Marine aquaculture sites have huge potential as data providers for climate change assessments

In-situ data is essential in understanding climate change in coastal and marine environments, especially in nearshore locations that are challenging for models to simulate and are often lacking in downscaled climate projections. Environmental parameters such as sea temperature and oxygen are often recorded at fish farms, and this information could be useful for observing coastal changes and climate change assessment. For aquaculture, Norway's BarentsWatch portal is one of the most advanced open-data platforms in the sector. The aim of this study was to inspect the weekly sea temperature data collected from salmon lice monitoring within the Fish Health dataset in BarentsWatch and consider if the recorded temperatures could have value for monitoring climate change due to the spatial and temporal coverage of the farm data. Initial inspection of the dataset found many inconsistencies and suspected errors. In total there were 667 sites where suspected errors were removed. Suspected errors amounted to 7797 data points. Following data cleaning there were 1129 sites and 303,792 data points in total, covering much of the Norwegian coastline. The positions offered good insight into the range of conditions, with data from sheltered inner fjords as well as more exposed locations. Analysis of the BarentsWatch temperatures revealed some sites in southern and western Norway that have already experienced temperatures above 20 °C, challenging conditions for Atlantic salmon (Salmo salar) aquaculture. The results showed differences between sites within the same production regions due to site-specific characteristics, illustrating the need for more local-scale data that represents the actual conditions the fish experience, rather than a reliance on regional averages. Although the BarentsWatch platform provided some insight into the temperatures experienced at Norwegian salmon farms, the lack of standardised reporting and uncertainties about data collection and aggregated values meant that detailed analysis was not possible at present. The BarentsWatch analysis was complemented by data from two farms that further demonstrated the need for better guidance and standardised data collection and reporting. Standardised data collection and reporting would ensure that data from different farms is directly comparable. When considered in context with other conditions and fish health parameters, more standardised and robust monitoring of water temperatures at farms would aid the identification of potential challenging conditions and allow for more targeted adaptation responses. Improved data collection and reporting in the present day would have huge value in the future by facilitating the creation of long-term datasets spanning multiple decades at hundreds of locations along the Norwegian coastline, offering exceptional insight into coastal climate change.