Sea slugs of southern Norway

Sea slugs are the popular name for a group of gastropod molluscs either lacking a shell or with a reduced and modified shell. They are best known by their bright and flamboyant colours and shapes and are a prime target for underwater photographers and scuba diving enthusiasts that often refer to them as the “butterflies of the sea”. Recently, these molluscs have received attention in Norway, but studies have only focused on the single Order Nudibranchia in the central part of the country between Sogn og Fjordande and Nord-Trøndelag. For nearly 80 years that no dedicated survey and scientific work on these animals takes place in southern Norway, a vast span of coastline between the Bergen area and the border with Sweden. This region has been identified to be the most vulnerable in the country for the arrival and establishing of alien species of temperate water affinities and is certainly most prone to share marine faunistic elements with other Scandinavian countries where many species not recorded so far in Norway have been reported.

This project aims to ascertain the diversity, distribution, and ecology of all groups of sea slugs present in Norway (Orders Anaspidea, Nudibranchia, Pleurobrancomorpha, Sacoglossa, and Umbraculida) with a focus on the southern counties and to detect the presence of alien species while in parallel will establish DNA and image libraries for all species collected.

We will study museum collections yet the emphasis is on newly collected specimens obtained by boat dredging, but mostly by snorkeling and scuba diving sampling in rocky shores and kelp forests. All species will be photographed alive for their colour patterns and external morphology and DNA barcoded. In the case of potential cryptic species-complexes additional genetic and anatomical studies using scanning electron microscopy will be performed.

The project benefits from national cooperation with the Norwegian University of Science and Technology, Trondheim, University of Agder, Kristiansand, and the Institute of Marine Research at Flødevigen and with the expertise of international researchers from the University of Gothenburg, Sweden and University of Cádiz, Spain. Besides, the project will implement and coordinate a programme of Citizen Science establishing a network of “citizen scientists” (divers and marine life enthusiasts) eager to work together with the project collaborating with data and specimens.