Guenther, Misimi, and Sunde conducted a twelve-month monitoring programme at salmon farm sites in Norwegian fjords, sampling fouling communities on cage nets at monthly intervals to map the complete seasonal succession of colonising organisms. The study employed both biomass quantification and taxonomic identification to track how the fouling community developed from initial net deployment through to the end of the production cycle.
The data showed a consistent successional pattern across sites: colonial hydroids (principally Ectopleura larynx) dominated the initial colonisation phase from May through July, rapidly covering net surfaces within two to four weeks of deployment. From midsummer onward, blue mussels (Mytilus edulis) progressively displaced the hydroid community, and by autumn, mussels and barnacles (Balanus crenatus) together constituted over 80 percent of fouling biomass. This succession pattern has direct management implications, as the dominant fouler determines the appropriate cleaning method and frequency.
Farmers can identify the key fouling species at their sites using the fouling organisms database and plan cleaning schedules around the seasonal peaks documented here — the regional fouling calendar provides site-specific timing. For guidance on cleaning methods suited to different community types, see the solutions comparison tool.