First record of the copepod <i>Eurytemora herdmani</i> in the Firth of Forth, Scotland

The copepod Eurytemora herdmani, native to coastal waters of the north-west Atlantic and north Pacific Oceans, was discovered at a marine sampling station in the Firth of Forth, Scotland, UK. The species was present in the summer zooplankton assemblage over three successive years. Peak abundance followed peak chlorophyll a concentration in surface waters. Given that previous studies on the Firth of Forth had only found species native to Europe, a survey of the Forth estuary was undertaken in summer 2014. Eurytemora herdmani was found at sampling stations where the salinity was greater than 20, while Eurytemora affinis was found at sampling stations with lower salinity further upstream. The impact of this introduction on the native zooplankton community is not known, and will require further study. The Firth of Forth has a high level of shipping traffic, and this species may have been introduced by ships’ ballast water.