Invasion
Invasion Description
1st Records: Nova Scotia/Mahone Bay (1992, Saunders and Metaxas 2007); Nova Scotia/St. Margarets Bay (1992, Saunders and Metaxas 2007)
Geographic Extent
Harbour Breton/Newfoundland/Cabot Strait (2010, Fisheries and Oceans Canada 2011); North Bay/Newfoundland/Fortune Bay (2010, Fisheries and Oceans Canada 2011); Bay l'Argent/Newfoundland/Fortune Bay (2010, Fisheries and Oceans Canada 2011); Baine Harbour/Newfoundland/Placentia Bay (2009, Fisheries and Oceans Canada 2011); Swift Current/Newfoundland/Placentia Bay (2010, Fisheries and Oceans Canada 2011); Placentia/Newfoundland/Placentia Bay (2009, Fisheries and Oceans Canada 2011); Sydney/Nova Scotia/Atlantic Ocean (2008, Lacoursiere-Roussel et al. 2016); Point Tupper/Nova Scotia/Bay of Canso (2008, Choi et al. 2016; Lacoursiere-Roussel et al. 2016); Halifax/Nova Scotia/Halifax Harbour (2008, Choi et al. 2016; Lacoursiere-Roussel et al. 2016); St. Marys/Newfoundland/St. Marys Bay (2010, Fisheries and Oceans Canada 2011); Nova Scotia/Mahone Bay (1992, Saunders and Metaxas 2007); Nova Scotia/St. Margarets Bay (1992, Saunders and Metaxas 2007; Saunders and Metaxas 2010); Cape Sable-Sydney/Nova Scotia/Atlantic Ocean (Watanabe et al. 2009, widely distributed on kelp on ~650 km of shoreline)
Vectors
| Level | Vector |
|---|---|
| Alternate | Natural Dispersal |
| Alternate | Hull Fouling |
| Alternate | Ballast Water |
Regional Impacts
| Ecological Impact | Competition | |
| Fouling by M. membranacea killed kelps (Saccharina longicuris = Laminaria spp.) in St. Margaret's Bay by encrusting the fronds and making them more vulnerable to breakage (Saunders and Metaxas 2008) and decreasing spore production (Saier and Chapman 2004). Membranipora membranacea also out-competed the native bryozoan Electra pilosa when growing on kelps, with faster growth rates. However, on rockweeds (Fucus evanescens-native and F. serratus- introduced), E. pilosa grew more rapidly, and frequently out-competed M. membranacea, whose growth rate was reduced on Fucus spp. In the field, M. membranacea is scarce on F. evanescens and absent on F. serratus, while E. pilosa dominates on both species (Yorke and Metaxas 2011). | ||
| Ecological Impact | Habitat Change | |
| Fouling by M. membranacea results in widespread defoliation of kelps (Laminaria sp., decreasing habitat cover (Saunders and Metaxas 2008; Scheibling and Gagnon 2009). Membranipora mebranacea fouling was positively correlated to an index of summer temperature, while kelp cover was negatively correlated. The mortality of kelp in turn favors the colonization of the kelp beds by the introduced green alga Codium fragile (Scheibling and Gagnon 2006). Bryozoan fouling inhibits grazing on kelp by the snail Lacuna vincta (Banded Chink Shell), resulting in more concentrated grazing on unfouled areas of kelp blades, possibly increasing the risk of the the kelp breaking up. However, no adverse effects on the snail were found (O'Brien et al. 2013). Fouling by M. membranacea greatly increases detrital production in kelp beds (Krumhansl and Scheibling 2011). | ||
| Ecological Impact | Food/Prey | |
| Fouling by M. membranacea greatly increases detrital production in kelp beds (Krumhansl and Scheibling 2011). In addition, kelp encrusted by M. membranacea have a lower absorption efficiency when eaten by sea urchins (Strongylocentrotus droebachiensis), resulting in richer fecal material, and more potential food for microbes (Sauchyn and Scheibling 2009). | ||