1. Introduction
Sturgeon fish are commercially cultured for caviar production, as a
result of the sharp decrease in fisheries of this group of fishes. Sturgeons
are a group of slow-growing fish that mature very late in life, and consequently,
they are particularly vulnerable to overfishing and to other
threats, like the loss of their natural habitat, river damming, and deterioration
of water quality (May et al., 1997). As a consequence, wild
stocks of sturgeons have been decreasing dramatically during these
last decades (Billard and Lecointre, 2001) and sturgeons are considered
one of the most threatened groups of animals on the IUCN Red List of
Threatened Species