Population trends and abundance of seals - Harbour seal 2018 (HOLAS 2)
Short description
This core indicator evaluates the status of the marine environment based on population trends and abundance of the three species of seals that occur in the Baltic Sea. This dataset is for Harbour seal. Good status is achieved for each species when the abundance of seals in each management unit is at least 10,000 individuals and the species-specific growth rate is achieved. Harbour seals in the southwestern Baltic and the Kattegat form a metapopulation, where subpopulations are genetically connected. The combined sizes of the subpopulations are here used to evaluate the Limit Reference level (LRL). The status evaluation is presented separately for the three seal species. The grey seal in the Baltic proper is evaluated as a single unit, whereas the Kattegat grey seals are evaluated separately. The status of ringed seals is evaluated for two management units. The status of harbour seals is evaluated for three management units. Harbour seal dataset displays the result of the indicator in HELCOM Assessment Scale 2 (Division of the Baltic Sea into 17 sub-basins). Attribute information: "HELCOM_ID" = HELCOM ID of the scale 2 assessment unit "level_2" = Name of the HELCOM scale 2 assessment unit "Assessment" = Name of assessment unity area considered "Area (km2)" = Area of the HELCOM scale 2 assessment unit "Status" = Status of the indicator (“Achieve”, “Fail” or “Not assessed”) "AULEVEL" = Assessment unit level used for the indicator "Indicator unit" = Unit of indicator (Abundance - Ringed seal / % decrease) "Threshold value" = Threshold value of the indicator "Notes" = Additional information "ConfA" = Confidence of classification "ConfT" = Temporal confidence of classification "ConfS" = Spatial confidence of classification "ConfM" = Methodological confidence of classification
Point of contact
HELCOM Secretariat
data@helcom.fi
Spatial extent
['7.526438', '33.796674', '52.535858', '66.424283']
Type
dataset
Metadata information
Identifier
Keywords
Habitats and biotopes ; GEMET - INSPIRE themes, version 1.0 ;

population trend ; marine mammal ; ecological abundance ; GEMET ;

MADS ; HOLAS2 2018 Core indicator ; Core indicator ;

Resource provider(s)
HELCOM Secretariat
data@helcom.fi

Lineage
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: http://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/e04cc4c2-35d8-45a7-abcb-dcb9501d1a15