Position Statement 8: Marine Mammal Observer (MMO) and Passive Acoustic Monitoring (PAM) Data Collection and Analysis

Position Statement 8: Marine Mammal Observer (MMO) and Passive Acoustic Monitoring (PAM) Data Collection and Analysis

Using Suitably Qualified MMOs and Thorough Methodology

The Marine Mammal Observer Association (MMOA) maintains that to maximise the value of data collected during mitigation surveys, it is essential for MMOs and PAM Operators to be suitably qualified, experienced and dedicated. Any data that are to be scientifically analysed need to have been collected using a structured, standardised methodology and then should be fully assessed for data quality before analysis can begin. Meaningful analyses should only include data collected by people with proven species identification skills, an appreciation for the necessity for correctly recording effort status and weather conditions, and good distance estimation skills. Using inexperienced persons and individualised data collection methodologies will lessen scientific credibility.

Use of Photographs to Improve MMO Data Quality

MMO data is of superior quality if photographs of each sighting are collected and stored (bearing in mind that it is not possible to photograph every sighting because animals are often seen briefly or at distance or in inclement weather conditions). The collection of supporting images allows later independent-verification of the sightings, especially in terms of species identification. This is particularly important in areas where little information exists of marine mammal distribution. The MMOA encourages Clients to specifically request MMOs who are able to take good-quality photographs during sightings to maximise the quality of the data being collected and their subsequent use for scientific purposes.

Collating PAM Detection Recordings and Noise Samples

Retaining and collating recordings of PAM detections and samples of sound is not a widespread requirement with regulators. The MMOA encourages Clients to specifically request that recordings of every PAM detection are made and stored during a survey, so that independent verification of the data can occur at a later time and the use of the data be maximised. This process will also facilitate assessment of the signal-to-noise ratio and other recording parameters experienced during PAM surveys with a view to assessing the likely potential for detections to have occurred on the system.

MMO and PAM Data Analysis

Analysis of the data collected during mitigation surveys should be carried out by individuals/organisations that have a full understanding of the limitations of current MMO and PAM datasets. Datasets collected by multiple personnel of varying skill levels are inherently subject to wide variation in standards. Although this variation can be minimised to some extent through the use of standardised data collection methods and data forms, bias in detection rates and identification skills between observers is an acknowledged and fundamental issue for all large marine mammal surveys, and will be especially the case in large MMO/PAM datasets where data may originate from several hundred observers. Meaningful analyses are reliant on having an understanding of the varying quality of MMOs and PAM Operators being hired on projects and the limitations this creates (for example, the ability to account for inter-observer variation during analysis). An assessment of which data are of scientific value can only be achieved if the data are accompanied by detailed descriptions of the methodology used, by supporting information allowing independent verification (i.e. photographs or acoustic recordings) and an indication of whether the data were collected by dedicated, experienced and qualified MMOs and PAM Operators.

Collating MMO and PAM Datasets Worldwide

The MMOA supports the standardisation of data collection methods and the data forms used to record data worldwide, in order to improve the value of global datasets. MMO and PAM data forms in an electronic version have been developed by the E&P Sound and Marine Life Joint Industry Programme (JIP) (www.soundandmarinelife.org), a body affiliated with the International Association of Oil and Gas Producers (IOGP). The data forms have been frequently revised following extensive feedback from MMOs and PAM Operators working in the field. The MMOA encourages the adoption of these forms with their guidance notes, where appropriate, to improve the standardisation of MMO data worldwide. These forms have been adopted by, amongst others, the Joint Nature Conservation Committee in the United Kingdom and can be found online at: http://jncc.defra.gov.uk/page-1534.


In summary to maximise the value of MMO data for scientific purposes the data must be:

  • Collected by suitably qualified and experienced MMOs and PAM Operators.

  • Collected using a standardised methodology (e.g. through the use of JIP-funded MMO data forms).

  • Quality-controlled by assessing the experience of the MMO or PAM Operator and by validating data (i.e. through the use of photographs and acoustic recordings).

  • Accompanied by photographs and acoustic recordings whenever possible for each visual or acoustic detection.

  • Analysed by individuals/organisations that have a full understanding of how MMO and PAM data are collected, have been collected in the past and what the limitations are.

The potential uses of MMO data for scientific research purposes have resulted in some MMOs seeking permission from the Client to publish their own data from work on seismic survey vessels. The MMOA encourages this practice. Please refer to Position Statement 9 - The Use of Marine Mammal Observer (MMO) data for Scientific Publications – for further information.


This is one of ten position statements produced by the MMOA. All of the MMOA Position Statements are available for download in a single document in addition to viewing on this website. To download this document please click here

About the Marine Mammal Observer Association (MMOA)

mmoa footer logoThe Marine Mammal Observer Association (MMOA) is a membership based association with the aim of bringing together and representing individuals who work commercially and professionally as Marine Mammal Observers (MMOs) and Passive Acoustic Monitoring (PAM) Operators who implement mitigation measures to protect marine life during industry operations. The MMOA also provides information to other individuals that have an interest in MMO issues.