First European record of the invasive barnacle <i>Balanus glandula</i> Darwin, 1854

During recent surveys of hard substrata biofouling communities in Belgian marine waters we discovered specimens of the invasive barnacle Balanus glandula. This species is new to the European marine fauna. The species was first encountered in July 2015 in a biofouling community on RV Belgica. In October 2016, the species proved to be common on navigational buoys in Belgian coastal waters and after a dedicated search we discovered the species on many groynes all along the Belgian coast and in the harbour of Zeebrugge. We identified the species both morphologically and genetically. We found two generations indicating that B. glandula had settled in 2015 (possibly the first year of its presence) and also in 2016. We provide identification characters to distinguish B. glandula from other, similar looking, Western European intertidal barnacles. The distribution of B. glandula was originally limited to the Pacific coast of North America. In the past half century B. glandula successfully invaded subsequently the coasts of Argentina, Japan and South Africa. Given its invasion history elsewhere, we forecast that B. glandula is on the brink of invading other European shores

Fouling community on the foundations of wind turbines and the surrounding scour protection

The introduction of hard substrata in the mainly sandy environment of the Belgian part of the North Sea provides a new habitat to species that could previously not establish in the area. The community is dominated by the amphipod Jassa herdmani, the hydroids Tubularia larynx and T. indivisa and Actiniaria species, of which the plumose anemone Metridium senile is the most dominant. Only few species, especially those arriving early in the colonization process, are able to establish a viable population. The vertical foundations and the complex three-dimensional structure of the scour protection harbour different fouling communities

Not necessarily all gold that shines: appropriate ecological context setting needed!

At present, everybody agrees that offshore wind farms do impact the natural environment. Whether or not these impacts should be valued positive or negative, or ecologically and societally acceptable, however remains an open question. While boosting local species richness, the artificial hard substrata may for example also open the door to non-indigenous and even invasive species. Some fish and seabirds are further known to be attracted to wind farms, but fish do not necessarily take profit from these structures and seabirds may suffer from an increased collision risk. The true impact will therefore be valued only if local observations are up scaled to the ecoregion level