5th International Otolith Symposium

Workshop on Otolith Shape Analysis (whole day)

Workshop registration is now closed - please contact the organizing committee for details about participation

Organizing committee:
Deirdre Brophy (Chair), Alf Harbitz,
Lotte Worsøe Clausen, Antoni Lombarte,
and Audrey Geffen


One of the most rapidly developing applications for otolith techniques is shape analysis, often used for population discrimination as well as for species identification. The growth rate and shape of the otolith is thought to be regulated by the protein matrix. In this way, fish growth and protein synthesis control the rate of otolith growth. The shape of the otolith is influenced by environmental factors, but also shows consistent and temporally stable differences between populations, which suggests genetic control. Otolith shape can be characteristic of a fish population, and thus serve as a population marker, suitable for individual assignment.

Shape analysis is attractive because it appears to be relatively easy and inexpensive, and can be done using archived collections of otoliths. The technique relies on image acquisition, image analysis, extraction of shape variables, and statistical data models – and until recently there has been little attempt to compare or standardize the protocols used. To ensure that images and analyses can be shared and compared, it is advantageous to have an exchange of methods and to develop a network of researchers who can comment on developing techniques.

This workshop aims to update participants on the tools available for studying fish otolith shape, with emphasis on image acquisition and shape analysis. The WS will also provide examples of different image analysis protocols, and compare the techniques used for different species. The content is targeted both at researchers with little background in otolith shape analysis and at those with more experience of the method.  Through a combination of demonstrations and hands-on computer exercises, participants will learn how to perform otolith shape analysis (acquire images, extract outlines, obtain shape descriptors and analyse data). Workshop presentations will inform participants of the theoretical basis for the technique and its application to stock discrimination and will also cover recent advances and more specialized applications.  Practical sessions and panel discussions will provide the opportunity for comparative evaluation of various methodological approaches. Opportunities for calibration, standarisation and validation of image analysis protocols using web based resources will be explored.


09:00-9:45  Oral presentations

    • Otolith shape analysis in stock discrimination
    • Theory behind the practice of shape analysis – Biological & Mathematical

9:45-10:30 Demonstration

    • Image acquisition - code of best practice for obtaining high quality images with unambiguous outlines

Morning break

11:00-13:00 Demonstrations and interactive practical session

    • Image processing and generating automatic outlines
    • Shape data extraction (shape indices, harmonics and landmarks)

Lunch break

(with demonstrations from scientific equipment/software enterprises)

14:00-16:30 Demonstrations and interactive practical session

    • Data analysis, including important covariates and potential pitfalls

16:30-17:00 Oral presentations

    • Beyond stock ID – recent advances in otolith shape analysis and its application

17:00-18:00 Panel discussion

The planned schedule will mix theoretical and practical topics in each session, to facilitate demonstrations of the principles and maximize the time available for demonstrations.  Participants are requested to bring their own laptops to the workshop and upload the required software before the workshop (links will be provided via the conference website). Participants also are encouraged to bring data and/or images to the workshop and to present any specific queries on the analysis of otolith images or shape data to the organizing committee well in advance of the workshop. This will allow us to incorporate specific user issues into the format of the day as time allows.

Please record your interest through the Symposium web-site.

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Workshop on Otolith Shape Analysis (whole day)

International Council for the Exploration of the Sea (ICES) · Conseil International pour l'Exploration de la Mer (CIEM)
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