Monitoring programme: Biodiversity - MammalsProgramme topic: Mammals
Updated on 15 June 2016
The monitoring of this sub-programme is: partly coordinated within HELCOM SEAL
ad hoc expert group.
Common monitoring guidelines
Common quality assurance programme: missing. National QA/QC exists.
Common database: expected to be ready in late-2016.
Biological features:A description of the population dynamics, natural and actual range and status of species of marine mammals and reptiles occurring in the marine region or subregion.
Population size (abundance)
Species distributional range/pattern
1.1.1 Distributional range
1.2.1 Population abundance
1.2.1 Population abundance
4.1 Productivity (production per unit biomass) of key species or thophic groups
Detailed information on monitoring frequency and spatial resolution has not yet been collected from all countries but will be added.
Harbour seal/abundance and distribution: triple surveys carried out annually during moult in August covering the entire area of distribution.
Grey seal/abundance and distribution: coordinated surveys in end of May-early June annually.Ringed seal/abundance and distribution: annual line transect surveys in the Bothnian Bay and Archipelago Sea, sporadic in the Gulf of Finland and the Gulf of Riga. Archipelago Sea, Gulf of Finland and Estonian coastal waters only monitored under ice conditions.
Kattegat, Great Belt, The Sound, Kiel Bay, Bay of Mecklenburg, Arkona Basin, Bornholm Basin, Eastern Gotland Basin, Western Gotland Basin, Gulf of Riga, Northern Baltic Proper, Gulf of Finland, Åland Sea, Bothnian Sea, The Quark, Bothnian Bay.
For grey seals and harbour seals all significant seal haul-outs are covered.For ringed seals, at least 13% of the ice-covered sea area is monitored.
Monitoring is to be carried out to fulfill assessment requirements of HELCOM ecological objectives that are specified through HELCOM core indicators. The requirements on monitoring can
include number of stations, the sampling frequency and replication.
The grey seal range is expanding, and minor localities in Germany and Poland are not covered by the current programme. While currently insignificant in regard to the general abundance, they may grow to become significant in the future. In Denmark, the grey seals are only surveyed once during the moulting season, while each locality is surveyed twice in Sweden, Finland, Russia and Estonia. This makes the counts from Denmark less robust.
Warmer winters in recent years have resulted in reduced ice cover, making estimates in such years unreliable. This compromises the power to detect trends and calls for design of alternative methods.
With the current methodology, absolute abundances cannot be estimated for any of the species, as correction factors taking into account the proportion of the population that is hauled out during the surveys do not exist for any of the species in the Baltic. Studies to address this gap need to be performed.
Data for ringed seal southern populations is insufficient due to poor ice conditions. Alternative methods are being developed.
Adequacy for assessment of GES (Q5d)
Monitoring should provide adequate data and information to enable the periodic assessment of environmental status, and distance from and progress towards GES as required by MSFD under Article 9 and 11.
Assessment of natural variability
Quantitative and Qualitative. Population trends are achieved by the time series of seal counts. Analyses are exemplified in Teilmann et al. 2010.
Contact point to national monitoring programmes will be added
Teilmann J., Riget F., Härkönen T. 2010. Optimising survey design
in Scandinavian harbour seals: Population trend as an ecological quality
element. ICES Journal of Marine Science, 67: 952–958.
Härkönen T., Stenman O., Jüssi M., Jüssi I., Sagitov R., Verevkin M. 1998.
Population size and distribution of the Baltic ringed seal (Phoca hispida
botnica). In: Ringed Seals (Phoca hispida) in the North Atlantic. Edited by
C.Lydersen and M.P. Heide-Jørgensen. NAMMCO Scientific Publications, Vol. 1, 167-180.
Härkönen T. and Lunneryd S.G. 1992.
Estimating abundance of ringed seals in the Bothnian Bay. Ambio 21:497-510.