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Maritime Forum

Study 2007-07 lot 1 Web services for support of Growth an Reproduction Studies (WebGR)

Reading otoliths can be rather difficult. In order to have different scientists obtain the same results age reading needs to be calibrated. This study is setting up a website to make data available and to allow for training and calibration.

Why this study?

The systematic collection of reliable basic data on fisheries is a cornerstone to fish stock assessment and scientific advice and hence for implementing the Common Fisheries Policy. The Commission set up a Community framework for the collection and management of such data. Among the information collected by each member state are growth and maturity data that allow the building of e.g. catch at age matrices and maturity ogives. In order to get consistency regular calibration exercises must be carried out and reference material has been developed. In order to better organise this web services need to be developed.


The objective of this study is to develop a set of web services to support the organization and data analysis of calibration workshops, both for age and maturity information. The website should consist of a repository of images grouped or classified by workshop (species, date, area, etc) and accessible to all workshop participants.


  1. Develop web services for image storing, meta information storing features, like individual length and weight, sampling date and place, image annotation procedures by several scientists at the same time as; random selection of images for exercise or other relevant methods; database to store all information and allow analysis.
  2. Develop training procedures for calibration and allow for access to previous workshop results and access the expert's annotations.
  3. Implement statistical methods on line to compute bias, relative bias, variance, coefficient of variation and percentage agreement between (i) different readings of the same scientists and (ii) between readings of different scientists. These analysis must be carried out for each exercise by species and reported in Open Source formats to allow its inclusion in documents and presentations. Implement most common reports.


WebGR is constituted by a database and a web application to access the database. The database has been developed in order to contain and administer images and information on growth and reproduction structures (otoliths and gonads) to support international exchanges and workshops conducted on age and maturity determination.

The most common exercises carried out during the aforementioned workshops are counting growth rings in otoliths, or classifying gonads. WebGR provides a web application that makes such tasks easy and fast. Practically, once a Workshop has been defined, individual scientists upload images and the relevant information about the individual. Images in the WebGR repository are grouped or classified by workshop (species, date, area, etc.) and the images selected for inclusion in a workshop are accessible to all the participants, within the calibration exercises set for that workshop. Several scientists annotate each image. The annotations include fields for the classification (age x or maturity stage y, etc.), observations, scientist identity, etc. This information is stored in a database so that the statistical analysis of the results can be performed and/or the results exported.

WebGR can be used as a tool for training purposes, such as browsing images, reading experts' annotations and simulating a calibration exercise. Through WebGR inexperienced marine biologists can read otoliths or gonads and compare their results with the experts'.

WebGR can be used to manage collections of images and can become an important repository of processed biological structures with clear advantages for the scientific community.

The use of Open Source software will allow the scientific community to get involved in further developments and makes all images and annotations public. There is considerable potential for alternative applications, i.e. other processes where data are derived from human observations, such fish egg or larvae identification and underwater TV shellfish surveys.

WebGR is potentially part of a solution to the persistent problem of uncertainty in biological data.


Full title: Web Services for Support of Growth an Reproduction Studies (WebGR)

Organisations: A Consortium of European Institutions: Laboratorio Nacional de Recursos Biologicos – IPIMAR (Portugal), The Agri- Food & Biosciences Institute (UK), AZTI Foundation (Spain), Federal Agency for Agriculture and Food (Germany), Johann Heinrich von Thunen Institute (Germany), Hellenic Centre for Marine Research (Greece), Instituto Espanol de Oceanografia (Spain), Institut francais de recherche pour l'exploitation de la mer (France), Wageningen IMARES (The Netherlands), Institute of Marine Research (Norway), Institute of Marine Research (Sweden) and Italian Society for Marine Biology (Italy).

Full report: