This pre-core indicator and its threshold values are yet to be commonly agreed in HELCOM. The indictor is included as a test indicator for the purposes of the 'State of the Baltic Sea' report, and the results are to be considered as intermediate.
The data and resulting data products (tables, figures and maps) available on the indicator web page can be used freely given that the source is cited. The indicator should be cited as following:
HELCOM (2018) Number of drowned mammals and waterbirds in fishing gear. HELCOM core indicator report. Online. [Date Viewed], [Web link].
There is currently no source of monitoring data which specifically compiles and analyses the numbers of by-caught waterbirds and marine mammals in a representative manner. Some information on harbour porpoise incidental by-catch is taken from the ICES WGBYC database (as presented in the reports ICES 2015, 2016a) which is based on information in Reg. 812/2004 National Reports.
Temporal coverage of monitoring data is poor. Some studies can be used for historical sporadic information on numbers of by-caught waterbirds and mammals. These sporadic data have a very poor spatial coverage (see map in Žydelis et al. 2009).
In the BSAP, it was agreed to set up a reporting system and database for harbour porpoise incidental by-catch which have not yet been developed.