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HAVBRUK2-Stort program for havbruksforskning

Effects of antifouling copper coating in aquaculture– implications for fish health, performance and sustainability of production

Alternative title: Bruk av kobberimpregnerte nøter i fiskeoppdrettsnæringen– konsekvenser for fiskehelse, bærekraft og produktivitet

Awarded: NOK 12.0 mill.

Project Number:

325849

Application Type:

Project Period:

2021 - 2025

Partner countries:

Norway is a leading ocean economy, with the fish farming industry generating over 68 billion NOKs in revenue in 2019. The aquaculture industry is an important source of jobs, both in the plants and with a ripple effect to the local society. In fact, ca 8000 people were employed in the industry in Norway in 2018. A major challenge in fish farming is the formation of biofouling, i.e organisms and algae growing on fish pen nets. This may compromise water circulation, undermine disease management and cause bacterial diseases to spread in pens. To prevent biofouling, nets are frequently coated with antimicrobial copper alloys, which also results in the release of copper into the surrounding water. Copper released from net coating is considered the largest source of environmental toxicants caused by the fish farming industry, with an estimated 1400 metric tons released into the environment in Norway in 2017 alone. Still, there is little data on how this affects copper concentrations around fish pens. Our project aims to map the extent to which copper is released into the surrounding water and how it is affected by environmental variables and operational procedures. Copper coating also creates an environment in which farmed fish and marine species in the area are subjected to chronic copper exposure. Learning how such practices affects animal welfare is of high value. Moreover, given that copper exposure leads to reduced growth and feed conversion rate, it is of high industrial interest to gain knowledge about copper toxicity. We will employ state-of-the-art methodology to investigate the toxicological effects of copper exposure in Atlantic salmon, as well as how gut bacteria, appetite control, stress, and overall metabolism is affected. We will also investigate how cleaner fish are affected by the practice of copper coating. In sum, this project will provide novel information on the impact of copper-coated fish nets on the sustainability and productivity of fish farming.

To combat the issue of biofouling and biofilm formation, fish pen nettings are frequently coated in copper alloys. To date, there is very limited data on how this practice affects copper concentration in the water in and around fish pens. CAPS therefore aims to map the extent to which copper from antifouling coating is released into the surrounding environment and determine how this is affected by factors such as temperature, salinity, net-rising and duration since last coating. Moreover, while copper coating is an effective approach in preventing biofouling it also creates an environment in which farmed fish and the marine species in the area are subjected to chronic copper exposure. CAPS seeks to determine how chronic exposure to waterborne copper affects the health and welfare of farmed Atlantic salmon and cleaner fish. We hypothesize that copper exposure alters the microbiota composition, and that the altered signaling in the microbiota-gut-brain axis is an important factor underlying the impaired growth observed in fish exposed to waterborne copper. Therefore, we have set up the CAPS consortium to broadly investigate how waterborne copper affects the gut microbiota, the gut-brain signaling, stress, food-intake, growth rate, physiology, and overall metabolism. We will also explore the sub-lethal toxicological effects of copper exposure pertaining to energy metabolism in Atlantic salmon and investigate how cleaner fish, known to feed on crustaceans growing directly on the net, are affected by the practice of copper coating. In sum, this project will provide novel information regarding the impact of copper-coated fish nets on the sustainability and productivity of fish farming. As a result, the CAPS project is of both high environmental, policy and industrial interest.

Funding scheme:

HAVBRUK2-Stort program for havbruksforskning