The use of genetic, biochemical and electronic markers in population biology
and ecology has been growing tremendously during the last two decades. The
first part of this paper aims at reviewing the main principles and advances
of these individual markers through a few key applications on exploited
marine fish populations. The second part is more prospective and
investigates some possibilities that could arise in the near future through:
(i) the development of new markers, (ii) the combination of different
markers and (iii) the combination of quantitative approaches -whether
classical or new- with individual markers. It is finally stressed how
crucial individual markers will be to unravel the biocomplexity of wild fish
populations and the key role they should play in the implementation of the
ecosystem approach to fisheries.