摘要：Blooms of Mnemiopsis leidyi observed along the coast of The Netherlands in late 2006 have made the spreading of this invasive ctenophore to neighboring waters a topic of major concern. Here we report on recent occurrences of M. leidyi in Danish waters, observed partly by ourselves and other biologists, partly by beach guests, boat owners and amateur divers. The earliest record of M. leidyi is from August 2005 and the early summer of 2006, and in 2007, the earliest records are from February and March, from the northern Little Belt and Kerteminde Bay. In the period April to June, the density of M. leidyi remained very low in the Great Belt, but numerous reports indicate that the ctenophore in July to September was widely distributed in all inner Danish waters, and "mass occurrences" have been reported from certain areas.
