Fucus vesiculosus (bladderwrack) is a facultative epiphyte on Ascophyllum nodosum (rockweed) in the Gulf of Maine’s rocky intertidal zone
Year: 2025
Type: article
Abstract: Epiphytes that grow on marine macroalgae can be detrimental to their host species but may also serve as a habitat and food source for invertebrates. Here, we report facultative epiphytism involving a common fucoid, Fucus vesiculosus (bladderwrack), that attaches to its primary competitor. The host species, Ascophyllum nodosum (rockweed), is a large, dominant seaweed in rocky intertidal communities of the Gulf of Maine. A. nodosum co-occurs with epilithic F. vesiculosus , a faster-growing fucoid that survives better at wave-exposed sites. Epilithic Fucus is typically shaded out by Ascophyllum in more sheltered areas. These species often grow intermixed, yet previous studies have not documented the frequent presence of Fucus as an epiphyte on Ascophyllum . We sampled epiphytic Fucus growing on Ascophyllum at 9 sites ranging from Gloucester, Massachusetts, to Grand Manan Island, New Brunswick. We collected 20-36 Fucus epiphytes per site and recorded their length, dry weight, and reproductive status. At the 2 most exposed sites, epiphytes were relatively small and only ~25% were reproductive. At 6 other sites, we found a continuum of epiphyte size classes, and 27-54% were reproductive. The largest epiphytic Fucus individuals at these sites ranged from ~20-60 g dry weight and were >40 cm in length. In contrast, some Fucus epiphytes in Trescott, Maine, were extremely large (>150 g and >50 cm long), and 67% were reproductive. These epiphytes are a common feature of Ascophyllum stands, allowing F. vesiculosus to expand its typical niche within the intertidal zone by adhering to its larger competitor.
Source: Marine Ecology Progress Series
DOI: 10.3354/meps15055
Authors: Allison A. Snow, David Porter, Nancy K. Prentiss
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Life below water
Open Access status: hybrid
OpenAlex ID: W4417106347