Trout taxonomy: legends, assumptions, concepts and reality
Most publications on trouts include some kind of ritual statements alluding to a too great variability, that cannot be handled by a supposed ‘classical’ taxonomy. However, references to actual studies that would support such statements are rarely given; but are there any ? Very few works provide real, original, information on morphology. In fact, the taxonomy of trouts is difficult because of the lack of data usable in a taxonomic framework (and this includes molecular data), because of the use of outdated concepts and methods, because of the generalisation of studies of some populations/species to the whole genus, because of the confusing use of taxonomic terminology out of context, and maybe also because of a kind of 'fear' to handle more than a few species or names.
There has been little attempts to handle trout taxonomy in the same way as the taxonomy of any other fish or animal groups. Trout 'taxonomy' is a specialty of its own in which taxonomists do not seem to be welcome. Social factors play a great role, including bureaucratic inertia, bad will, tradition, politics, business, chauvinism, competition, careers. A sound approach to trout taxonomy requires real, usable data, freshly obtained by trained taxonomists (not a re-hash of old incompatible data). Then, they should be handled as any other data for any other group of fish, in using the appropriate terminology; at an appropriate geographic scale (drainage level); and generalisation must be avoided.
Examples will be taken from recent works on trouts of Turkey to discuss variability, diagnosability, terminology, geographic scale, nomenclature, etc.