The development of biofouling communities on pen netting poses significant challenges to the Atlantic salmon ( Salmo salar ) aquaculture industry. Regular cleaning of netting has significant labour and fuel costs attached, while dislodged debris can be harmful to the farmed stock. A better understanding of the biota and the main environmental factors driving community composition is necessary to manage this problem more effectively. This study used a Remotely Operated Vehicle (ROV) to capture images of the in situ biofouling assemblages on multiple pens at two aquaculture sites of differing wave exposure. Sampling was conducted across seasons, at different depths and aspects, with physico-chemical data also collected. Relative wave exposure, water depth and survey month were identified as the main drivers of the biofouling community composition, with key morphospecies identified. A multivariate Generalized Linear Model (GLM) with two latent variables was used to link the abundances of the key morphospecies to the key environmental drivers. Results indicated that the abundance of key morphospecies within a biofouling assemblage is significantly impacted by changes in multiple key environmental drivers, leading to consistent co-occurrences or -absences of morphospecies across sites and seasons. The latent variables indicated that ecological processes or unmeasured environmental factors can also have an effect on the eventual in situ assemblage. This model provides estimates of how the abundance of each key morphospecies is expected to change in different environments. This research can inform industry on how to optimize existing biofouling control strategies using environmental and ecological factors. • Wave exposure, depth and month are the main drivers of biofouling assemblages. • The abundance of several key morphospecies drives overall community composition. • The strength of key environmental drivers differs for each key morphospecies.
Cappaert et al. (2026) studied this question.