Use constraints: Data can be used freely given that the source is cited (following creative commons license CC-BY). The source should be cited as: “HELCOM HOLAS 3 Dataset (2023)"

The national survey data is compiled annually by the HELCOM Seal Expert Group. A regional database was developed within BALSAM project and has been hosted by the HELCOM Secretariat since 2015. This database will be further developed to also enable evaluation of the Distribution of Baltic seals indicator. This new database will be harmonized with the OSPAR reporting format as a part of tasks given in the Baltic BOOST WP 1.2 by the end of 2016.

The data collected and used in the indicator are based on national aerial surveys. The survey methodology is described in Galatius et al. (2014). This data covers only haul-out sites and not areas used e.g. as hunting grounds.

This core indicator evaluates whether good status is achieved by determining the growth rate of the population as well as the population size over a specified time period. The data collected and used in this indicator are based on national aerial surveys described in Galatius et al. (2014).

Each assessment unit is evaluated against two threshold value, the threshold value for population growth rate and the Limit Reference Level (LRL). The status of seals in each management unit only achieve good status if both threshold values are met.

Time series of data for each seal species and each management unit are used as input values in Bayesian analyses with uninformative priors, where it is evaluated whether observed data support the set threshold value.

Additional information:

http://www.helcom.fi/baltic-sea-trends/indicators/population-trends-and-abundance-of-seals/

Link to metadata of dataset used for indicator calculation: https://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/660bb100-790d-4f0a-bcbe-956c89811bcb