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Issue Aquat. Living Resour.
Volume 22, Number 2, April-June 2009
Fish Stock Assessments Using Surveys and Indicators
Page(s) 155 - 164
DOI 10.1051/alr/2009017
Published online 17 June 2009

Aquat. Living Resour. 22 (2009) 155-164
DOI: 10.1051/alr/2009017

Notes on survey-based spatial indicators for monitoring fish populations

Mathieu Woillez1, Jacques Rivoirard2 and Pierre Petitgas1

1  IFREMER, Département EMH, BP 21105, 44311 Nantes Cedex 03, France
2  Mines-ParisTech, Centre de Géosciences/Géostatistique, 35 rue St Honoré, 77300 Fontainebleau, France

Received 30 June 2008; Accepted 23 January 2009; Published online 17 June 2009.

Abstract - This paper presents the spatial indicators used in the European project FISBOAT. These are statistics intended to capture spatial patterns of fish populations, using fish density data collected during scientific surveys. To handle diffuse population limits, indicators are designed not to depend on arbitrary delineation of the domain. They characterize the location (centre of gravity and spatial patches), occupation of space (inertia, isotropy, positive area, spreading area and equivalent area) and microstructure. Collocation between different populations is summarized by a global index of collocation. These spatial indicators have the potential to be used in a monitoring system to detect changes in spatial distribution. They could be helpful for relating the spatial distribution properties of fish stocks to their dynamics, their habitats, or to climate change.


Key words: Spatial indicators / Monitoring / Spatial patterns / Fish populations

Corresponding author: mathieu.woillez@ifremer.fr

© EDP Sciences, IFREMER, IRD 2009


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