Invasion
Invasion Description
1st record: Sagamore, MA/Cape Cod Bay at the east end of the Cape Cod Canal (1994, McDermott 1998).
Occurrences north of Casco Bay may not represent established, locally reproducing populations, because summer temperatures are too cool (mean temperature below 13 C) to support sucessful larval development. These occurrences may depend on larvae transported from the south (Stephensen et al. 2009). In a 2007 survey, settling crabs were not found in collectors north of 43.081 N latitude (Great Bay NH). These results were consistent with a model incorporating dispersal, larval development, and environmental conditions (Delaney et al. 2012).
Geographic Extent
Shleburne/Nova/ Scotia./St. Marys Bay (2020,WCITTMO 2022, 43.7633° N, 65.3235°(; WGleason Point town park, Perry/ME/Passamaquoddy Bay (3/10/2020, USGS Nonindigenous Aquatic Species Program 2021); Petit Manan National Wildlife Refuge, Steuben/ME/Dyer Bay (2015, Lord and Williams 2016); Schoodic Point/ME/Frenchman Bay (2005, Delaney et al. 2008); Moores Harbor, Isle au Haut/ME/Gulf of Maine (2003, Delaney et al. 2008); Owls Head/ME/Penobscott Bay (2002, USGS Nonindigenous Aquatic Species Program 2008; 2015, Lord and Williams 2016); Lincoln County/ME/Muscongus Bay (2001, USGS Nonindigenous Aquatic Species Program 2008); Bristol/ME/Muscongus Bay (2015, Lord and Williams 2016); Freeport/ME/Casco Bay (2009, McNaught and Norden 2011, recruits on collectors); Portland area/ME/Casco Bay (2001, USGS Nonindigenous Aquatic Species Program 2008); Orrs Island/ME/Casco Bay (2001, USGS Nonindigenous Aquatic Species Program 2008); Cape Elizabeth/ME/Gulf of Maine (2015, Lord and Williams 2016); Scarborough/ME/Gulf of Maine (2001, USGS Nonindigenous Aquatic Species Program 2008); Kennebunk Beach/ME/Gulf of Maine (7/14/2008, MIT Sea Grant 2011); Biddeford/ME/Biddeford Pool (8/22/2008, MIT Sea Grant 2011; 2015, Lord and Williams 2016); Wells/ME/Wells Harbor (2009, MIT Sea Grant 2011); York/ME/York Harbor (2005, USGS Nonindigenous Aquatic Species Program 2008); Dover Point/NH/Great Bay (1998, McDermott 2000); Seapoint, Kittery/ME/ Gulf of Maine (2015, Lord and Williams 2016); Wentworth Marina, Portsmouth/NH/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); Rye/NH/Gulf of Maine (1999, McDermott 2000; 2015, Lord and Williams 2016); North Hampton, approximately 10 km south of Odiorne State Park/NH/Gulf of Maine (1998, McDermott 2000); Emerson Rocks, Plum Island/MA/Gulf of Maine (2009, MIT Sea Grant 2011); Halibut Point State Park, Rockport (2003, MIT Sea Grant 2003); Gloucester/MA/Gloucester Harbor, Massachusetts Bay (1999, USGS Nonindigenous Aquatic Species Program 2008); Deer Island, Winthrop/MA/Boston Harbor (2000, MIT Sea Grant 2003); Boston Harbor Islands/MA/Boston Harbor (Bell et al. 2005); Black Falcon Terminal, Boston/MA/Boston Harbor (2000, MIT Sea Grant 2008); Nahant/MA/Dorothy Cove, Baillie and Grabowsi 2018 (42 250N, 70 550W); Scituate/MA/Massachusetts Bay (1999, O'Connor 2013); Marshfield/MA/Green Harbor (Cape Cod Bay) (1994, McDermott 1998; O'Connor 2013); Manomet Point, Plymouth (1998, Whitlatch and Osman 2000); Sagamore, MA/Cape Cod Bay at the east end of the Cape Cod Canal (1994, McDermott 1998); Welfleet/MA/Cape Cod Bay (1996, McDermott 2000)
Vectors
| Level | Vector |
|---|---|
| Probable | Natural Dispersal |
| Alternate | Canal |
| Alternate | Ballast Water |
| Alternate | Hull Fouling |
Regional Impacts
| Ecological Impact | Predation | |
| Concomitant with a steady increase in abundance of H. sanguineus, a decline in abundance of C. maenas and a scarcity or absence of small juveniles was seen at Point Judith in 1996-1999 (Lohrer and Whitlatch 2002). The replacement of C. maenas by H. sanguineus in rocky intertidal regions of Southern New England (Long Island to Cape Ann) has resulted in a likely increase in predation rates, due to much higher population densities of H. sanguineus (field survey, seen in Narragansett Bay, RI) (Griffen and Delaney 2007). In experimental feeding trials using M. edulis, H. sanguineus was found to feed at higher rates than individuals of Carcinus maenas (Green Crabs) of equal weight (de Graff and Tyrrel 2004). However, in field enclosure experiments (single species trials) at Odiorne Pt., New Hampshire, H. sanguineus fed at lower rates per capita on mussels and snails (Littorina spp.) than C. maenas, due to their smaller average body size (Griffen and Byers 2009). 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). In laboratory trials, in which Hemigrapsus sanguineus were given alternate food (mussels) and shelter, adult H. sanguineus preyed on juvenile American Lobsters (Homarus americanus with a 11-14 mm carapace length) (Demeo and Riley 2006). ;Experiments and modeling indicate that predation by Carcinus maenas and Hemigrapsus sanguineus is likely to reduce the use of intertidal habitats by the native Cancer irroratus (Rock Crab) in the Gulf of Maine (Griffen and Riley 2015). Caging experiments indicate that intraguild predation by adult Hemigrapsus sanguineus has decreased recruitment of Carcinus maenas in Massachusetts Bay, but variation iun recruitment with depth and season has enabled C. amenas to persist (Baillie and Grabowski 2018). | ||
| Ecological Impact | Competition | |
| Field sampling shows an overwhelming dominance of Hemigrapsus sanguineus over Carcinus maenas, both in numbers and biomass at sites in Cape Cod and Massachusetts Bays (near Marshfield, Boston and Cape Ann) (Griffen and Delaney 2007; O'Connor 2013). Interference competition and aggression occur between Carcinus maenas and Hemigrapsus sanguineus. In laboratory experiments, interference between the two species 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 enclosures with H. sanguineus, C. maenas decreased its consumption of mussels, and did not switch to other foods. On a local scale, within coves at Odiorne Point, NH, a negative correlation was seen in the 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). | ||