Who’s lurking in your lagoon? First occurrence of the invasive hydrozoan moerisia sp. (cnidaria: Hydrozoa) in new jersey, usa

Coastal estuaries represent areas of high biological invasions by virtue of their economic importance as ports. We report on the first occurrence of the non-native hydrozoan Moerisia sp. in coastal New Jersey, USA. Through the use of artificial settling plates, several diminutive, unknown cnidarian polyps were isolated. Initial morphological assessment indicated that two of the unknown polyps were keyed to Moerisia. We then used universal cnidarian primers to amplify and sequence the 16S rDNA mitochondrial locus for molecular identification. Upon evaluation and editing of sequences, two of the unknown polyps were identified as belonging to a group of unresolved Moerisia sp. taxa (> 99% homology). Additionally, polyps of Chrysaora and Aequorea were also identified from settling plates. The presence of Moerisia sp. in Barnegat Bay is the second recent documentation of an invasive hydrozoan in New Jersey and suggests that there may be other undescribed hydrozoans in this region that have yet to be been recognized, especially those with cryptic benthic life history phases.