Summary Report of aWorkshop on Geolocation Methods for Marine Animals

Abstract

The Scientific Committee on Ocean Research Panel on New Technologies for Observing Marine Life convened a workshop on geolocation methods in association with the Second International Symposium on Tagging and Tracking Marine Fish with Electronic Devices. This followed a previous workshop held in conjunction with the first symposium in Honolulu in 2000, which discussed the principles and some of the problems of estimating geolocation from underwater light measurements. The objectives of the 2007 workshop were to review advances made over the past decade in two key areas: estimation of position (using both light-based and other environmental based methods) and management and interpretation of position estimate data. The workshop also aimed to identify some of the key factors affecting the accuracy and precision of existing geolocation methods in estimating position. Consideration of the implications of uncertainties in track reconstruction for deductions about the behaviour and spatial dynamics of tagged animals was also included. This paper provides a summary of current research and technologies and the limitations of principal methods identified during the workshop. Recommendations for future development of methodology and technology included proposing a working group to better co-ordinate and consider analytical techniques and software needs. The workshop also recommended more dialogue between tag manufacturers and tag users to discuss technical issues, including sensor performance, availability of extra sensors, flexibility of tag programming, improved algorithms for light attenuation, and the compression and processing of data by tags prior to storage or transmission to satellite. Other recommendations included provision of an error field around each tag position determined by Service Argos, improved tools for visualisation of three-dimensional data and collection of an 'ideal' data set to be used for testing, comparing and developing geolocation techniques. In this context, the generation of an ideal dataset and the testing of techniques, better co-ordination and facilitation of data sharing and standardisation of quality control inputs were recommended.