Willemsen compiled survey data from aquaculture operators across the original CRAB Project consortium partners — spanning Norway, Scotland, Ireland, France, Spain, Portugal, and Greece — to produce a granular breakdown of biofouling expenditure by species cultured, geographic region, and management practice. The report employed a standardised cost framework that captured direct expenses (cleaning operations, antifouling products, net replacement) alongside indirect losses (reduced growth, increased mortality, downgraded product quality).
The resulting analysis established the widely cited benchmark that biofouling represents 5 to 10 percent of total production value across European aquaculture. Critically, the report revealed that this percentage varies substantially by context: Mediterranean sea bass and sea bream operations reported costs at the upper end of the range due to year-round fouling pressure, while Norwegian salmon farms clustered around the lower end thanks to seasonal fouling patterns and more established cleaning infrastructure. The cost breakdown by management practice showed that farms relying solely on reactive cleaning spent 30 to 50 percent more than those employing preventive strategies.
Use the biofouling cost calculator to benchmark your operation against the cost ranges documented in this report. The aquaculture farm map shows regional fouling intensity, and the article on what the CRAB Project achieved provides broader context for these findings.