A STUDY ON THE ELABORATION OF A COLORATION PROTOCOL ON THREE SMALL-SIZE FRESHWATER FISH SPECIES: CARASIUS GIBELIO (BLOCH, 1782) PSEUDORASBORA PARVA (TEMMINCK & SCHLEGEL, 1846) AND ALBURNUS ALBURNUS (LINNAEUS, 1758) (PISCES, CYPRINIDAE), USEFUL IN AGE-DETE
The aim of the current paper is to establish a protocol which can be used in determining the age of small-sized fresh water fish, based on direct observation of growth rings (annuli and circuli) within the scale structure. The method simplifies the currently existing procedures (extraction of a certain number of scales, scouring, polishing, observation) therefore facilitating the age determination process during field activities. The authors propose a method consisting of extraction, superficial mechanical cleaning and coloration, which considerably shortens the processing time but with good results in microscopy observations. Another aspect is that small-sized fish have less rigid scales and the risk of mechanical deterioration during polishing procedures in more likely, making them improper for observations. At the same time simple observations by transparency, after polishing, may be irrelevant.
