Verslag excursieweekend Noordoost-Groningen, 29 en 30 juni 2019

On June 29 and 30, 2019, a mollusk inventory was carried out at various locations in the northeastern part of the province of Groningen, with an emphasis on mollusks that prefer brackish conditions. In the saltmarshes outside the dike, living specimens of Dwarf surf clam Mulinia lateralis, Dun sentinel Assiminea grayana and the saltmarsh slugs Alderia modesta and Limapontia depressa were found. Inland brackish waters yielded Conrad’s false mussel Mytilopsis leucophaeata, Gulf wedge clam Rangia cuneata and Spire snail Ecrobia ventrosa. The discussion addresses, among others, the absence of the Lagoon cockle Cerastoderma glaucum, one of the most numerous species in the area, prior to its embankment. This species prefers shallow tidal river systems with a gradual fresh-salt water transition, an environment currently absent from the province of Groningen.