In 2009, Hans published a Dutch identification guide for marine and brackish water Bryozoans ("moss animals") of the Southern Bight of the North Sea, illustrated with drawings, scanning-electron and light microscope images. It is a reliable reference for professional bryozoologists and keen amateur naturalists studying northern European bryozoans. This virtually complete inventory of a group of animals that have been the object of very few studies so far, but that encompasses a surprisingly large variety of species. The sandy substrate that is predominant in this area is usually poor in moss animal species. The fact that such a large number of species are described in this work is the result of an in-depth study of recent observations (tidemark material, specimens collected on the hard substrate of breakwaters and port structures, shells and stones near sandbanks) and the review of historical collections.
As many as 179 species were discussed in the Dutch book; the present English update treats 201 species, describing 9 species as new to science. The area bounded to the south by Cap Gris Nez (Northern France) covers the Belgian and Dutch coast and is now extended to the German North Sea coast. This update includes more native and non-indigenous species, new distribution data, new taxonomic insights, additional references, and additional or better illustrations. What is especially remarkable is that each species has been illustrated using both a stereomicroscope showing natural coloration and colony shape, and a scanning electron microscope showing small details of zooidal morphology.
Thanks to the different identification keys in the book and a 20-30× magnifying glass, it is possible to recognize most of the moss animals in the study area. We hope that this work will contribute to a better understanding of this colony-forming, undervalued group of animals.
Chapter 1. General Introduction
Chapter 2. Cyclostomatida
Chapter 3. Ctenostomatida
Chapter 4. Cheilostomatida
Hans De Blauwe showed a broad interest in nature from a young age. Shells, amphibians and fossils in particular attracted his attention. At the age of 11, he became a member of the Belgian Youth Association for Nature Studies and became acquainted with birds. From the age of 16, he participated in an inventory of Syrphid flies. His thesis in the secondary horticultural school in Melle dealt with galls and gall-causing insects. In 1983, he graduated as a teacher (bachelor) in science and geography. His first childhood dream came true when he became a professional fireman in 1991. In the meantime, he continued to pursue his second vocation, biology, as a hobby. In 1999, his attention turned to jellyfish, which he inventoried in the Zeebrugge area, and moss animals. In 2004, Hans became a voluntary scientific employee of the Royal Belgian Institute of Natural Sciences (RBINS), after he had already eagerly accepted an invitation to revise the institute's moss animal collection and to participate in a campaign on the Hinderbanken. He discovered many introduced moss animals and other marine invertebrates in harbours and estuaries. The original plan to adapt Lacourt's identification guide for bryozoans to the current situation got out of hand. This work is the result of that. Hans has produced a vast body of literature over the last 25 years, authoring 112 papers that include the description of 26 new bryozoan species and 3 new bryozoan genera. His particular interest in identifying and reporting non-native and invasive species has been generating continuous data since 2006 through his contributions to the checklist of Non-native species in Belgian waters of the North Sea and the surrounding estuaries. In 2000, the Linnean Society of London awarded Hans the H. H. Bloomer Award for his important contribution to the knowledge of natural history as an amateur naturalist.