Invasion
Invasion Description
1st Record: Gloucester Point/VA/York River (1964, Van Engel et al. 1966, on Eurypanopeus depressus). This parasite was initially found on Eurypanopeus depressus (E. d.) and Rhithropanopeus harrisi (R. h.) in the Bay (Daugherty 1969), and later on a small percentage of Dyspanopeus sayi (D. s.) (Hines et al. 1997).
Geographic Extent
Cold Spring Harbor/NY/Cold Spring Harbor, Long Island Sound (2014, Kroft and Blakeslee 2016); Glen Cove and Sea Cliff/NY/Hempstead Harbor, Long Island Sound (8/2023, Freeman et al. 2013, on E. d.); Virginia Beach/VA/Lynnhaven Bay (Daugherty 1969); Norfolk/VA/Elizabeth River (1966, Daugherty 1969); Hampton/VA/Hampton Roads (1966, Daugherty 1969; 1983, Hines et al. 1997; E. d.); Jamestown Island/VA/James River (1966, Daugherty 1969, E. d., R. h.); Cape Charles City/VA/Old Plantation Creek (1966, Daugherty 1969); Gloucester Point/VA/York River (1964, Van Engel et al. 1966, E. d.; Daugherty 1969, E. d.; Hines et al. 1997, E. d., D. s.); Naylors Point/VA/Rappahannock River (Daugherty 1969, E. d., R. h.); Lookout Point/MD/Potomac River (1966, Daugherty 1969, E. d.); Deal Island/MD/Tangier Sound (Daugherty 1969, E. d., R. h.); Janes Island, Crisfield/MD/Chesapeake Bay (1983, E. d., D. s.); Edgewater/MD/Rhode River (1986-1993, Hines et al. 1997, R. h. only, not seen in recent years, Hines, personal communication); Quinby/VA/Hog Island Bay (1986, E. d. only Hines et al. 1997); Chincoteague/VA/Chincoteague Bay (1986, E. d. only, Hines et al. 1997)
Vectors
| Level | Vector |
|---|---|
| Probable | Oyster Accidental |
Regional Impacts
| Ecological Impact | Parasitism | |
| Loxothylacus panopaei is an abundant parasite of three species of panopeid crabs in Chesapeake Bay, Dyspanopeus sayi (Say's Mud Crab), Eurypanopeus depressus (Flatback Mud Crab), and Rhithropanopeus harrisii (Harris mud crab). As of 1983-86, its prevalence was greater on the last two species (Hines et al. 1997). Parasitism- The effects of L. panopaei on individual crabs are complex and diverse. The major impact is that both male and female infected crabs are castrated and unable to reproduce (Gissler 1884; Barnes 1983; Gould 1996), so that all of the host's feeding activity serves to support reproduction of the parasite. In order to maintain itself on a crab, L. panopaei extensively modifies the host's physiology and behavior. Details of the mechanisms are given in the "General Impacts" summary for this species. Quantitative effects of the L. panopaei invasion on densities of panopeid crabs in Chesapeake Bay have not been demonstrated. The qualitative nature of earlier studies (e.g. Ryan 1956) and the highly aggregated nature of panopeid populations (Grosholz and Ruiz 1995) make it difficult to assess the effects of this parasite. Daugherty (1969) cited personal observations of J. D. Andrews and W. A. Van Engel suggesting that since the invasion, the relative abundance of Eurypanopeus depressus had decreased compared to the then unparasitized Dyspanopeus sayi. | ||