Invasion
Invasion Description
1st Record: Dover Point/NH/Great Bay (1998, McDermott 2000)
Geographic Extent
Dover Point/NH/Great Bay (1998, McDermott 2000); Wentworth Marina, Portsmouth/HN/Great Bay (2006, Harris and Dijkstra 2008); Coastal Marine Lab, Portsmouth/NH/Great Bay (2006, Harris and Dijkstra 2008); Great Bay Marina, Newington/NH/Great Bay (2006, Harris and Dijkstra 2008)
Vectors
| Level | Vector |
|---|---|
| Alternate | Natural Dispersal |
| Alternate | Ballast Water |
| Alternate | Hull Fouling |
Regional Impacts
| Ecological Impact | Predation | |
| In field enclosure experiments (single species trials) at Odiorne Pt., New Hampshire, H. sanguineus fed at lower rates on mussels and snails (Littorina spp.) than C. maenas (Griffen and Byers 2009). Increasing densities of H. sanguineus and the displacement of C. maenas at Odiorne Point are expected to result in increased predation rates in the intertidal community, because predation by H. sanguineus is less affected by intraspecific interference at high density (Griffen and Delaney 2007; Griffen et al. 2008). In laboratory and field mesocosms, H. sanguineus and C. maenas had similar patterns of predation on mussels (M. edulis) and ephemeral algae, but H. sanguineus caused greater declines in barnacles (S. balanoides) (Tyrell et al. 2006). In laboratory experiments, predation of small C. maenas by large H. sanguineus (and vice versa) was common, reducing overall predation rates on other prey, such as amphipods and snails (Griffen and Byers 2006). | ||
| Ecological Impact | Competition | |
| In laboratory experiments, interference between H. sanguineus and C. maenas lowered the predation rates of both species on mussels (Griffen 2006) and amphipods (Griffen and Byers 2006). A similar reduction in predation rates of the two crabs was seen in field enclosure experiments (Griffen and Byers 2009). In enclosure experiments, in the presence of H. sanguineus, C. maenas decreased its consumption of mussels, and did not switch to other foods. On a local spatial scale, within coves at Odiorne Point, a negative correlation was seen in abundance of H. sanguineus and C. maenas (Griffen et al. 2008). At Odiorne Point, a shift in diet, towards algae, was seen in Carcinus maenas, resulting in a decrease in hepatopancreas energy content, and probably a decrease in fecundity (Griffen et al. 2011). | ||