A cost-benefit analysis of four treatment regimes for the invasive tunicate Ciona intestinalis on mussel farms

This study demonstrates the importance of selecting the appropriate treatment regime to maximize productivity and profit in mussel farms affected with the infestation of Ciona intestinalis. This study also showed that the profitability associated to a treatment regime is primarily related to the mussel biomass being harvested. Results indicated that initiating treatment early in the season (July) and treating another 2 or 3 times on a monthly basis had the greatest effect on reducing tunicate numbers and size and enabling greater mussel productivity and farm profitability. Beginning treatment when tunicates are small was also demonstrated to be a significant part of a profitable treatment strategy. While the cost of treatment remains a relatively minor expense, the increase in mussel biomass at harvest, and hence grower profitability are considerably higher.