HOLM, E.R.; ORIHUELA, B.; RITTSCHOF, D.; Naval Surface Warfare Center, Carderock Division; Duke University Marine Laboratory; Duke University Marine Laboratory: Genetic variation in adhesive tenacity and adhesive plaque characteristics in the barnacle Balanus amphitrite

Silicone fouling-release coatings represent a reputedly non-toxic alternative to current toxic antifouling coatings, for controlling hull fouling. In contrast to antifouling coatings, fouling-release coatings allow organisms to adhere to the coated surface, but prevent their firm attachment. Ideally, fouling is sloughed from the hull while the ship is underway. Thus, effectiveness of a particular fouling-release coating is not necessarily determined by the rate or extent to which it fouls, but by the ease with which that fouling may be removed. Typically, adhesion strengths (in shear) observed for attached organisms vary both inter- and intraspecifically, and this variation has important consequences for coating performance. In an effort to understand potential biological causes of intraspecific variation, we carried out a quantitative genetic analysis of adhesive tenacity of barnacles Balanus amphitrite attached to a commercially available fouling-release coating. Mean tenacity (removal stress) was 0.092 MPa (SD=0.03); measured values of removal stress spanned an order of magnitude, from 0.018 to 0.189 MPa. Variation in tenacity was weakly influenced by coating thickness, and also by family. The family effects suggested a broad sense heritability for adhesion strength of approximately 0.12. The genetic component, to the phenotypic variation in tenacity, was associated with characteristics of the adhesive plaque. The condition of the adhesive plaque affected removal stress, and also varied significantly among families. Funded by the Office of Naval Research.