Ecological effects of the invasive parasite <I>Loxothylacus panopaei</I> on the flatback mud crab <I>Eurypanopeus depressus</I> with implications for estuarine communities

Abstract

The rhizocephalan barnacle Loxothylacus panopaei (Gissler, 1884) is a parasitic castrator that infects xanthid crabs and is invasive on the Us Atlantic coast. It was introduced with infected crabs to chesapeake bay in the mid-1960s, and has since expanded north to Long Island sound, New York, and south to cape canaveral, Florida. results of an 8-mo field study (January-August 2012) indicate mean monthly L. panopaei prevalence of 18.2% ± 6.2 (mean ± 95% cI; n = 66/384; monthly range 9.4%-30.3%) in Eurypanopeus depressus (smith, 1869) in clambank creek, North Inlet, south carolina. Prey consumption was compared between parasitized (externa-bearing) and unparasitized (externa-lacking) E. depressus 8-13 mm carapace width. Parasitized crabs (n = 43) consumed significantly fewer (median = 2) mussels (5-9 mm shell height) than unparasitized crabs (n = 29, median = 4) over 72 hrs, suggesting the ecological role of E. depressus may be modified. The parasite was only found in E. depressus 5.8-14.0 mm carapace width. Unparasitized E. depressus ranged from 2.3 to 17.0 mm carapace width.