Effects of antifouling copper coating in aquaculture – implications for fish health, performance and sustainability of production
The project in a nut shell
Norway is a leading ocean economy, with the fish farming industry generating over 68 billion NOKs in revenue via local consumption and export in 2019. The aquaculture industry is an important source of jobs, both primarily in the plants and with a ripple effect to the local society. In fact, ca 8000 people were employed in the aquaculture industry in Norway in 2018 (SSB).
One of the challenges in fish farming operations is the formation of biofouling, i.e organisms and algae growing on fish pen nets. This may compromise water circulation, undermine disease management protocols and cause bacterial diseases to spread in fish pens. To prevent biofouling, the nets are frequently coated with antimicrobial copper alloys. While this is an effective approach in preventing biofouling it also results in the release of copper into the surrounding water. The copper released from fish net coating is in fact considered the largest source of environmental toxicants caused by the fish farming industry, with an estimated 1400 metric tons of copper released into the environment from copper coated fish nets in Norway in 2017 alone. Still, there is very little data on how this practice affects copper concentrations around the fish pens. As a first step our project aims to map the extent to which copper is released into the surrounding water and how the release is affected by environmental variables and operational procedures (change of nets and net-cleaning).
The copper coating also creates an environment in which farmed fish and the marine species in the area are subjected to some level of chronic copper exposure. Learning how such practices affect animal welfare is of high value in its own right. Moreover, given that an often-observed effect of copper exposure is reduced growth and feed conversion rate, it is of high industrial interest to gain knowledge regarding 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, food-intake, 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 regarding the impact of copper-coated fish nets on the sustainability and productivity of fish farming.
CAPS will systematically determine the extent to which copper-coated fish pens impact copper concentrations in the surrounding aquatic environment, and the effects of this on the microbiota, farmed Atlantic salmon and cleaner fish. The study is the first of its kind and will form a knowledge basis to better understand the consequences of antifouling copper coating as an industry practice. The interdisciplinary nature of the project allows for an holistic approach to understanding the issues related to copper coating while using highly specialized state-of-the-art methodology. As such, the novelty of the project lies not only within its implications, but also its approach and its methodology.
Regardless of results, CAPS will provide information on the environmental and direct effects of antifouling copper coating on aquatic animals, including fish in culture. These insights will be valuable in the ongoing debate regarding animal welfare and economic consequences of aquaculture practices. CAPS will also provide novel information regarding interplay between gut microbiota and the gut-brain metabolic signaling. The potential impact from such basic knowledge is only limited by the innovation- and research effort that follows. Knowledge about gut microbiota in mammals has been key to unlocking information about feeding behavior, digestive/ absorptive processes, metabolism, and immune response, with repercussions on energy homeostasis and health of the host
By providing documentation on the effect of Cu coating on the surrounding environment, animal health, sustainability, productivity and profitability of fish farming, this project will contribute to knowledge-based developments, strategies, and legislation. As such, its outputs will contribute to several UN sustainable development goals, including goal 8, which is to "promote sustained, inclusive and sustainable economic growth, full and productive employment and decent work for all" and goal 14, which is to "conserve and sustainably use the oceans, seas and marine resources for sustainable development"
The consortium partners have been carefully selected to provide complimentary competence that gives important synergy and added value to the research carried out by the individual partners. The collaboration allows the partners to conduct research on a grander scope, which is hugely beneficial to each of the partners, a major advantage for research in general, and key in the development of sustainable aquaculture.