Catch my drift? Between-farm dispersal of biofouling waste from salmon pen net cleaning: Potential risks for fish health

• DOI: 10.1016/j.scitotenv.2024.172464
• Publication Date: 2024-04-15T15:35:07Z
• Authors: Nina Bloecher; Ole Jacob Broch; Emlyn J. Davies; Magnus Oshaug Ped...; Oliver Floerl
• Keywords: Biofouling; Hydroid (botany); Lepeophtheirus; Netting

Biofouling is a serious challenge for global salmon aquaculture and farmers have to regularly clean pen nets avoid impacts on stock health farms' structural integrity. The removed material released into the surrounding environment. This includes cnidarian species such as hydroids, whose nematocyst-bearing fragments can impact gill fish welfare. There also increasing evidence of association parasites pathogens with biofouling organisms cleaning fragments. It unknown whether how far local current regimes disperse this reaches interacts adjacent pens or even neighbouring farms downstream, wild populations in environments. We focussed hydroid Ectopleura larynx, one most abundant Norwegian installations. Using 3D hydrodynamic model parameterised physical biological properties particles (derived via field laboratory studies), we simulated dispersal net waste from two farms. Our results demonstrate that extensively dispersed throughout pens, facilities. Salmon were exposed concentrations up 41-fold elevated compared background concentrations, 30.5 h. Maximum distance was 5.5 km point release, achieved largely within 48 Least-cost calculations show exceeds nearest-neighbour 70 % Norway's (654 farms). study provides some actions taken manage at may affect natural highlight potential risks associated cleaning: harmful particles, pathogens, non-indigenous species, thus underlining need novel farming technologies prevent release potentially waste.