After Rob Leewis, Arjan Gittenberger spoke at today’s marine biology day.
In a poster hanging in the lecture hall, he had written on introduced sea squirts of The Netherlands.
He wrote that over the last 50 years, six species were newcomers.
Another poster said there are now, beside the native species, three new crayfish species in fresh water in The Netherlands: Orconectes limosus and red swamp crayfish from America, and Danube crayfish from southern Europe.
In his presentation, Arjan Gittenberger dealt with many marine animals of The Netherlands.
Including the sponge Haliclona xena, a recent species for Dutch waters.
And Sagartia elegans, a rather frequent sea anemone on sandy bottoms.