Population dynamics of the spiny dogfish – Sweden’s “last” coastal predator

The spiny dogfish population has recovered substantially, most likely as a result of the fishing ban. After having come close to collapse, the population has recovered sufficiently for a fishing quota to be reintroduced. However, considerable uncertainty remains in stock assessments, and our fundamental ecological knowledge of this coastal top predator is still very limited.

Swedish authorities have recently highlighted these knowledge gaps and emphasised the need for a stronger scientific basis for management. Our aim is therefore to map the movement patterns, size distribution and population dynamics of spiny dogfish along the Swedish west coast – from Bohuslän in the north to Halland and northern Skåne in the south. This will allow us to identify important habitats, such as mating and nursery areas, and determine where the species is most vulnerable to both commercial and recreational fisheries.

The project is led by Petter Lundberg (petter.lundberg@slu.se) and Daniel Palm (daniel.palm@slu.se).

August 2026 update: Successful spiny dogfish tagging along the Swedish west coast

We finally carried out our major spiny dogfish expedition along the Swedish west coast. Over two weeks, we worked our way south from Koster to Stora Middelgrund, searching for, sampling and tagging spiny dogfish.

Despite challenging weather conditions, the expedition was highly successful. In total, we sampled 116 spiny dogfish from four different areas along the coast. All individuals were fitted with conventional T-bar tags, and the majority were also equipped with acoustic transmitters. Eight larger individuals were fitted with satellite tags.

Around two-thirds of the tagged spiny dogfish were females. Using ultrasound, we were able to confirm that a large proportion of these were pregnant, providing valuable information about the occurrence and habitat use of large females in Swedish coastal waters. The sharks ranged in size from 57 to 107 cm.

Together with sampling from previous years, we are now approaching the project target of 150 sampled individuals. The next step will be to analyse the samples collected and, in spring 2027, download detection data from the network of acoustic receivers that we maintain in the Skagerrak and Kattegat. This will provide the first insights into how the tagged spiny dogfish have moved. 

The project's page on funder's website: Save our seas foundation.