Ronan Fablet, Jean-François Bardeau, Abdesslam Benzinou,
Anatole Chessel, Aurélie Jolivet, Maylis Labonne, Anne Lorrain,
Yves-Marie Paulet, Vincent Rodin and Hélène de Pontual.
Understanding otolith biomineralization: from physico-chemical signatures
to numerical modelling.
Symposium Ecosystem Approach to Fisheries, pages 9-11,
Boulogne-sur-Mer (France), 5-7 November 2008.
Abstract:
Fish otoliths, calcified structures located in the inner ear, are
actual biological and environmental archives. Their accretionary
growth results from a strict physiological control of the organism,
but is influenced by the environmental conditions in which the fish
lives. For instance, environmental variables such as temperature and
salinity, as well as season-based or age-based metabolic variations
are known to influence the deposit rate and the incorporation of
chemical elements. This accretionary process often leads to the
formation of sequence of structures (rings), whose periodicity goes
from the day to the season. Otolith analysis then offers a unique
potential to reconstruct, at a daily and/or yearly scale,
environmental parameters as well as individual life traits (age,
growth patterns, migration patterns,...), and provides the mean to
acquire information at different biological level: the individual
level, in terms of individual life traits, the population level
regarding age-based population statistics or spation-temporal
population structures, the environmental level in terms of
reconstruction of temporal series of environmental parameters.
Over than a million of otolihs are thus analyzed yearly worldwide
for fish stock assessment as well as ecological studies.
Although otolith analysis is now recognized as an invaluable source
of information, the decoding of the metabolic and environmental
information archived by the otolith remains critical and new tools
are needed to achieve a robust calibration of the archive. The last
decade has mainly focused on the detection of significant
statistical links between environmental and/or metabolic conditions
and otolith signatures. Such an empirical framework actually led to
significant scientific advances (eg., the calibration of
δ18O
signal as a proxy of temperature). However, in many situations, the
otolith signal remained non-interpreted. These difficulties stress
the needs for characterizing and understanding the biological
basis of biomineralization processes.
Within the framework of the project ANR JC OTOCAL, these issues
have been addressed from a multidisciplinary point of view in
order to characterize and to model the processes involved in the
otolith formation, and their modulation by environmental factors
and the physiology of the organism. Two major topics have been
jointly investigated: enriching the multivariate structural and
chemical characterization of fish otoliths, modelling otolith
formation.
Keywords:
Fish otoliths, Biomineralization, Otolith imaging, Otolith chemistry,
Bio-energetic model.
[Fablet08a.pdf]