Brackish Water Hydromedusa Maeotias inexpectata in North America

TLDR: For example, during two successive cruises to the Pamunkey River in autumn 1968, hydromedusae of the family Olindiidae, never before found in Virginia, were collected in trawls.

Abstract: THE Virginia Institute of Marine Science has recently been studying the biota of waters of low salinity in several Chesapeake Bay tributaries. During two successive cruises to the Pamunkey River in autumn 1968, hydromedusae of the family Olindiidae, never before found in Virginia, were collected in trawls. The specimens were identified as Maeotias inexpectata, a brackish water species originally described from the Don and Kuban estuaries, Sea of Azov1, and known elsewhere only from the Black Sea2. Ten specimens were collected on October 15, 1968, at station P–40 (37° 33′ N, 76° 53′ W, 4.2‰ salinity, 20.1° C water temperature) and one specimen was found on November 14, 1968, at station P–30 (37° 33′ N, 76° 50′ W, 10.7‰ salinity, 11.3° C water temperature. Hydrographic conditions at these two stations vary considerably at different tidal stages as well as seasonally, but salinities are mesohaline or lower at all times. Over a 13 year period, 1955–1967, the mean salinity and temperature during autumn were 9.0‰ and 12.5° C at station P–30, 1.2‰ and 12.2° C at station P–40 (W. A. Van Engel, personal communication).