The Baltic Sea is a semi-enclosed sea with nine states bordering the sea. It consists of eight sub-catchment areas (sub-basins) and numerous harbours. It is estimated that about 2000 sizeable ships are at sea at any time, making the number of ships one of the highest in Europe. These ships will undoubtedly generate underwater noise that potentially might be harmful for the Environment. The BIAS project was established in September 2012 to support a regional assessment of the underwater sound in the Baltic Sea. The project has five objectives. The first is to raise awareness among authorities and managers. The second is to establish a regional implementation. The third objective is to assess the level of underwater noise and to present the results as soundscape maps. The fourth objective is to establish regional standards and methodologies that will allow for cross-border handling of data and results and finally to  implement regional tools for handling of underwater sound.


BIAS end-of-project workshop completed

The end-of-project workshop of the BIAS project has come to an end. During two intensive days, 1-2 June 2016, managers, regulators, scientists and policy makers have been informed on the results of the project at the Swedish Agency for Marine and Water Management, SwAM, in Gothenburg, Sweden.

All presentations during the workshop are now available on the webpage. Follow the link to get to the BIAS end-of-project workshop page, where you will find the presentations.


Participants in the BIAS end-of-project workshop.

BIAS End-of-Project Workshop

BIAS End-or-project workshop will soon take place! More information is available on the BIAS end-of-project workshop page.

See the updated agenda for the workshop


BIAS scripts

The BIAS matlab scripts are now available on the webpage. Visit the page to download the scripts!

Updated BIAS standards for noise measurements

Earlier in the BIAS project, a standard for noise measurements dealing with standards of data handling, standards of handling of sensors, standards of rigs and standards of sensors was developed in order to make the field measurements comparable. The BIAS standard for noise measurements was adopted by the Technical Group Noise (TG Noise) that supports Member states on advice on the MSFD. A lot of lessons learned were done throughout the project after the first version of the standard. This has now been added to the conclusive version of the standard.

Bias standards for noise measurements is now uploaded on the webpage!


BIAS standards for signal processing

The conclusive version of the BIAS standards for signal processing is now available!

The signal processing within the BIAS project is restricted to topics related to the analysis of the retrieved digitized sound data. The main parts are to control the quality of data, to extract relevant estimates out of the raw data set, to present the properties of data in an understandable way and to provide results in an appropriate format for sound scape modelling. Pre-processing is a basic step in signal processing to prepare data for data analysis and to assess the quality of the data.

For the quality control of data BIAS use defined pre-processing procedures such as: testing of self-noise, organisation of recorded data, testing of data coverage, testing of file size and file length of the recorded files, testing of non-numerical values in the recorded data files and testing of clipping of the data.

Signal processing of data constitutes the main analysis of the raw data with the aim of extracting the fundamental measures needed for modelling sound propagation and to sum up the statistics. Processing of the sound data includes both filtering of data and data analysis. In the first step, an FFT-analysis is done over consecutive 1-second periods, giving amplitude spectra with a 1 Hz resolution. In the second step, the sound pressure levels (SPL) are calculated in the required 1/3-octave bands over 1 second. The 1-s averages are then further processed to averages of 20 seconds.

Similarly, estimates such as hourly, daily and monthly averages are also calculated based on the 1-s averages. Finally, the annual mean is derived using the 1-s averages. In BIAS monthly and annual arithmetic means and the percentile levels are established for 63, 125 and 2000 Hz as well as for the frequency band from 10 to 10,000 Hz.



BIAS in Paris: Towards a convergence?

The BIAS project started 2012 and is coming to an end in 2016. A number of milestones have been completed in the project. This presentation gives a short summary of what has been achieved. At the end of the presentation is both GES and DPSIR discussed as well as a short glimpse given on the GIS-based planning tool.

BIAS Summary 2016

BIAS presentation Paris


The QA report

The aim of developing and applying Quality Assurance is to make the output of the Project reliable for management of underwater noise in accordance with Marine Strategy Framework Directive (MSFD) descriptor 11. Among other procedures, this is done by establishing and applying quality control tools, such as checklists or control charts. The report Full QA report with Appendixes are now down loadable from this web site. Follow this link:

QA report



The GIS-based planning tool

GIS-based planning tool

The conceptual idea on the GIS-based planning tool for handling of the soundscape is finished. AquaBiota has released the first version, which will soon be demonstrated for the first time for stakeholders. If you are interested you can find more information on the tool under this link BIAS_Soundscape_Planning_Tool_Concepts_June2015.

BIAS Newsletter

Latest edition of the BIAS Newsletter is out now!


Do you want to subscribe to the newsletter? Yes! Please sign me up for more news about BIAS.

The use of side-scan sonar for localizing and inspecting rigs


The BIAS Project has investigate the use of side-scan sonar in inspecting and finding rigs. The study was performed in Polish water where trawling is frequently occurring. One of the rigs where lost. It was localized by using side-scan sonar. The rig was later retrieved by divers using the location obtained from the side-scan sonar. The conclusion is that side-scan sonar is an effective mean to find lost rigs, especially when trawls have moved the rig a fair distance from the deployment position.

First page

Side-scan sonar survey carried out


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