Crabs, crayfish and lobster – Matz has written a complete guide to Crustaceans in Swedish waters
It has taken Matz Berggren nearly 20 years and he has used knowledge from his entire research career. But now, the section about Crustaceans in The Encyclopedia of the Swedish Flora and Fauna is finally complete.
"Even though these are species of great commercial interest, we still know very little about these animals," says Matz Berggren, Department of Marine Sciences, and sole author of the work.
Hermit crabs, shrimp, crabs, lobsters and crayfish – these are some of the species that belong to the group of decapod crustaceans. Matz Berggren, senior researcher at the Department of Marine Sciences and active at the Kristineberg Centre, has devoted virtually his entire research career to the small animals.
"It is an interesting group with enormous variation. There are shrimp that live in shoals and others that swim alone, fast crabs and others that are slow and camouflage themselves in different ways. Another example is the edible crab, which can migrate up to 40 kilometres to release its larvae in the right environment. They have an enormous ability to adapt," says Matz.
A lot of work behind the book
Decapods have ten legs, two of which are claws. They are mainly a marine group, but evolution has also adapted them to freshwater. In recent years, several invasive species have appeared in Sweden, such as the Asian shore crab and the Harris mud crab. During the work on the book, the Bristly crab was also found for the first time in Swedish waters, along with several other rare species. They are now all described in the new section of the The Encyclopedia of the Swedish Flora and Fauna "Crustaceans: krill-ten-legged crustaceans’".
"It's nice to see the actual result of all the work and get some closure," says Matz Berggren, who recently received a copy of the work.
Back in 2005, Matz Berggren was asked to contribute to the The Encyclopedia of the Swedish Flora and Fauna with a section on decapod crustaceans and krill. Then the money ran out and the project was put on hold, but in 2017 it was taken up again.
"I've been working very intensively on this for the past two years. We've had meetings at least once a week to check the text, systematics, images and photos, and discuss what to do next. It's been a lot of work, but very enjoyable.
Covers all known species in Sweden
No fewer than 96 species, 91 of which are decapod crustaceans and the rest krill, are described in systematic order, with text and images, in the book's more than 300 pages. All of them are found within Sweden's borders and can be spotted with the naked eye, says Matz Berggren, who is the sole author of all the text in the book and also took several of the pictures. Linda Nyman, who has worked on several parts of the The Encyclopedia of the Swedish Flora and Fauna, has illustrated the book, and Fredrik Pleijel, marine biologist and photographer, has contributed pictures.
"In terms of knowledge, we are now at the forefront. The information in the book is current as of today," says Matz Berggren.
He hopes that the work will be useful both for the interested general public and for schools and universities, but also for others who work with species identification.
"In today's situation, we have many new species coming in that are important to keep track of. I think the book can be a great help in the work of identification," says Matz Berggren.
The Encyclopedia of the Swedish Flora and Fauna aims to make knowledge about Sweden's species and their habitats available to the public, with the goal of increasing engagement in biodiversity.
The Swedish University of Agricultural Sciences estimates that there are up to 60,000 species in the country. The project started in 2005. It is the only book series of its kind in the world and represents a knowledge boost for Swedish nature conservation.
On 28 August 2025, the 22nd volume in the series will be published, "Crustaceans: Krill-ten-legged crustaceans’", written by Matz Berggren, senior researcher at the Department of Marine Sciences.
Over 3,000 previously unknown species have been discovered in Sweden through the project, of which at least 1,000 were completely new to science – strengthening research and nature conservation.
Read more about the Encyclopedia of the Swedish Flora and Fauna here (Swedish)