Ectocarpus species are fine, branching brown algae that grow as tufts 10–60 mm long on virtually any submerged surface. The filaments are uniseriate (one cell thick) and produce both sexual and asexual reproductive structures, enabling rapid population expansion. Ectocarpus is cosmopolitan in temperate seas, found from the Norwegian coast through the Mediterranean, and is typically the first macroalgal fouler to appear after the initial diatom biofilm stage.
Individually, Ectocarpus tufts are easy to remove and add negligible weight. The problem is speed and persistence: filaments regrow within days of cleaning, and dense mats can cover 100 % of a net panel in 2–3 weeks during spring. This algal carpet traps sediment, reduces light penetration, and — more importantly — provides the textured, organic-rich surface that larvae of barnacles, mussels, and hydroids prefer for settlement. Farms that delay cleaning when Ectocarpus first appears often face heavier secondary fouling later in the season.
Net cleaning machines remove Ectocarpus effectively but need to run on a tight schedule — every 1–2 weeks during peak growth. Copper-based coatings suppress settlement for the first several months of deployment. Regular net changes aligned with the spring algal bloom also help. For more on algal foulers and their role in the fouling succession, see the organisms database or review the methods comparison for cleaning frequency guidance.
Control Methods
Net cleaning machines Regular net changes Copper-based coatings