Bryozoan settlement varies by kelp species
Abstract
Biofouling on kelp by encrusting bryozoans such as Membranipora membranacea can
decrease the commercial value of cultivated kelp by restricting blade size and increasing
breakage. The presence of M. membranacea on three species of Laminarian marine algae –
Saccharina latissima, Costaria costata, and Alaria marginata – was studied in temperate coastal
waters at Friday Harbor Laboratories in Washington State, USA, in May 2021. The settlement at
two depths, over a one-week period, and the abundance of previously settled M. membranacea
were characterized. We hypothesized that settlement of the bryozoan would differ by kelp
species. The results supported our hypothesis. Settlement was highest on S. latissima,
intermediate on C. costata, and lowest on A. marginata. No significant difference in settlement
was detected at 1 versus 3 m. A. marginata is least challenged by issues of biofouling and may
produce chemical defenses to deter epifaunal settlement.