Jackson Estuarine Laboratory

Rapid Assessment Surveys of Fouling and Introduced Seaweeds from Southern Maine to Rhode Island


Rapid assessment surveys (RASs) of fouling and introduced seaweeds were conducted during late July, 2010 and early August, 2013 at multiple marina/harbor sites ranging from southern Maine to Rhode Island. Twenty sites were evaluated during 2010, and 19 in 2013 including 13 of the 2010 sites resurveyed. Based upon a composite of 19 study sites, 99 benthic algal taxa were recorded, including 24 Chlorophyceae, 23 Phaeophyceae, 45 Rhodophyceae, four macroscopic colonial diatoms (Bacillariophyceae), one Xanthophyceae, and two Cyanophyceae or Cyanobacteria. Twenty-seven species (27.3%) were limited to a single site, whereas only three taxa occurred at > 70% of the sites, including Ulva lactuca, Ceramium virgatum, and “Neosiphonia japonica.” Twelve introduced seaweeds were recorded, including one green, two brown, and nine red algae; their probable origins were the Australasia area, Europe, and the northwest and northeast Pacific. “Neosiphonia japonica,” which has recently been delineated within the NW Atlantic, was the most widely distributed adventive taxon, occurring at 100% of the combined nineteen sites, whereas Colpomenia peregrina and Melanosiphon intestinalis were only found at single sites (5.3%). A comparison of the species composition and distributional patterns of introduced seaweed taxa is made between the combined RASs of 2010 and 2013, and the findings of a similar RAS in southern England during 2005. The numbers of total taxa/site recorded at the 19 composite sites varied from 12–31 (mean = 22.0 ± 5.49 SD), with sites north of Cape Cod having slightly higher diversity patterns (i.e., 23.3 ± 5.2 SD) than those to the south (20.8 ± 5.6 SD). An assessment of Cheney's floristic ratios confirmed a wide range of cold- to warm-temperate taxa, as well as reduced numbers of brown algae at some sites, and an overall dominance of red algae. Several opportunistic and fast-growing native species (e.g., Ulva spp.) were also present in many of these highly disturbed habitats.

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New England Botanical Club

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