Benthic hydroids are a common and widespread group of cnidarians. However, they are often neglected in biodiversity studies despite their high economic and ecological importance in marine environments.

Benthic hydroids constitute the bulk of the hydrozoans recorded in Norway: over 90% of the Norwegian species have a benthic stage in their life cycle, and almost 60% of all known hydrozoans in Norway are exclusively benthic. However, their taxonomy, biogeography and diversity is currently less resolved than that of the pelagic hydrozoans (i.e. hydromedusae and siphonophores) and recent findings suggest that their diversity is underestimated even in relatively well-sampled areas such as the North Atlantic Ocean.

Project NORHYDRO will map the currently insufficiently understood diversity of benthic hydroids in Norway and facilitate their identification by both scientists and non-specialists. The project will rely on existing material as well as fresh samples from several environments along the Norwegian coast, using an integrative approach that combines DNA-barcoding and careful morphological examination of live and preserved specimens. It will produce an up-to-date list of the species found in Norway, creating a solid basis for future research on hydrozoans.

Based on the observed patterns of species richness in recently analyzed hydrozoan genera from other temperate and polar regions, NORHYDRO is expected to produce the description of new species and an even larger number of new records for Norway. The project will establish a collaborative network including Norwegian and international partners, building up taxonomic competence on hydrozoans.