more dispersive “offshore” environments offers a potential solution to some of these problems. Improved, science-based evidence with direct relevance to the complex environment of the west coast of Scotland will permit planning and informed regulation of this offshore transition. The project will address a number of the issues, specifically offshore developments, algal blooms, [sea lice/AGD] host-pathogen interactions and fish health and welfare. These will be addressed through four interconnected work packages: 1) Physical Oceanography, 2) Wave modelling and risk, 3) Hydrodynamic and sea lice/HAB modelling, and 4) Fish health and welfare implications. The latter addresses the particular issue of moving cages offshore and the impact on Atlantic Salmon health and welfare (Kirchhoff et al 2011, Ashley, 2007).