2024 Red List II of Marine Mammals
Five marine mammal species are residents in the Baltic Sea: the grey seal, harbour seal, ringed seal, harbour porpoise and Eurasian otter. Of the seals, the grey seal lives in the whole region and the harbour seal only in the southwestern Baltic Sea and the Kattegat. The ringed seal is restricted to the eastern and northern Baltic Sea. The harbour porpoise is found throughout the Kattegat, the Belt Sea, the Sound, the southern parts of the Baltic Sea and the Baltic Proper. The Eurasian otter can be found in the whole Baltic Sea region mainly along the coast.
Overview of the assessment results for mammals
From the five marine mammal species that were evaluated two species (with their respective subpopulations) were categorized as threatened (CR-VU) in the HELCOM Red List II assessment:
- Phocoena phocoena (Baltic Proper) kept as Critically Endangered
- Phocoena phocoena (Belt Sea) Endangered (previously Vulnerable)
- Pusa hispida botnica (Southern Management Units) Endangered (previously Vulnerable)
- Pusa hispida botnica (Gulf of Bothnia) kept as Vulnerable
The total list of the assessed marine mammal species and the categories assigned to them are available in Annex 5 of the Red List II species report.
Red List categories within the assessed mammal species
Out of the total list of 5 mammal species of the HELCOM Checklist 2.0 (HELCOM 2020), all five species entered the Red List II assessment process, all of which had also been assessed in 2013. Ringed seals were assessed as a single assessment unit in 2013 Red List thus seven assessment results compared to the eight assessment results in 2024 Red List II.
In 2024, three species were categorized as Least Concern, compared to two species in 2013. Both in 2013 and in 2024 one species were categorized as Near Threatened. Phocoena Phocoena (Belt Sea) and Pusa hispida botnica (Southern Management Units) were categorized as Endangered in 2024, none in 2013. Pusa hispida botnica (Gulf of Bothnia) was Vulnerable in 2024, compared to the three species (Phocoena phocoena (Belt Sea), Pusa hispida botnica and Phoca vitulina (Kalmarsund)) in 2013. Phocoena phocoena (Baltic Proper) kept its Critically Endangered category both in 2013 and 2024.
Ringed seals were assessed as a single assessment unit in 2013 Red List but was divided for the 2024 assessment into two subpopulations: the Southern Management Units and the Gulf of Bothnia subpopulations.
Red List categories and Species Information Sheets (SIS)
The Species Information Sheets (SIS) were updated for those species that were categorized as threatened during the Red List II project, meaning those assessed as Critically Endangered, Endangered, Vulnerable and those categorised as Regionally Extinct. For those species that were categorized as threatened for the first time, a SIS was produced with only a summary table and distribution map.
| Red List II / SIS 2024 | Criteria 2024 | Scientific name | Common name | Red List / SIS 2013 | Criteria 2013 |
|---|---|---|---|---|---|
 | C2a(ii) | Phocoena phocoena (Baltic Proper) | Harbour porpoise | | C1,2a(ii) |
 | A2ad | Phocoena phocoena (Belt Sea) | Harbour porpoise |  | A2a |
| C1 | Pusa hispida botnica (Southern Management Units) | Ringed Seal | | A3c |
| A3c | Pusa hispida botnica (Gulf of Bothnia) | Ringed Seal | | A3c |
 | D1 | Phoca vitulina (Kalmarsund) | Harbour Seal | | D1 |
 | Halichoerus grypus | Grey Seal | | ||
| Phoca vitulina (Kattegat/Southwestern Baltic) | Harbour Seal | | ||
| Lutra lutra | Otter | | D1 |